2391 Inspection & Testing Questions

OSG gives the maximum stable value of Ze for a TT installation as:

• 1660 ohms

• 600 ohms

• 200 ohms

• 100 ohms

Which type of earthing system relies on a separately supplied earth, usually the sheathing on the cable?

• TT

• TN-C-S

• IT

• TN-S

Which of the following would not be one of the human senses to use during the initial verification of an addition to a lighting circuit:

• Sight

• Hearing

• Taste

• Touch

On a standard TT installation, the result of the resistance of the earth electrode and the rated RCD residual operating current should not exceed:

• 25V

• 50V

• 110V

• 400V

Which of the following protection devices is unlikely to be suited for short circuit currents in the region of 6kA:

• BS 3036 semi-enclosed fuse

• BS 88-3 cartridge fuse

• BS 88-2 general purpose fuse

• BS EN 60898 circuit breaker

The term given to the person responsible for an electrical system is the:

• Competent person

• Electrician

• Duty holder

• Company manager

Regional electricity companies quote a maximum likely value of external loop impedance (outside the consumer's installation) for a TN-S system as:

• 0.35 ohm

• 0.8 ohm

• 21 ohm

• 200 ohm

EAWR states that working live is acceptable unless:

• Suitable tools are used

• Suitable PPE is worn

• It is reasonable in all circumstances for it to be dead

• An engineer gives you permission

Overloaded windings on a 3 phase motor may be identified in the first instance by using which sense:

• Sight

• Smell

• Touch

• Taste

Which of the following earthing systems has the path for earth leakage currents via the earth itself:

• TN-S

• TNC-S

• TN-C

• TT