Electrical safety Group 1 presentation on the new rules. Presentation on the topic "Electrical safety posters and signs used in electrical installations". Signs and posters
Simple rules that everyone should know.
1. The most important rule is to remember that there is no safe electricity! Of course, you can not be afraid of toys that run on batteries, in which the voltage is only 12 volts. But in everyday life, electricity with a voltage of 220 - 380 volts has become most widespread.
2. If you are not a specialist, you cannot independently repair electrical wiring and household appliances connected to the network, open the back covers of TVs and radios, set bells, switches and sockets. This must be done by a qualified electrician!
3. Do not use switches, sockets, plugs, bell buttons with broken covers, as well as household appliances with damaged, charred or twisted cords. It is very dangerous! Never pull the plug out of the socket by the cord or use plugs that do not fit into sockets.
4. The rule is as old as the world, but for some reason many neglect it: do not handle electrical wires with wet hands and do not use electrical appliances in the bathroom. Remember also that in the event of a fire, under no circumstances should you extinguish live appliances with water.
5. If you feel “tingling” or “shaking” when touching the body of an electrical appliance, pipes and taps of water supply, gas, heating, bath and other metal objects, this means that this object is under voltage as a result of some kind of damage electrical network. This is a serious danger signal!
6. A broken power line wire lying on the ground or concrete floor is a great danger. Walking around the area around the wire, a person may be under the "step voltage". Under the action of the current, convulsions occur in the legs, the person falls, and the current circuit closes along his body through the respiratory muscles and heart. Therefore, when you see a broken wire lying on the ground, in no case approach it at a distance closer than 8 meters (20 steps). If you still got into the zone of "step stress" you can not tear off the soles from the ground. You should move away from the wire with a “goose step” - the heel of the walking leg, without leaving the ground, is attached to the toe of the other leg.
7. The wires of overhead lines located in the crown of trees or shrubs pose a great danger. Do not touch or shake such trees, especially in wet weather! Many people believe that a tree - a dielectric - does not conduct current, but, roughly speaking, there are drops of water on the foliage of a tree, and water is a conductor of electricity. In addition, it is very dangerous to fish under power lines. Carbon fiber rods also conduct current, which can occur if the wires are touched. Do not play near power lines, do not light fires under them, do not stack firewood, straw and other flammable objects nearby!
8. The first thing to do in case of electric shock to a person is to eliminate its source, while ensuring your own safety. You need to turn off the electricity. If a person touches a bare wire, you need to move the wire away from the victim with a non-metallic stick, or cut the wire with an ax with a wooden handle, or wrap your hand with a dry cloth and drag the victim by the clothes.
9. If breathing and pulse are absent, give artificial respiration. If there is breathing, but there is no consciousness, you need to turn the victim on his side and call an ambulance. On the palms of a person who touched the wire, electrical burns remain - there are always two of them - places of entry and exit. Cool the burn area under cold water for at least 15 minutes, then apply a clean cloth bandage. It is not necessary to treat burns with an antiseptic!
The emergency number is 112.
Description of the presentation on individual slides:
1 slide
Description of the slide:
Class hour on the prevention of children's electrical injuries "Electrical safety at home and on the street"
2 slide
Description of the slide:
The objectives of the class hour: 1. to generalize and expand the knowledge of schoolchildren about electricity; 2. form ideas about how electricity affects the human body; 3. fix the rules for the safe handling of electrical appliances.
3 slide
Description of the slide:
Guys! You know very well what an important role electricity plays in our lives. It gives us light, heat, sets in motion various mechanisms that facilitate human work. Electricity has taken such a strong place in our lives that now it is simply impossible to do without it. She is our indispensable assistant. But, providing great help to people, electricity is fraught with mortal danger for those who do not know or neglect the rules of electrical safety, handling household appliances, violates the rules of behavior near power facilities. Any electrical installation is a danger to human life. ATTENTION! ELECTRICITY DANGEROUS!
4 slide
Description of the slide:
Electrical installations are equipment used by power engineers, and everything that surrounds us in everyday life is electrical appliances. A person, touching the current-carrying parts of electrical installations and uninsulated wires under voltage, becomes involved in the electrical circuit. Under the influence of voltage, an electric current flows through his body, which disrupts the normal functioning of the body, due to which convulsions occur, breathing stops and the heart stops working. When overheating of certain parts of the body, severe burns occur. The person dies or becomes disabled. Electrical installations are equipment used by power engineers, and everything that surrounds us in everyday life is electrical appliances. ATTENTION! ELECTRICITY DANGEROUS!
5 slide
Description of the slide:
The greater the amount of current flowing through the body, the more dangerous it is! The magnitude of the current is greater, the higher the voltage under which the person turned out to be. The safe voltage is 12 volts. The most widespread in industry, agriculture and everyday life are electrical networks with a voltage of 220 - 380 volts (220 volts for lighting and household appliances, 380 volts for three-phase electric motors). This voltage is very dangerous for humans. The greatest number of deaths occurs with people who are under voltage of 220 - 380 volts. ATTENTION! ELECTRICITY DANGEROUS!
6 slide
Description of the slide:
7 slide
Description of the slide:
The effect of electric current on the human body The danger of electric current lies in the fact that a person does not have special sense organs to detect electric current at a distance. Electric current is odorless, colorless and operates silently. It is impossible to feel without special devices whether a given part of the electrical installation is energized or not. This leads to the fact that people often do not realize the real danger and do not take the necessary protective measures. ATTENTION! ELECTRICITY DANGEROUS!
