Electrical Exam Help Quiz

What is the maximum disconnection time for a TNC-S final circuit with a nominal voltage of 230 volts AC and protected by a 32 amp circuit breaker?

• 0.2 seconds

• 0.4 seconds

• 0.6 seconds

• 0.8 seconds

What is the maximum permitted Earth fault Loop impedance for a reduced low voltage circuit with a nominal voltage of 55 volts AC and protected by a 20 amp type B BSEN 60898 circuit breaker?

• 0.39 ohms

• 0.65 ohms

• 0.26 ohms

• 0.52 ohms

What is the temperature limit under normal load conditions for an accessible part of equipment within arms reach that is intended to be touched but not handheld and is made of a non-metallic material?

• 90°C

• 80°C

• 70°C

• 60°C

What is the value of K for a 10 square mm copper conductor with 70°C thermoplastic insulation?

• 110

• 105

• 115

• 120

When identifying conductors by color, what color should the negative of a two wire Unearthed DC power circuit be?

• Red

• Black

• White

• Blue

What is the minimum value of insulation resistance for a circuit with a nominal voltage above 500 volts AC and tested at 1,000 volts DC?

• 2 megaohms

• 1.5 megaohms

• 1 megaohm

• 0.5 megaohms

What is the minimum cross-sectional area of a flexible cable for a caravan connection if the rated current is 32 amps?

• 4 square mm

• 5 square mm

• 7 square mm

• 6 square mm

What is the maximum permitted voltage drop in volts for a lighting circuit with a nominal voltage of 230 volts that is supplied from a low voltage installation supplied directly from a public low voltage distribution system?

• 7.5 volts

• 4.6 volts

• 5.2 volts

• 6.9 volts

What is the rating Factor ca for an Ambient Air Temperature of 40°C for a conductor with 70°C thermoplastic insulation?

• 0.92

• 0.87

• 0.97

• 0.82

What is the voltage drop per ampere per meter for a 70°C thermoplastic insulated and sheathed flat cable with protective conductor and copper conductors with a CSA of 6 square mm?

• 6.1 mV/A/m

• 6.7 mV/A/m

• 7.3 mV/A/m

• 7.9 mV/A/m