Electrical safety. Basic concepts Electrical safety is a system of organizational and technical measures and means to protect people from. Name of chairmancorporate technical - safety, health and environment1 briefing for assigning i group

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 current in the legs, convulsions occur, 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 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-metal 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.

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 3 Electrical safety group I for non-electrical personnel is assigned after an annual test of knowledge of safe methods of working with electrical equipment (within the scope of work performed) by a person with an electrical safety group of at least III. INSTRUCTIONS FOR ASSIGNING 1 GROUP ON ELECTRICAL SAFETY TO NON-ELECTRICAL PERSONNEL

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 4 Approximately 50% of accidents hit electric shock, occurs during work In terms of the frequency of deaths, electrical injuries are several times higher than other types of injuries. Statistics

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 5 Feature 1: Electricity is invisible and odorless. Feature 2: electric current acts not only at the points of contact, but also disrupts the activity of organs (cardiovascular system, respiratory system). 3 feature: damage through an electric arc or the possibility of electrical injury when moving on the ground (floor) near a damaged electrical installation. Dangerous features of electric current

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 6 Minimal concepts and terms electrical energy and converting it into another type of energy Electrotechnical personnel Maintenance, repair, management of the operating mode of electrical installations Non-electrotechnical personnel Production personnel that do not fall under the definition of "electrotechnical" personnel

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 7 AC current limit 0.3 mA. At 0.6-1.6 mA - slight hand trembling. At 8-10 mA, the muscles of the hand (in which the conductor is clamped) contract, the person is not able to free himself from the action of the current. At mA or more - fibrillation (flutter) of the heart. An electrical current of 100 mA or more is lethal. The general reaction of the body depends on its value Current strength A V Ohm

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 8 The human body conducts electricity The resistance of the human body consists of three components: 1- skin resistance (at the contact points), 2- internal organs, 3- blood vessels. human body resistance

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 9 The main drag value is leather. When the skin is moistened and damaged at the points of contact, its resistance drops sharply. The resistance of the skin is greatly reduced with increasing density and area of ​​contact. At voltage B, an electrical breakthrough of the upper layer of the skin occurs. human body resistance

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 10 depends on the duration of the electric shock. For example, electric eels and rays can cause unconsciousness. But having a voltage of 600 V, with a current strength of 1 A, they are not capable of causing a fatal shock, since the duration of the discharge is too short - on the order of several tens of microseconds.

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 11 Prolonged exposure to electric current reduces skin resistance. A person can withstand an alternating current value of 100 mA if the duration of current exposure does not exceed 0.5 seconds. Residual current devices (RCDs) have been developed that provide shutdown of the electrical installation in no more than 0.20 seconds. The severity of the lesion

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 12 People who are sick or weak, or who are depressed, nervous or intoxicated are more sensitive to electric current. The severity of the lesion

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 15 In a right arm-leg injury, 6.7% of the total electrical current passes through the human heart. With the leg-to-leg path, only 0.4% of the total current passes through the human heart. 0.4% 6.7% Electric current path through the human body

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 16 If a person stands on the ground in an area where electric current flows, voltage will be generated along the stride length and electric current will flow through his body. Above 1000V, the step voltage zone is 8-10m. When the voltage is below 1000V, the step voltage zone is 5-8m.

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 18 turn on the electrical equipment by inserting a working plug into a working socket; do not transfer electrical equipment to persons who do not have the right to work with it; Electrical safety measures at work and at home

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 19 if during operation a malfunction of electrical equipment is detected or the person working with it feels even a slight current, work must be stopped and the faulty equipment must be handed over for inspection or repair; always turn off electrical equipment during breaks and at the end of work Electrical safety measures at work and at home

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 21 While working on the computer, plug the PC into the mains, observing the following sequence: -voltage stabilizer (if used), -uninterruptible power supply, -peripheral devices (printer, monitor, scanner and etc.), -system unit; Electrical safety measures at work and at home

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 22 touch panels with equipment connectors, cable connectors; reduce the ingress of moisture on the surface of the equipment; independently open and repair equipment; do not wipe dust on the switched on equipment During operation, you must not: Electrical safety measures at work and at home

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 23 Completely turn off the electricity in the room, unplug the power cord. If this is not possible: - to protect yourself - stand on insulating material (rubber mat, dry board, dry books or a pack of dry paper); – pull the victim out with a non-conductive electric current object (dry wooden mop, board, using a loop made of rope, towel, scarf, etc.) First aid in case of electric shock

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 24 You can pull the casualty by the clothes (if they are dry and loose from the body), while avoiding touching the surrounding metal objects and exposed parts of the casualty's body. You need to act with one hand, the other should be in your pocket or behind your back! Next, you need to drag the victim to a safe place. First aid for electric shock

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 26 First aid should be provided within the first 2-3 minutes Heart failure may occur a few hours later Peripheral vascular disturbances may be detected a week after injury Even with a minor electric shock, the victim should seek medical attention see a doctor First aid for electric shock

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 27 Statistics show that up to 92% of the victims can be saved by applying methods of resuscitation in the first 2 minutes after the onset of clinical death. First aid for electric shock

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 28 Before the ambulance arrives: – bring the victim to his senses if he is unconscious by pressing on the pain point; - if breathing stops, immediately start artificial respiration and chest compressions until the doctor arrives. First aid for electric shock

Name of chairman Driving Excellence in SAFETY, HEALTH AND ENVIRONMENT 29 The victim must be given complete rest, not allowed to move, as the condition may worsen due to burns of internal organs and tissues. The consequences of internal burns may appear during the first day or the next week. First aid for electric shock

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 only

possible 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 consequences
electric 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 whole
a 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 current
There are three criteria per person:
threshold
tangible
current
(least
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

Much
dangerous
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 only
when an electrical circuit is closed through the human body. This
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 circuit
a - 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 dielectric
material - 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
heightened 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;
facilities personal protection.