8 slide
Description of the slide:
Electric current, passing through the human body, has a biological, electrolytic, mechanical and thermal effect. The thermal effect is manifested in the form of burns of the skin of the body, overheating of various organs, as well as ruptures of blood vessels and nerve fibers resulting from overheating. The electrolytic action is expressed in the decomposition of an organic liquid, including blood, which is accompanied by significant disturbances in their physicochemical composition. The biological effect is manifested in irritation and excitation of living tissues of the body, as well as in violation of internal bioelectrical processes, which leads to involuntary convulsive muscle contractions, disorders of the nervous system, respiratory and circulatory organs. In this case, fainting, loss of consciousness, speech disorder, convulsions, respiratory failure (up to a stop) can be observed. The mechanical action is manifested in the occurrence of pressure in the blood vessels and tissues of the body when blood and other fluids are heated, as well as the displacement and mechanical stress of tissues as a result of involuntary muscle contraction and the impact of electrodynamic forces. ATTENTION! ELECTRICITY DANGEROUS!
9 slide
Description of the slide:
Of great importance in the outcome of the defeat is the path traversed by the current in the human body. The defeat will be more severe if the heart, chest, brain and spinal cord are in the path of the current. The most dangerous paths for the passage of current through a person are: arm-legs, arm-arm. The immediate causes of death of a person struck by an electric current are the cessation of the heart, respiratory arrest due to paralysis of the chest muscles and electric shock. The most unfavorable outcome of an electric shock to a person will be in cases where the touch occurred with wet hands in a damp or hot room. ATTENTION! ELECTRICITY DANGEROUS!
10 slide
Description of the slide:
11 slide
Description of the slide:
Rules for handling electrical appliances at home ATTENTION! ELECTRICITY DANGEROUS!
12 slide
Description of the slide:
Rules of conduct on the street near power facilities Power facilities are overhead and cable power lines, substations, transformer substations, distribution points. Overhead power lines with a voltage of 35, 110 kilovolts and above are responsible for the power supply of cities and towns. Overhead and cable power lines with a voltage of 6, 10 kilovolts are responsible for power supply within cities and towns, as well as rural settlements. Power lines with a voltage of 380 volts provide electricity to apartment buildings, and 220 volts - individual apartments. Substations are divided into high-voltage substations - 35 kilovolts and above and transformer substations with a voltage of 6, 10 kilovolts. Substations are designed to reduce the voltage in the AC network and to distribute electricity. Transformer substations are located in every settlement and, due to their ubiquity, pose a particular danger to the population! All power facilities carry a real danger to life! ATTENTION! ELECTRICITY DANGEROUS!
13 slide
Description of the slide:
Warning signs about the danger of electric shock To prevent accidental entry into electrical installations, and thereby prevent electric shock to people, there are special warning signs and posters. They are hung out or applied to the supports of overhead power lines of any voltage, the doors of various electrical panels in which electrical equipment is located, on fences and fences that enclose electrical installations. The presence of such signs implies a ban on the entry of the population into electrical installations or climbing to the support of power lines. Signs warn a person about the danger of electric shock. It is unacceptable to neglect them, and even more so to remove and pluck them. ATTENTION! ELECTRICITY DANGEROUS!
14 slide
Description of the slide:
Warning signs about danger of electric shock Prohibiting posters Warning signs and posters Mandatory posters Index poster ATTENTION! ELECTRICITY DANGEROUS!
15 slide
Description of the slide:
A large number of accidents involving electric shock occur as a result of touching wires, including slack ones, and approaching or touching broken wires lying on the ground. Even after a break, the wire may be energized. At the same time, the electric current begins to "drain" into the ground, and the area of \u200b\u200bthe ground around the wire is under an electric potential, and the farther from the point of contact of the wire with the ground, the lower the potential. ATTENTION! ELECTRICITY DANGEROUS!
16 slide
electrical safety–
system
organizational
and
technical measures and means to ensure the protection of people
from the harmful and dangerous effects of electric current,
electric arc, electromagnetic field and static discharges
electricity.
Characteristics of the dependence of human electric shock
Electric shock to a person is possible onlypossible with:
touching open live parts of the equipment and
wires;
touching the housings of electrical installations that accidentally turned out to be
under voltage (insulation damage);
step voltage;
release of a person under tension;
the action of an electric arc;
exposure to atmospheric electricity during thunderstorms
discharges.
Electric current passing through the human body
has a profound effect on it:
thermal;
electrolytic;
biological;
mechanical.
The effect of electric current on the human body
The thermal effect of the current is manifested in body burns,heating and damage to blood vessels, nerves, blood, brain
and other organs, which causes their serious functional
disorders.
The electrolytic effect of the current is manifested in
decomposition of blood and other body fluids, causing
significant violations of their physico-chemical composition, as well as
tissue in general.
The biological effect of the current is expressed mainly in
disruption of biological processes occurring in living
body, which is accompanied by destruction and excitation
tissue and muscle contraction.
The mechanical effect of the current is manifested in skin ruptures,
blood vessels, nervous tissue, as well as dislocations of the joints and
even bone fractures due to sudden involuntary
convulsive contractions of muscles under the influence of a current passing through
through the human body.
