H&S- 3-Safe isolation

What is the maximum voltage permitted for a low voltage circuit?

• 1500v

• 230v

• 1000v

• 400v

How many tests are required for single-phase isolation?

• 2

• 10

• 3

• 9

Answer explanation

For single-phase circuits there are 3 tests that should be carried out. These are as follows:

1.L-N

2.L-E

3.N-E

How many tests are required for three-phase isolation?

• 3

• 1

• 7

• 10

Answer explanation

For three-phase circuits there are 10 tests that should be carried out. These are as follows:

1.L1-L2

2.L1-L3

3.L2-L3

4.L1-E

5.L2-E

6.L3-E

7.L1-N

8.L2-N

9.L3-N

10.N-E

What Industry standard has information on the selection and use relating to test equipment?

• Guidance note 3

• GS38

• On-site guide

• Wiring regulations

Answer explanation

GS38 is a guidance document produced by the Health & Safety Executive dealing with electrical test equipment.

Three-phase voltage is rated at what voltage?

• 110v

• 230v

• 400v

• 1000v

Single-phase voltage is rated at what voltage?

• 230v

• 400v

• 110v

• 1000v