Unit 38 Multiple Choice Revision

What does Cg relate to in cable calculations?

Zs=

When calculating maximum Zs for a circuit design what is the 1.2 multiplier used to account for?

What is the maximum permissible voltage drop for lighting in a final circuit?

What is the formula for voltage drop?

What does In stand for?

If an RCD is to be for additional protection, how many tests should be carried out on it?

What is the rated current for an RCD that is to be used as additional protection?

What does maintenance factor in lighting design relate to?

Which out of the following relate to utilisation factor?

A room is to be illuminated to 350 lux. The maintenance factor is 0.85, utilisation factor is 0.8 and the room measures 6m by 8m. Calculate the number of fittings required if each fitting is 100W and has an efficacy of 70 lumens/watt.

What maintenance should be carried out on a motor to ensure correct working:

What types of earthing rely on the distributor's earthing arrangement?

How may PFC be obtained?

What earthing system has a combined earth and neutral conductor back to the transformer?

What is the maximum permitted voltage drop for a final power circuit?

A fault of negligible impedance between a live conductor and earth is known as?

How can earth fault loop impedance relate to the disconnection time of a circuit breaker?

It is acceptable to run single core cables on metal tray

It is acceptable to run single core cables in metal trunking

What is the most suitable containment method for an outside motor to be connected to the electrical supply?

What does Ci relate to in cable calculations?

An installation with a nominal voltage of 230V has an external loop impedance of 0.2Ω and an external line to neutral voltage of 0.18Ω. What would the PFC be recorded on the test certificate?

When measuring PSSC the earth should be removed from the installation.

When measuring PEFC your terminals will be connected between line, neutral and the earth bar.

Single phase circuit is run in trunking with 3 other circuits. The ambient temperature for the room is 35° . The design current is 33A and the protective device an MCB to BS 60898. What is the minimum size 70° single-core thermoplastic cable that can be used taking into account current carrying capacity only?

There are 7 x 10mm², 5 x 6mm², 4 x 25mm² and 8 x 2.5mm² single phase circuits to be installed in trunking. Calculate the size required if all cables are PVC BS 6004 cables.

A 5m run of conduit with 2 bends in it is to accommodate 2 ring final circuits of 2.5mm². Calculate the minimum size conduit to be used.

Electrocution doesn't always result in death

Which of the following should be included in a risk assessment

A store room must be illuminated to 200 lux. The size of the room is 9m x 10m, the room is kept fairly clean (M.F of 0.9) and due to god colour management and space ratios the U.F is 0.9. Calculate how many light fittings are to be used if each fitting contains 2 lamps of 2000 lumens each.