Types of electric shock
electrical injuries - electrical burns,electrical signs,
skin electroplating,
electrophthalmia and mechanical damage;
electric shocks refer to the type of lesions,
that occur when exposed to small currents
(of the order of several hundred milliamps) and voltages up to
1000 V
electrical injury
An electrical burn can be caused by an electric arc.(arc burn) or the passage of current through the human body in
as a result of its contact with the current-carrying part (current burn).
Electrical signs (current signs or electrical labels)
are dead spots on human skin,
exposed to current.
The electroplating of the skin is due to the penetration into
its upper layers of the smallest particles of metal melted under
the action of an electric arc.
Electrophthalmia - inflammation of the outer membranes of the eyes,
resulting from exposure to a stream of ultraviolet
rays.
Mechanical damage occurs as a result of sudden
involuntary convulsive muscle contractions under the influence of
current.
4 degrees of electric shock
Depending on the consequenceselectric shocks are divided into four degrees:
I - convulsive muscle contraction without loss of consciousness;
II - convulsive muscle contraction with loss of consciousness, but
with preserved breathing and heart function;
III - loss of consciousness and violation of the heart
activity or breathing (or both);
IV - the state of clinical death (lack of breathing
and circulation).
Factors affecting the outcome of human electric shock
The severity of electric shock depends on the wholea number of factors:
current values;
kind and frequency of electric current;
paths for the passage of current through a person;
the duration of the passage of current through a person;
voltage;
electrical resistance of the human body and its individual
properties;
area and density of contact with live parts;
environmental conditions.
The main factor that determines one or another
the degree of damage to a person is the strength of the current.
Degree of electric shock
To characterize the impact of electric currentThere are three criteria per person:
threshold
tangible
current
(the fewest
meaning
strength
electric current that, when passing through the body, causes
human tangible irritation);
threshold non-release current (the smallest value of the force
electrical current that causes irresistible convulsions
contraction of the muscles of the hand in which the conductor is clamped);
threshold fibrillation current (the smallest value of the current strength,
causing fibrillation when passing through the human body
hearts - chaotic and multi-temporal contractions of fibers
heart muscle, completely disrupting the work of the heart as
pump).
Pathways for the passage of electric current into the human body
Muchdangerous
considered
way
passing through vital organs (heart,
lungs, brain)
"head - hand";
"head - legs";
"hand - hand";
"hands-legs".
Characteristic current paths in the human body
Causes of electric shock to a person
Electric shock to a person is possible onlywhen an electrical circuit is closed through the human body. it
may be with:
two-phase inclusion in the circuit;
single-phase inclusion in the circuit - wires, terminals, tires, etc.;
contact of a person with non-current-carrying parts of the equipment (housing
machine,
device),
constructive
elements
building,
energized as a result of insulation failure
wiring and live parts.
Two-phase inclusion in the circuit a - isolated neutral; b - grounded neutral; A, B, C - phase wires; REM - zero protective and zero
Two-phase inclusion in the circuita - isolated neutral;
b - grounded neutral;
A, B, C - phase wires;
REM - zero protective and zero working conductors,
combined into one conductor
Single-phase contact in a network with a grounded neutral a - normal operation; b - emergency operation (damaged second phase); R0
- grounding resistance of the neutral wire;Rk is the resistance of the wire to ground
Single-phase contact in a network with isolated neutral a - normal operation; b - emergency operation (damaged second phase)
Measures of protection against the action of electric current
insulation of current-carrying parts (application of a dielectricmaterial - plastics, rubber, varnishes, paints, enamels, etc.);
double insulation - in case of damage to the working;
overhead lines, cables in the ground;
fencing of electrical installations;
blocking
devices,
automatically
shutting down
voltage of electrical installations when their protective covers are removed
and fences;
low voltage (not more than 42 V) for lighting in conditions
increased danger;
isolation of the workplace (floor, flooring);
grounding or grounding of electrical installations, which
may become energized if the insulation is damaged;
equalization of electrical potentials;
automatic shutdown of electrical installations;
warning signaling (sound, light) when
the appearance of voltage on the installation case;
inscriptions, posters, signs;
personal protective equipment.
GOST 12.1.030 are subject to protective grounding:
1. Metal non-current-carrying parts of equipment, towhich can be touched by people;
2. All electrical installations in rooms with increased
danger and especially dangerous, as well as external
electrical installations at a voltage of 42 V AC
current and 110 V DC;
3. All AC electrical installations in the premises
without increased danger 380 V and alternating 440 V and
higher;
4. all electrical installations in hazardous areas.
Types of protective equipment against electric shock
Electrical protective equipment is divided into:insulating (basic and additional);
enclosing;
safety
Basic insulating protective equipment
Basic insulating protective equipment hasinsulation capable of withstanding operating voltage for a long time
electrical installations, and therefore they are allowed to touch current-carrying
live parts. These include:
in electrical installations up to 1000 V - dielectric gloves,
insulating rods, insulating and electrical clamps,
fitting and assembly tool with insulating handles, and
also voltage indicators;
in electrical installations above 1000 V - insulating rods,
insulating and electrical clamps, voltage indicators,
as well as means for repair work under voltage above 1000
AT.
Additional insulating protective equipment
Additional insulating protective equipment is notcapable of withstanding the operating voltage of the electrical installation. They are
enhance the protective effect of the main insulating agents,
with which they are to be applied. Additional
funds alone cannot provide security
service personnel. These include:
in electrical installations up to 1000 V - dielectric galoshes and carpets, and
also insulating supports;
in electrical installations above 1000 V - dielectric gloves, boots
and carpets, as well as insulating pads.
