Electrical Installations: Fault Diagnosis and Rectification

What might cause a low voltage/voltage drop in an electrical installation?

• A high resistance joint or heavy load on the system

• A well-maintained circuit with no load

• A new and efficient switchgear

• A disconnected power source

What is a possible consequence of connecting too many pieces of equipment to a healthy circuit?

• The circuit will become more efficient

• It may cause overload or fault current devices to operate

• It will have no effect on the circuit

• The equipment will start to consume less power

What can a high resistance due to a loose connection cause?

• A decrease in voltage drop and reduced heat

• No change in voltage or heat

• A complete circuit failure

• A serious voltage drop and excessive heat

What is a possible consequence of insulation failure due to deterioration?

• Improved insulation performance

• Decreased electrical consumption

• Localised heating and a serious overcurrent

• Enhanced mechanical protection

What type of fault is characterized by a direct connection of negligible resistance between live conductors (line to line, line to neutral and line to earth)?

• Signal fault

• Insulation fault

• Short-circuit, open-circuit, earth fault

• Mechanical damage

Where can faults occur within the wiring system?

• Only in the wires themselves

• Only in the equipment/accessories

• Only in the instrumentation/metering

• In the wires, terminations and connections, and equipment/accessories including instrumentation/metering

What might cause excess current – overload in an electrical installation?

• Connecting too little equipment to the circuit

• Excessive mechanical loading or overcurrent machinery

• Proper insulation of conductors

• Low resistance in connections