ELECTRICAL SCIENCE

ELECTRICAL SCIENCE & PRINCIPLES

Complete the following questions regarding basic electrical resistance:

Covering: Level 2 (2365-02) Diploma in Electrical Installations (Buildings & Structures) Unit 202. Level 3 (2365-03) Diploma in Electrical Installations (Buildings & Structures) Unit 302. Or EAL equivalent

Q1 A portable convector heater has a heating element that has a resistance of 17.7Ω and is to be connected to a standard 230V a.c. supply. Calculate the current flow when the heating element is switched ON.

Answer:

Q2 State the recommended rating of a non-rewireable BS1363 protective device suitable for the convector heater in question 1 above and state its location in the circuit.

Answer:

Q3 A fault occurs in an electrical distribution cable between the line conductor and earth. The resistance of the fault is 0.2Ω and the line voltage is 230V. Determine the fault current that is going to flow.

Answer:

Q4 Determine the total resistance for the string of resistors shown below.

2Ω

R1 4Ω

R2 6Ω

R3

Answer:

Q5 If a 120V supply is connected across the circuit shown in question 4, (a) determine the current that will flow and (b) the measured voltages (potential difference) across each resistor.

Answers: A:

Answers: B:

pd1 = pd2 = pd3 =