Professional competence in Professional competence in electrotechnics according to Act electrotechnics according to Act

50/1978 Coll.50/1978 Coll.

Workers instructed - §4(without professional training or experience,only within laboratory training at the FBMI,

not valid outside the FBMI)

Workers instructedWorkers instructed ( (§§4)4)-- without requirements for without requirements for

professional training or professional training or experienceexperience

were familiarized within the scope of their activities with the regulations for the operation of electrical devices by the organization,

were instructed in this activity,

were warned about the possible dangers of electrical devices,

were familiarized with the giving of first aid during electrical current accidents.

The danger of electrical The danger of electrical current accidents depends current accidents depends

mainly onmainly on::

the source voltage,

the current frequency,

the wave or pulse shape,

the duration of the current’s passing through the organism,

the current path through the body.

Symbology and signs in Symbology and signs in electrotechnics – the electrotechnics – the

meaning of safety coloursmeaning of safety colours

Symbology and signs in Symbology and signs in electrotechnics electrotechnics – – the safety the safety

meaning of geometric meaning of geometric shapesshapes

Symbology and signs in Symbology and signs in electrotechnics electrotechnics – – safety safety

notice examplesnotice examplesSign Safety sign

meaning

Symbol Supplementary sign

Notice examples

Restriction Electricity use

or electrical

device manipulation restriction

Lightning

bolt 1)

DO NOT SWITCH ON

DO NOT SWITCH ON – WORK IN PROGRESS DO NOT SWITCH ON – THE DEVICE IS BEING WORKED ON

Direction Directions for the correct operation of electrical devices

Lightning bolt

TURN OFF IN DANGER !

EARTH BEFORE WORK !

Warning Danger - electricity

Lightning

bolt

WARNING – ELECTRICAL DEVICE !

WARNING – LETHAL VOLTAGE !

WARNING – LIVE DEVICE

Information Safe or release state of the device

Lightning bolt

EARTHED

SHORTED

OFF1) 1) ČSN IEC 417ČSN IEC 417

Symbology and signs in Symbology and signs in electrotechnics – safety sign electrotechnics – safety sign

examplesexamples

Restriction sign

Direction sign

Warning signWarning sign

Information sign

What are safety signsWhat are safety signs oror

Help those afflicted by injuriesHelp those afflicted by injuries

http://ucjtk.ff.cuni.cz/publikace/12-04/tabulky.htmhttp://ucjtk.ff.cuni.cz/publikace/12-04/tabulky.htm

Symbology and signs in Symbology and signs in electrotechnics electrotechnics – – graphical graphical

symbols on electrical devicessymbols on electrical devices

Symbology and signs in Symbology and signs in electrotechnics electrotechnics – – labeling labeling conductors with lettersconductors with letters

Conductor label

English name Czech equivalent

L Line Conductor fázový vodič

N Neutral conductor střední vodič

E Earthing conductor uzemňovací vodič

PE Protective (+Earthing) conductor ochranný vodič

PEN PE+N = PEN conductor vodič PEN

Alternating current nominal Alternating current nominal voltage according to the ČSNvoltage according to the ČSN

Voltage up to 1 000 V

Grid: three-phase with an earthed node

Voltage over 1 000 V

Grid: three-phase with an isolated node

1979 1993 1979 1993

ČSN 33 0120 ČSN IEC 38

33 0120

ČSN 33 0120 ČSN IEC 38

33 0120

220 / 380 V 230 / 400 V 3 kV 3 kV

380 / 660 V 400 / 660 V 6 kV 6 kV

1 000 V 1 000 V 10 kV 10 kV

- - 22 kV 22 kV

- - 35 kV 35 kV

- - 110 kV 110 kV

- - 400 kV (400) 420 kV

MaximMaximum allowedum allowed electric electric current valuescurrent values

a steady electric current between parts that are touch accessible, flowing through 2000Ω of resistance, must never surpass

3,5mA A.C. or 10mA D.C.

Basic rules for working in Basic rules for working in ÚBMI ČVUT laboratoriesÚBMI ČVUT laboratories

max. 10 students per one assistant,the assistant must check the switching device before starting class work,the assistant must supervise the correct use of protective instruments,safety signs and notices are used in the laboratory, each student has gained professional competence (§4).

Protecting electrical circuits Protecting electrical circuits from short-circuiting and from short-circuiting and

overloadingoverloading

safety fuse x circuit breaker, use only appropriate and original fuses and circuit breakers, do not repair fuses and circuit breakers,perform the replacement only with unloaded parts.

Electrical and Electrical and electrotechnical device electrotechnical device

safety – protection classessafety – protection classes

Electrical and Electrical and electrotechnical device electrotechnical device safetysafety– – extension cordsextension cords

((policypolicy))

two core flexible cords with a plug without an earthing contact cannot be used for connecting class I. devices,extension cords used for extending power distribution from outlets must always be triple cored, flexible cords without a protective conductor with a plug without an earthing contact for class II. appliances must have their plug inseparably connected,

Regular check-ups and Regular check-ups and reviews of electrical reviews of electrical

appliances and hand-held appliances and hand-held electric toolselectric tools

hand-held electric tools,appliances divided into categories,dates set according to usage, protection class and category (for appliances),the protective conductor connection is checked,the insulation resistance is measured,the line supply cables are also checked and measured,standards and recommendations exist.

Important regulationsImportant regulations

ČSN EN 60601-1 Medical electric instruments Part 1: General safety requirements,

ČSN 33 0000 – 4 – 41 Electrotechnic regulations. Electric devices. Part 4: Safety. Chapter 41: Protection from electrical current accidents,

First aidFirst aid during electrical during electrical current accidentscurrent accidents

FREE the afflicted person from the electric circuit in a safe and suitable manner,find out if the afflicted person is conscious, breathing, has a tangible pulse, treat any wounds,if the afflicted person isn’t breathing, then apply mouth to mouth artificial respiration,if the pulse isn’t tangible, then apply indirect heart massage (BE CAREFUL about internal injuries),possible combination of both – call a doctor, but continue with resuscitation until the doctor arrives.

First aidFirst aid during electrical during electrical current accidents – clearing current accidents – clearing

airways (and respiration airways (and respiration check)check)

First aidFirst aid during electrical during electrical current accidents current accidents – – mouth to mouth to mouth artificial respirationmouth artificial respiration

((bending the head bending the head backwardsbackwards))

First aidFirst aid during electrical during electrical current accidents current accidents – – mouth to mouth to mouth artificial respirationmouth artificial respiration

((performingperforming))

First aidFirst aid during electrical during electrical current accidents current accidents – – stable stable

positionposition

First aidFirst aid during electrical during electrical current accidents – indirect current accidents – indirect heart massage (preparation heart massage (preparation

and principle)and principle)

First aidFirst aid during electrical during electrical current accidents – indirect current accidents – indirect heart massage (performing)heart massage (performing)