Electrical Revision questions

What is the first action to take after discovering an accidental fire on a construction site?

• Ring the HSE.

• Raise the alarm.

• Smother the flames.

• Find an extinguisher.

Which instrument is required to carry out Safe Isolation?

• Loop Impedance Tester.

• Low Resistance Ohmmeter.

• Approved Voltage Indicator.

• Insulation Resistance Tester.

Which substance would require specialist licenced removal if found during a building demolition?

• Cement.

• Gypsum.

• Plywood.

• Asbestos.

What is the maximum voltage to earth of a single-phase reduced low voltage supply used on a construction site?

• 55 V

• 110 V

• 230 V

• 400 V

Who is responsible for working out estimates for materials using a building design?

• Client.

• Architect.

• Clerk of works.

• Quantity surveyor.

What unit is equivalent to V x 10^-3?

• MV

• kV

• mV

• µV

What is the cross-sectional area for the conductor shown in Figure 1?

• 6 mm²

• 10 mm²

• 16 mm²

• 25 mm²

Transpose (I_b / sqrt(3) * V_L * Cosθ) to make V_L the subject.

• V_L = P / (sqrt(3) * Cosθ * I_b)

• V_L = sqrt(3) * Cosθ * (P / I_b)

• V_L = (sqrt(3) * Cosθ * P) / I_b

• V_L = I_b / (sqrt(3) * Cosθ * P)

Which is a formula for calculating power?

• P = I^2R

• P = P / R^2

• P = VR^2

• P = V / 2

A hot water cylinder is 1.4 m high and 0.45 m in diameter. What is the maximum volume of water this cylinder can hold?

• 0.11 m³

• 0.22 m³

• 0.44 m³

• 0.89 m³