Insulating protective equipment 1, 3 - insulating rods; 2 - insulating pliers; 4 - dielectric gloves; 5 - dielectric boots; 6 - d
Insulating protective equipment1, 3 - insulating rods; 2 - insulating pliers; 4 - dielectric gloves;
5 - dielectric boots; 6 - dielectric galoshes; 7 - rubber mats
and tracks; 8 - insulating stand; 9 - assembly tools with insulated
handles; 10 - current clamps; 11, 12, 13 - voltage indicators
Enclosing protective equipment
Enclosing protective equipment is intended fortemporary fencing of live parts and warnings
erroneous operations with switching devices.
These include: temporary portable fences - shields and
cage fences, insulating pads, temporary portable
grounding and warning posters.
Safety protective equipment
Safety protective equipment is intended forpersonal protection of workers from light, heat and other
impacts.
These include: safety goggles; special gloves,
protective helmets; gas masks; safety fitter's belts;
safety
ropes;
fitter's
claws,
individual
shielding kits and portable shielding devices and
others
First aid for accidents caused by injury
electric current, consists of two stages:
release of the victim from the action of the current;
providing first aid to the victim.
First aid rules for victims of electric shock
In the event of an electric shock, you mustrather release the victim from the action of the current, since
The severity of an electrical injury depends on the duration of its action.
Signs by which you can quickly determine the status
victim:
consciousness: clear, absent, impaired (the victim is inhibited),
the person is excited;
color of the skin and visible mucous membranes (lips, eyes): pink,
bluish, pale;
breathing: normal, absent, disturbed (wrong,
superficial, wheezing);
pulse on the carotid arteries: well defined (correct rhythm
or incorrect), poorly defined, absent;
pupils: narrow, wide.
First aid rules for victims of electric shock (at voltage up to 1000 V)
At voltages up to 1000 V, to separate the victim fromcurrent-carrying parts, you can use any non-conductive
current objects: wrap your hand with a scarf, pull it by the clothes,
stand on a bundle of dry cloth, a dry board.
Even with a bare hand, you can pull dry clothes,
lagging behind the body (behind the collar, strap, half of the jacket).
Do not pull on pants or shoes that could be
wet or have metal parts in contact with the body.
Release of the victim from the action of current in installations up to 1000 V by pulling dry clothes
Rules for providing first aid to victims of electric shock (at a voltage of more than 1000 V)
If in an installation with a voltage of more than 1000 V, a fastdisconnection is not possible, then use any
improvised means such as a stick, board or dry clothes
it is forbidden.
In this case, it is necessary to wear dielectric gloves and
boots and pull the victim away from the parts of the installation located
under voltage, using insulating protective equipment,
designed for this voltage (rods, tongs for
fuses or mats), or call an automatic
shutdown of the installation by arranging a short circuit in it to
a safe distance from the victim.
Release of the victim from the action of the current in installations above 1000 V by discarding the wire with an insulating rod
Step voltage
Step voltage is the potential difference between twopoints on the earth's surface in the zone of current spreading, which
are at a walking distance (0.8 m).
The reason for the appearance of step voltage is
the formation of electrical potentials on the surface of the earth in
within the current spreading field (short circuit in the ground that occurs when
fall of an electric wire to the ground, short circuit of current-carrying
parts to a grounded frame, between points of earth or other
a surface on which a person stands with both feet)
Step voltage
The step voltage depends on:current strength;
potential distribution over the earth's surface;
stride length;
position (distance) of a person relative to grounding;
direction in relation to the closure.
Step voltage and man
Step voltage is considered safe if it is notexceeds 40 V.
The closer the person is to the point of contact
wires with the ground, the more step voltage it
will turn out.
At a distance of more than 20 m from the place of the short circuit of the current-carrying
parts to ground potential is reduced quite significantly.
If a person is under the action of step voltage,
then it is necessary to leave the zone of spreading of electric current
small steps (for the length of the foot), sliding the sole of the shoe on the ground,
without lifting your legs.
In accordance with the Rules for the installation of electrical installations
(PUE) regarding the danger of electric shock to people
current differ:
1. Premises without increased danger, in which
2.1 dampness
or conductive
dust; increased or
missing
conditions that create
danger. floors (metal, earth,
2.2 special
conductive
2. The premises are brick
With
danger
reinforced concrete,
and elevated
etc.);
characterized
2.3 high
temperature; the presence of one of
following simultaneous
conditions,
creating
increased
2.4 possibilities
touch
person to
danger:
metal structures connected to the ground
buildings, technological devices, mechanisms, etc., with
one
hand,
and
to
metallic
corps
electrical equipment on the other.
Classification of industrial premises according to the danger of electric shock
3.Particularly dangerous premises, characterized by
the presence of one of the following conditions that create
special danger:
3.1 extreme dampness;
3.2 chemically active or organic media;
3.3 simultaneously two or more conditions of increased
danger
4.
Territories
accommodation
outdoor
electrical installations. With regard to the risk of injury
people
electric
current
these
territory
are considered as especially dangerous premises.
Characteristics of industrial premises for electrical safety
Damp rooms are rooms in whichrelative air humidity exceeds 75% for a long time.
Dusty rooms are rooms where
according to the conditions of production, process dust is released into
in such an amount that it can settle on the wires, penetrate
inside machines, devices, etc.
Hot rooms are rooms in which
under the influence of various thermal radiation temperature
exceeds constantly or periodically more than 1 day. + 35 °С
(for example,
premises
With
dryers,
drying
and
kilns, boiler rooms, etc.).
