General engineer support
T1/7– protection against electric shock
and first aid in case electric shock
Seminar
Course Objectives:
Clarify to students the possibilities of
protection against electric shock, including the
principles of First Aid for electric shock.
Table of Contents:
1. Introduction
2. Protection against electric shock
3. Protection zones of electrical equipment
4. First aid for electric shock
5. Conclusion
1. Introduction
Development of accident rate shows us that electric shock tend to
suffer mainly undisciplined workers who do not respect or knowingly violate
safety regulations. Mostly young workers (most injuries were reported among
workers aged 20 to 30 years) do not comply with safety regulations. Another
group of injured workers makes up people between 50 and 60 years of age, who
count on routine work or even medical reasons.
In general terms, the most common causes electric shocks are:
Ignorance of safety rules;
Violation of safety regulations;
Ignorance of danger during working with electricity;
Underestimating of electric shock risk;
Carelessness;
Failures of electrical devices or unprofessional repairs of electrical
installations.
2. Protection against electric shock
Basic concepts and terminology
Electrical device - stationary or mobile device for production, distribution
and power consumption.
Electrical items - items which are connected electrically or plugged into
the working circuit.
Dangerous touch voltages - is such voltage that may person who
touched conductive parts under power cause death or injury.
Grounding
Grounding is often part of electrical equipment. It is important for safety
from injury and often for their own operation.
3. Protective zones of electrical
equipment
Protective zone means the area in the immediate
vicinity of the production and distribution facility;
designed to ensure reliable operation and to protect life,
health and property of people.
Protective zones are protected by overhead lines,
underground lines and electrical substations.
3. Protective zones of electrical
equipment
Protective zone of overhead lines
Is defined by vertical planes along both sides of the lines at a horizontal
distance measured perpendicular to the lines that makes the outer
conductor lines on each side.
In the protective zone of overhead lines is
prohibited, among other things:
• construct buildings,
• place constructions,
• store flammable or explosive substances.
Voltage
Dimension of zone
nad 1 kV do 35 kV
7m
nad 35 kV do 110 kV
12 m
nad 110 kV do 220 kV
15 m
nad 220 kV do 400 kV
20 m
nad 400 kV
30 m
4. First aid for electric shock
General procedure for the provision of first aid
Every action in the implementation of first aid must be meaningful,
purposeful, calm and resolute.
The speed of implementation cannot endanger an injured person.
Proposed procedure
1. Ensuring safety of both a injured and a rescuer
•
switch off electric current;
•
extinguish fire;
•
towing away of injured person in explosion hazard;
•
eliminate other negative threats (eg. Gas).
4. First aid for electric shock
2. Examination of an injured person
•
examine respiration, blood circulation, and state of consciousness;
•
in the case of heart failure immediately begin the resuscitation;
•
communicate with injured person; questioning on pain, ability to move
with limbs etc
•
assess the overall condition - facial expression, discoloration of the
lips, nail beds perfusion;
•
measure the pulse and watch its character.
3. Providing of First Aid
Prior to the beginning of First Aid, we must firstly determine the character of
damage:
•
vital functions are not damaged - less serious states.;
•
vital functions are threatened - it is acute immediately life-threatening
states;
•
sudden breathing and blood circulation failure requires an immediate
start resuscitation.
4. First aid for electric shock
4. Report for Ambulance Service and Police
•
What?
•
Where?
•
When?
•
How many injured people?
•
How serious are the injuries?
•
Who reports and contact of reporter.
5. Conclusion
Protection of generators against electric shock
Single-phase generators
The protection system of single-phase generator is grounding in an
isolated system and connecting all metal parts that may come under current.
The metal parts of generators, beyond the outer protective frame, are
connected with grounding elements of outgoing plugs.
Three-phase generators
Three-phase generators are equipped with selector of protection
against touch voltage mounted in switchboard.
Selector of protection allows setting following ways:
a) grounding in isolated systems;
b) neutral;
c) voltage protector.
References and further reading:
1. NEHODA, J. (S - 3177) Elektrotechnické prostředky ženijního vojska
a ochrana před úrazem elektrickým proudem. Vyškov: VVŠ PV, 2000;
2. Vyhláška č. 50/1978 Sb. O odborné způsobilosti v elektrotechnice;
3. Vševojsk-16-8. Bezpečnostní
předpis pro elektrická zařízení
v pojízdných nebo převozných prostředcích pozemní vojenské
techniky. Praha: MO ČR, 1999.
List of tasks for students:
1.
2.
3.
Briefly describe the possibilities of protection
against electric shock.
Generally characterize protective zones of
electrical devices.
Describe activities in provision of First Aid for
electric shock.