Exam

Purpose of the course

To give the basic knowledge of electricity - as much as to be able to recognize the danger of electricity and to avoid it

Electrical Qualification of persons

Ordinary Person; Instructed Person; Skilled person

Ordinary person

Person without any qualifications

Instructed Person

A person adequately advised or supervised by skilled person to enable him or her to avoid dangers which electricity may create

Skilled Person

A person with reevant education and experience to wnable him or her to avoid dangers which electricity may create

Threatening danger on electrical equipment

accident by electric current; fire; explosion

Every employee must get at least the lowest qualifications

according to government regulation No. 194/2022

Acquainted person

These are the employees (ordinary persons) acquainted with regulations on treatments with electric equipment and aware of the possible danger of electric current

Category of Voltages

Safety Extra Low Voltage; Extra Low Voltage; Low Voltage; High voltage

Safety Extra low voltage

a.c. < 25 V; d.c. < 60 V

Extra Low Voltage

a.c. 50 V to 1000 V; d.c. 120 V to 1500 V

High Voltage

a.c. > 1000 V; d.c. > 1500 V

Allowed Activities (operation) Part 1

1. They can independently manipulate only electrical equipment of a SELV; and low voltage but pnly if they cannot touch the live parts during a normal operation. 2. Switching on and off, plugging into the socket, moving connecting cables, exchange of bulb

Allowed Activites (operation) part 2

3. They can perform maintenance work without the dismantling with instruments (dry cleaning) when the equipment is switched off. 4. There must be a safe distance from unprotected working parts unfer voltage up to 1 kV at least 1 meter

Forbidden Activities Part 1

1. To repair electrical appliances and distribution network. 2. To work on parts of electrical equipment under voltage. 3. To use electrical equipment suspected of damage

Forbidden activities part 2

4. To move electrical appliances connected to the network (computers, calculators etc.) unless they are intended for such usage - (electrical hand tools) - unplugging of the socket. 5. To touch electrical equipment by wet parts of the body.

Live part

conducting part which js intended to be energized in normal use, including a neutral conductor

Exposed Conductive part

conductive oart of electric equipment, which can be touched and which is not normally live but which can become live when basic insulation fails

Basic Insulation

insulation of hazardous live parts providing the first protection against electric shock

Direct contact

contact with live parts

indirect contact

contact with exposed conductive parts, which have been become live under fault conditions

Operation

all activities necessary to permit the electical installation to function both under normal and abnormal conditions

Work activity

any form of work where there is possibility of an electrica hazard

Electrical work

work on, with or near electrica installation

Characteristic features of operation

Direct contact no; application of tools no; Duration of changes temporary

Characteristic features of work

direct contact yes; Application of tools yes; duration of changes permanent

Risk of common computer users regarding Health and Occupational Safety

increasing eye-strain (brightness, blinking); electromagnetic radiation; strain to the neck-spine

Safety work with computers

1. the worker at the screen shall have neither the light source nor its reflection in the range of view. 2. the brightness of the objects in the neibhourghood of the screen shall be balanced so as nor to produce big contrasts.

Safety work with computers part 3

if possible place a monitor in such way as to prevent the people from having access from its sides

safety work with computers 3

1. the placement of the keyboard: if sitting straight, the arms, placed with their palms on keyboard shall be perpendicular at the elbows. 2. the height of the seat: if the soles are fully tread-down on the floorc the legs shall be perpendicular at knees

Safety colours

red, blue, yellow, green

red color

prohibition - white sign with red circular band and crossbar text black

blue color

mandatory action - circular

yellow color

warnjng - yellow sign with triangular band

green color

information - rectangular

safety limits of steady electric current

threshold of perception ac 0,5mA, dc 2mA, charge 0,5uC; Threshold of pain ac 3,5mA, dc 10mA, charge 50uC; Let go current ac 5mA, dc 25mA

limit of selv at live parts

usual and wet conditions: ac 25V, dc 60V; Very bad conditions - -

limit of selv when not direct contact

usual and wet conditions ac 50V, dc 120V; Very bad condtions ac 12V, dc 25V

the highest permissible touch voltages

same as contact with live parts: a) permanently acting touch voltage; b) short-term acting touch voltage