Particularly damp rooms are rooms in which
where the relative humidity is close to 100% (ceiling,
walls, floor and objects in the room are covered
moisture).
Premises with chemically active or organic
The environment refers to the premises in which constantly or during
for a long time contain aggressive vapours, gases,
liquids, deposits or molds form that destroy
insulation and current-carrying parts of electrical equipment.
Static electricity
Charges of static electricity are formed during deformationsolids, splashing liquids, moving (friction)
solid, friable and liquid bodies.
Under static electricity accepted
understand the electrical discharges that are in
a state of relative rest, distributed over
surface or in the bulk of the dielectric or on
current conductor surface.
moving
charges
static
electricity
in
space usually occurs together with electrified
bodies.
The effect of static electricity on the human body
For human discharges of staticpose a direct threat.
electricity
not
Human exposure to static electricity can
manifest itself in the form of a weak continuous current flowing or in
the form of a short-term discharge passing through his body.
Such a discharge causes a reflex movement in a person.
On the human body, static electricity can
accumulate:
when wearing shoes with non-conductive soles,
when wearing clothes and underwear made of wool, silk and artificial
fibers;
when performing a number of manual operations with substances and dielectrics.
Rationing of the electrostatic field
Normalizedparameter
field strength E, (V/m)
ESP
is
Maximum permissible tension levels
electrostatic field (EPD) are installed in
depending on the length of stay of staff
workplaces and should not exceed:
when exposed to up to 1 hour - 60 kV / m;
when exposed to more than 1 to 9 hours, the value of the EPD
is determined by the formula:
EPD 60 T,
where T is time, h.
Measures to protect against static electricity
To prevent the possibility ofdangerous
spark
discharges
static
electricity
With
surfaces
equipment,
pipelines, as well as from the human body, it is necessary
ensure the discharge of charges in the following ways:
discharge of charges by grounding the equipment and
communications;
ensuring constant electrical contact with
grounding the human body;
removal of charges by reducing the specific volumetric
electrical resistance;
neutralization
charges
through
use
radioisotope,
induction
and
others
neutralizers.
atmospheric electricity
Discharges of atmospheric electricity - lightningcan cause explosions, fires and injury
people.
Lightning
–
spark
discharge
static
electricity stored in thunderclouds.
The energy of the spark discharge of lightning and the resulting
currents pose a danger to humans, buildings
and structures. A direct lightning strike causes the following effects on
an object:
– electrical, associated with the defeat of people
electric current and the appearance of overvoltages on
damaged elements.
- thermal, associated with a sharp release of heat
- mechanical, due to the shock wave,
propagating from the lightning channel, and
electrodynamic forces acting on
conductors with lightning currents. Secondary manifestations
electrostatic induction
Electromagnetic induction
The drift of high potentials
Protection against atmospheric electricity
Lightning protection complex of protective devices,for the safety of people,
safety of buildings and structures, equipment and
materials from possible explosions, fires and
destruction
Lightning rods
Lightning protection against direct lightning strikes to groundobjects are carried out in the form of special devices,
called lightning rods.
By design, lightning rods are divided into:
rod;
cable.
Lightning rod device 1 - lightning rod; 2 – current lead; 3 - grounding; 4 - mast
14
2
3
Lightning rods
Single rod lightning rod - one verticallightning rod installed on the protected structure or
near him.
Double rod lightning rod - two single
rod lightning rods, acting together and forming
common area of protection.
Multiple lightning rod - three or more
single rod lightning rods, jointly acting and
forming a common zone of protection.
A single wire lightning rod is a device formed by
horizontal cable, fixed on two supports, for each
of which a down conductor is laid, connected to
a separate grounding conductor at their base.
Categories of lightning protection
Depending on the explosion hazard of objects,average annual duration of thunderstorms, as well as from
expected number of lightning strikes per year
established
3
categories
devices
lightning protection. Categories of lightning protection
3 categories of lightning protection devices are installed and
2 types (A, B) of zones for protecting objects from direct impacts
lightning.
The third category organizes the protection of objects,
The second category is protected
attributable
according to PUE
to fire hazardous
class zones
P-I, P-II, s
To
first
categories
relate
objects
objects classified according to the classification according to the PUE to
P-IIa at the location
objects
in areas of average
explosive
zones
regardless
explosive
zones
classes
B-Ia,
B-Iplaces
and
thunderstorm activity
20 hours
a year or more. (thunderstorm zone
protection
location
object
from to duration
intensity
B-IIa in areas
with an average
thunderstorms
type A, B).
activities
(type
zones
protection
objects A).
10 hours a year or more.
In the third category, outdoor installations are protected
Type of protection zone A or B
and open warehouses Buildings and structures classified by device
lightning protection to the first and second categories, must
be protected from direct lightning strikes, and secondary
manifestations through ground and underground metal
communications.
Buildings and structures classified by device
lightning protection to the third category, must be
protected from direct lightning strikes and high
potentials through ground metal structures.
Lightning protection zones
The protection zone of a lightning rod is part ofthe space within which the building and structure
protected from direct lightning strikes with a certain
degree of reliability.
Type A protection zone has a degree of reliability
99.5% and above, and type B protection zone - 95% and above.