GOST 12.1.030 are subject to protective grounding:

1. Metal non-current-carrying parts of equipment, to
which 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
above;
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 has
insulation 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 funds for repair work under voltage above 1000
IN.

Additional insulating protective equipment

Additional insulating protective equipment is not
capable 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 equipment
1, 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 for
temporary 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 for
personal 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 must
rather 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 from
current-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 fast
disconnection 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 two
points 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 not
exceeds 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
from
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
of people
electric
current
these
territory
are considered as especially dangerous premises.

Characteristics of industrial premises for electrical safety

Damp rooms are rooms in which
relative 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
from
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 deformation
solids, 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 static
pose 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

Normalized
parameter
field strength E, (V/m)
ESP
is an
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 of
dangerous
spark
discharges
static
electricity
from
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 - lightning
can cause explosions, fires and injury
of 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 ground
objects 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

1
4
2
3

Lightning rods

Single rod lightning rod - one vertical
lightning 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 of
the 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.

electrical safety

Do not forget: electricity not only makes our life easier, but in a certain situation it threatens it.

Performed:

Aristova V.A.,

teacher of OSAPOU "BSK"

There is no safe current!

A person, touching the current-carrying parts of electrical installations and uninsulated wires under voltage, is included in the electrical circuit. Under the influence of voltage, an electric current flows through his body, which disrupts the normal functioning of the body, which causes convulsions, burns, breathing stops and the heart stops. The person dies or becomes disabled.

Basic electrical safety rules

Electricity is an invisible danger

It is invisible, imperceptible, tasteless and odorless, but it IS

The voltage at 12V (volts) is already dangerous for humans

Annually

from electric shock

more than died in the world

40 thousand people

Electricity at home

• Independently repair electrical wiring and electrical appliances
• Use faulty household appliances
• If, upon touching the device, you feel a tingling or tingling sensation, then the device is faulty and is energized.

NECESSARY:

• Switch off the damaged device immediately
• Warn others of the danger

Basic Rules electrical safety

If you find sagging wires or broken power lines

IT IS FORBIDDEN:

Touch broken wires and approach closer than 8 - 10 m. Step voltage is deadly!

Play close to broken lines

NECESSARY immediately inform adults about the place of the break

DO NOT PLAY under power lines and DO NOT THROW on wires, wires and other objects

DO NOT OPEN doors of switchboards, power cabinets, doors of transformer substations

Electrical Safety Rules!

DO NOT INCLUDE immediately all electrical appliances into the socket. Network overload can cause a short circuit

DO NOT RUN with friends on the roofs - there may be live wires

electric shock - damage to the body by electric current, in which the excitation of living tissues is accompanied by convulsive muscle contraction

• electrical injury I degree - convulsive muscle contraction without loss of consciousness;

• electrical injury II degree - convulsive muscle contraction with loss of consciousness;

• electrical injury III degree - loss of consciousness and dysfunction of cardiac activity or respiration (it is possible both);

• electrical injury IV degree - clinical death.

Safe for humans considered: alternating current up to 10 mA direct current - up to 50 mA

The severity of electrical damage depends on many factors: the resistance of the body, the magnitude, duration of action, the type and frequency of the current, its path in the body, environmental conditions.

Electrical burn various degrees - a consequence of short circuits in electrical installations and the stay of the body (usually hands) in the sphere of light (ultraviolet) and thermal (infrared) influence of an electric arc

Exemption from the action of electric current

The provider of assistance must first of all release the victim from the action of the current on him: turn off the power if possible.

• wherein simultaneously persons not participating in the provision of assistance to the victim should immediately :
• call a doctor medical unit or ambulance;
• delete from the point of care strangers ;
• create maximum illumination as well as fresh air supply

Danger electric shock is a violation of the activity of the respiratory organs and the cardiovascular system .

First of all necessary , do the following:

- lay the victim on his back on a hard surface

• verify, does he have breathing and pulse ;
• examine the pupil(narrow or wide). Wide badge points to a sharp deterioration in the blood supply to the brain.

After that, you need to start providing first aid:

If the victim is conscious, but before that he was fainting or under current for a long time, he must be carefully placed in a comfortable position, covered warmly, and ensure complete rest until the doctor arrives. And, without losing vigilance, continuously monitor breathing and pulse

If the victim is unconscious, but steady breathing and pulse have been preserved, he should be comfortably laid down, unbuttoned the collar, belt and clothes, provided with fresh air and complete rest, give the victim to smell ammonia and sprinkle it with water

If the victim breathing badly- rarely, convulsively, as if sobbing - it is necessary to do artificial respiration and cardiac massage .

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 transfer 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. Defeat 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 various groups muscles can lead to convulsions, respiratory arrest and cardiac arrest. 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 during emergency operation of electrical installations according to GOST: Current type and frequencyNorm. 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 earth 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 ground 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