Electrician Services and Distribution 2

Question 1

What is a 'panelboard' as defined by the NEC?

Accepted Answer

A single- or poly-phase unit for controlling circuits by means of overcurrent devices

Answer

A panelboard is a distribution assembly containing overcurrent protective devices and buses that distribute power to branch circuits.

Question 2

What happens when a circuit breaker trips?

Accepted Answer

It automatically opens the circuit to interrupt overcurrent

Answer

A circuit breaker automatically opens to interrupt current flow when it detects an overload or short circuit condition.

Question 3

What is the purpose of a transfer switch in an electrical system?

Accepted Answer

To transfer load between two power sources such as utility and generator

Answer

A transfer switch safely switches electrical loads from the utility supply to a generator or alternate power source.

Question 4

What size copper conductor is typically required for a 100-amp service entrance?

Accepted Answer

2 AWG

Answer

A 100-ampere service typically requires 2 AWG copper service entrance conductors per NEC Table 310.16.

Question 5

What is the purpose of a neutral bar in a main electrical panel?

Accepted Answer

To provide a common connection point for grounded (neutral) conductors

Answer

The neutral bar provides a terminal block where all grounded (neutral) conductors connect to complete the circuit back to the source.

Electrician Practice Test