Causes of electric shock Touching live parts under voltage; Touching the disconnected parts of the equipment on which voltage may occur: – in the event of a residual charge; - in case of erroneous switching on of the electrical installation or uncoordinated actions of the maintenance personnel; – in the event of a lightning discharge into or near the electrical installation; - touching metal non-current-carrying parts or associated electrical equipment (housings, casings, fences) after the voltage has transferred to them from live parts (the occurrence of an emergency breakdown on the housing). Damage by step voltage or a person being in the field of electric current spreading, in the event of a ground fault. Damage through an electric arc at a voltage of an electrical installation above 1 kV, when approaching an unacceptably small distance. The action of atmospheric electricity during lightning discharges. Releasing a stressed person.
Causes of electrical injuries A person cannot remotely determine whether the installation is energized or not. The current that flows through the human body affects the body not only at the points of contact and along the current flow path, but also on such systems as the circulatory, respiratory and cardiovascular systems. The possibility of electrical injury occurs not only when touched, but also through the step voltage.
The effect of electric current on the human body Electric current, flowing through the human body, produces a thermal, electrolytic, biological, mechanical effect. Common electrical injuries include an electric shock, in which the process of excitation of various muscle groups can lead to convulsions, respiratory arrest and cardiac activity. Cardiac arrest is associated with fibrillation - a chaotic contraction of individual fibers of the heart muscle (fibrils). Local electrical injuries include burns, electric signs, skin plating, mechanical damage, electrophthalmia (eye inflammation as a result of exposure to ultraviolet rays of an electric arc).
The nature of the impact of currents on the human body: ~ 50 Hz constant 1. Non-releasing mA mA 2. Fibrillation 100 mA 300 mA 3. Perceptible current 0.6-1.5 mA 5-7 mA 4. The current is considered acceptable, at which a person can independently break free from the electrical circuit
Maximum permissible levels (MPL) of contact voltage and current strength in emergency mode of electrical installations according to GOST: Kind and frequency of currentNorm. val.PDU, at t, s 0.01 - 0.08 over 1 Variable f = 50 Hz UDIDUDID 650 V 36 V 6 mA
Classification of premises according to the danger of electric shock (PUE) Class I premises. Particularly dangerous premises. (100% humidity; the presence of a chemically active environment or more than 2 factors of class 2) Class II premises. Areas of increased risk of electric shock. (one of the following factors are present:- increased temperature air (t = + 35 C); - high humidity (> 75%); - the presence of conductive dust; - the presence of conductive floors; - the possibility of touching at the same time to email. installation and to grounding or to two el. settings at the same time. Premises III class. Less dangerous areas. There are no features characteristic of the two previous classes. 75%); - the presence of conductive dust; - the presence of conductive floors; - the possibility of touching at the same time to email. installation and to grounding or to two el. settings at the same time. Premises III class. Less dangerous areas. There are no signs characteristic of the two previous classes."> 
Grounding resistance according to PUE PUE: grounding resistance should not exceed: in U installations 1000 V with an effectively grounded neutral (with low ground fault currents I out of 1000 V with an isolated neutral - 250 / I out, but not more than 10 Ohm; in U installations > 1000 V with isolated neutral, if the grounding device is simultaneously used for electrical installations with voltage up to 1000 V, - 125 / Iz, but not more than 10 Ohm (or 4 Ohm, if required for installations up to 1000 V). 1000 V with effectively grounded neutral (with low earth fault currents Iz 1000 V with isolated neutral - 250/Iz, but not more than 10 Ohm; in installations U > 1000 V with isolated neutral, if the grounding device is simultaneously used for electrical installations with voltage up to 1000 V, - 125 / Iz, but not more than 10 ohms (or 4 ohms, if required for installations up to 1000 V)."> 
Grounding Grounding is designed to eliminate the risk of electric shock in case of a short circuit to the body of electrical installations operating under voltage up to 1000 V in three-phase four-wire networks with a solidly grounded neutral. Grounding is the intentional connection of metal non-current-carrying parts of equipment that may be energized with a zero protective conductor. Zeroing turns the breakdown to the case into a short circuit and contributes to the flow of high current through the network protection devices and to the quick disconnection of damaged equipment from the network.
Protective equipment The main insulating electrical protective equipment is able to withstand the operating voltage of the electrical installation for a long time. in electrical installations with voltage up to 1000 V - dielectric gloves, tools with insulating handles and voltage indicators up to 1000 V; electrical installations with voltages above 1000 V - insulating rods, insulating and electrical clamps, as well as voltage indicators above 1000 V. Additional insulating electrical protective equipment has insufficient electrical strength and cannot independently protect a person from electric shock. Their purpose is to enhance the protective effect of the main isolating means. in electrical installations with voltage up to 1000 V - dielectric galoshes, rugs and insulating stands; in electrical installations with voltages above 1000 V - dielectric gloves, boots, mats, insulating stands
Posters and safety signs Warning: Stop! Tension, Don't get in! Kill, Test! Life threatening; Prohibiting: Do not include! People are working, Do not turn on! Work on the line, Do not open! People work, Work under stress! Do not re-enable; Prescriptive: Work here, Bury here; Forefingers: Grounded
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Slides captions:
Fatal electric shocks account for 2.7% of the total number of deaths. The number of deaths from electric current per year in the world reaches 22-25 thousand people.
Statistics
on electrical injury
Most accidents occur in electrical installations up to 1000 V
This is due to the fact that installations with voltages up to 1000 V are widely used, and a large number of people, as a rule, who do not have an electrical specialty, come into contact with electrical equipment.
The most common cause of electrical injury is non-compliance with electrical safety rules and the appearance of voltage where it should not be under normal conditions (on equipment cases, on metal structures of structures, etc.), which is most often caused by insulation damage
Attention!
The inability of the human body to detect an electric current before it begins to act, often leads to the fact that workers often do not realize the real danger and do not take the necessary protective measures in a timely manner. The inability of the human body to detect an electric current before it begins to act, often leads to the fact that workers often do not realize the real danger and do not take the necessary protective measures in a timely manner. The danger of electric shock is aggravated by the fact that the victim cannot help himself.
In case of inept assistance, the one who provides assistance may also suffer.
Attention!
Electric current is odorless, colorless and silent
General requirements Group I on electrical safety applies to non-electrical personnel of the company's office when using electrical equipment or electrical receivers switched on for a voltage of 220 V. Assignment of group I is carried out by instructing, testing the acquired knowledge in the form of an oral survey, if necessary, checking the acquired skills in safe ways of working or providing first aid in case of electric shock. Training and assignment employee I electrical safety group is made when he is hired and is confirmed annually. The results of the check are recorded in a special journal of the established form.The briefing is carried out by an employee from among the electrical personnel who has the 3rd electrical safety group, appointed by order of the head of the organization.
Employees of non-electrotechnical personnel are required to know:
- Electrical hazard;
- Electrical safety requirements for the operation of office electrical receivers;
- Techniques for the release of an employee who has fallen under the influence of an electric current;
- The procedure for providing first aid to the victim from the action of electric current.
Work related to the connection (disconnection) of wires, prevention, repair of electrical equipment (office equipment, electrical appliances) must be performed by electrical personnel with the appropriate qualification group for electrical safety.
Persons belonging to non-electrotechnical personnel are PROHIBITED to carry out the specified work.
Attention!
Passing through the human body, an electric current can produce thermal, electrolytic, mechanical, biological effects. Causes of death from electric shock include cardiac arrest, respiratory arrest, and electrical shock. Passing through the human body, an electric current can produce thermal, electrolytic, mechanical, biological effects. Causes of death from electric shock include cardiac arrest, respiratory arrest, and electrical shock. An electric shock is the result of the biological action of current, consisting in the excitation of nerve tissues when an electric current passes through the body. There are four degrees of electric shocks depending on the outcome of the impact on the body:
- involuntary convulsive muscle contraction without loss of consciousness (light, without loss of consciousness);
- convulsive muscle contraction with loss of consciousness, but with preserved breathing and heart function;
- loss of consciousness and impaired heart activity or breathing (or both);
- state of clinical death. An electric shock may not lead to the death of a person, but cause such disorders in the body that will appear in a few hours or days (appearance of cardiac arrhythmia, angina pectoris, absent-mindedness, weakening of memory and attention).
Employees of non-electrotechnical personnel are required to know:
Electric shock Electric shock is a severe neuro-reflex reaction of the body in response to excessive irritation with an electric current, accompanied by profound disorders of blood circulation, respiration, and metabolism. In case of shock, immediately after exposure to current, the victim enters a short-term phase of excitation, when he reacts sharply to the pain that has arisen, his blood pressure rises. This is followed by a phase of inhibition and exhaustion of the nervous system, when blood pressure drops sharply, the pulse drops and quickens, breathing weakens, and depression occurs. The state of shock lasts from several tens of minutes to a day.
The nature and consequences of exposure to an electric current depends on:
- resistance of the human body;
- the magnitude of the voltage and current passing through the vital organs;
- duration of current exposure;
- paths for the passage of current through the human body;
- individual properties of a person: health status;
- psychophysiological state.
Factors that significantly increase the likelihood of a fatal electric shock include:
- everything that increases the rate of the heart: fatigue, excitement, fear, taking alcohol, drugs, certain drugs, smoking, illness;
- anything that reduces skin resistance: sweating, cuts.
Percentage of total current passing through the heart:
- path hand - hand - 3.3% of the total current;
- path left arm - legs - 3.7% of the total current;
- path right arm - legs - 6.7% of the total current;
- path leg - leg - 0.4% of the total current.
Electrical safety requirements for the operation of office electrical receivers
When operating office equipment, electrical appliances and other electrical equipment, it is necessary to follow the instructions and rules set out in the instructions (technical data sheets, manuals) for the operation of the manufacturer.
Use a damaged socket, switch, cartridge, plug, etc.;
- use a damaged socket, switch, cartridge, plug, etc.;
- use the bare ends of the power cord of the devices instead of plugs;
- wipe the appliances and electrical fittings connected to the mains with a damp cloth, touch them with wet hands;
- simultaneously touch the electrical appliance and heating pipes, plumbing, housings of neighboring appliances;
- hang connecting wires, cords, cables on nails, metal objects or nail them to the wall, lay them behind pipes, pinch them with doors, window frames, etc.;
- twist, tie wires, power cords into a knot;
- remove the plug from the socket by the cord;
- use the appliance for other purposes, as well as in conditions that do not meet the requirements of the operating instructions;
- step on the cords of electrical appliances and extension cords, put any objects on them;
- carry equipment connected to the mains;
- put dishes with liquid on electrical equipment (vases with flowers, glasses with water);
- open electrical panels and cabinets, engage in switching in switchboards;
- store flammable or combustible liquids in the workplace.
- connect unknown electrical appliances to the network: they may be faulty or not designed for the mains voltage.
- exclude automatic releases (“automatic devices”) and RCDs from the circuit. In the event of a blown fuse, as well as an automatic release, it should be replaced with a new one of the same rating (current).
Not allowed:
If the plug does not hold well in the socket or heats up due to poor contact, sparks, crackles, stop using the emergency device and call a specialist.
- If the plug does not hold well in the socket or heats up due to poor contact, sparks, crackles, stop using the emergency device and call a specialist.
- It is necessary to regularly check the places where the cords exit the plug, that is, where the insulation is most often frayed and the wires are shorted.
- The bare places of the cord or wire should be carefully covered with two or three layers of insulating tape, but in no case should they be wrapped with cloth or paper.
- Electric heaters should only be used factory-made.
- Turning on and off office equipment, heating and other portable electrical appliances in the socket should be carried out using the plug, taking it by the insulated part - the block.
- Pulling the plug from the socket by the cord is unacceptable to avoid breaking the cord or exposing and shorting the wires.
- Feeling the action of an electric current when touching metal structures, you should immediately take measures to prevent people from entering the dangerous place and report this to the manager.
Safety Rules When Using Office Electrical Appliances
In the event of (detection) of malfunctions: sparking of electrical wiring, short circuit, increased noise level during equipment operation, increased heat generation from equipment, screen flickering, other malfunctions, smell of burning and smoke, power outage, etc., you should stop working, de-energize a faulty electrical appliance or office equipment. Do not start work until the troubleshooting!
Attention!
Connect more than one electric heater to the same outlet. Overloading the network with faulty protection can lead to premature drying of the insulation and fire of the wires.
Filling of electric heaters, teapots, coffee pots and other containers should be done with the device turned off to avoid electric shock due to simultaneous connection with the ground (through a tap) and the body of the appliance.
Forbidden
In case of electric shock to a person, it is necessary to assess the situation and protect yourself so as not to get energized yourself, quickly and carefully release the victim from the effects of current by turning off the device, installing it with the nearest switch, and unplugging the plug from the outlet.
- In case of electric shock to a person, it is necessary to assess the situation and protect yourself so as not to get energized yourself, quickly and carefully release the victim from the effects of current by turning off the device, installing it with the nearest switch, and unplugging the plug from the outlet.
- Break the current circuit (in electrical installations up to 1000 V) by cutting the wire using tools with insulated handles (knife, wire cutters, etc.).
- If it is impossible to turn off the installation to release the victim from the effects of electric current, it is necessary to separate him from the current-carrying parts.
The human body conducts current in the same way as an electrical wire.
Attention!
If the victim squeezed one of the wires, it is possible to break the electrical circuit through the victim, separating him not from the wire, but from the grounded parts. To do this, slip a dry board, plywood under the victim or pull his legs off the ground with a dry rope. If the victim squeezed one of the wires, it is possible to break the electrical circuit through the victim, separating him not from the wire, but from the grounded parts. To do this, slip a dry board, plywood under the victim or pull his legs off the ground with a dry rope.
Techniques for the release of an employee who has fallen under the influence of electric current
You can’t touch the exposed parts of the victim’s body with your bare hands, you can only touch the dry parts of his clothes, but it’s better to wrap your hand with a dry cloth, take the victim by the clothes and pull him away from the current-carrying parts. If possible, use dielectric protective equipment (gloves, boots, mats) for this.
Attention!
After the release of the victim from the action of electric current, it is necessary to assess his condition. After the release of the victim from the action of electric current, it is necessary to assess his condition.
- Lay the victim on his back on a hard surface;
- Check if the victim is breathing (determined by the rise of the chest);
- Check if the victim has a pulse; The victim's lack of consciousness, breathing, pulse, and the presence of such signs as bluish color of the skin or dilated pupils may indicate that the victim is in a state of clinical death. In this case, it is necessary to immediately start resuscitation measures.
The procedure for providing pre-medical
assistance to the victim from the action of electric current
First of all, you must immediately call a doctor. Only a doctor can finally determine the state of health of the victim!
Attention!
The duration of clinical death is approximately 4–8 minutes. After this time, the death of brain cells occurs, leading to the irreversible cessation of biological processes in the body, the disintegration of protein structures - biological death.
Attention!
If the victim is conscious, but before that he was unconscious, he should be laid on dry objects, unfasten his clothes, create an influx of fresh air, warm the body in cold weather or provide coolness on a hot day, create complete rest, continuously monitoring the pulse and breathing before the paramedics arrive. If the victim is conscious, but before that he was unconscious, he should be laid on dry objects, unfasten his clothes, create an influx of fresh air, warm the body in cold weather or provide coolness on a hot day, create complete rest, continuously monitoring the pulse and breathing before the paramedics arrive. If the victim is unconscious, it is necessary to observe his breathing and, if it is disturbed, to ensure the implementation of resuscitation measures. In a pre-fainting state (complaints of dizziness, nausea, tightness in the chest, darkening in the eyes), the victim should be laid down with his head slightly lower than the body, since when fainting, blood is drained from the brain. It is necessary to unbutton the clothes on the victim, provide an influx of fresh air, give cold water to drink and give a sniff of ammonia. The same should be done if fainting has already occurred. If it is impossible to call a doctor to the scene, it is necessary to ensure the transportation of the victim to the nearest medical facility. It is possible to transport the victim only with satisfactory breathing and a steady pulse. If the condition of the victim does not allow him to be transported, it is necessary to continue to provide assistance.
The procedure for providing first aid to the victim from the action of electric current
