At Your Service (Disconnect)

Although residential, commercial and industrial occupancies have traditionally been supplied by only one service, these days there are an increasing number of power sources present at these buildings and structures. Each occupancy served by a utility is required to have a service disconnecting means intended to cut off the utility power from the premises. The National Electrical Code has requirements specific to service disconnects, including essential rules addressing the number of services supplying a building.

1. Generally, each building or structure shall be supplied by ______ service(s).

One

Two

Three

An unlimited number of

Correct Answer: One

2. The term “utility” is not defined in the NEC, yet it is used in several Code rules.

True

False

Correct Answer: True

3. Generally, what is the maximum number of service disconnects permitted to be grouped in the same location?

One

Two

Three

Six

Correct Answer: Six

4. An on-site generator owned by the occupant is considered the electric service for the building or structure served.

True

False

Correct Answer: False

5. When the NEC specifies the grouping requirement for multiple service disconnecting means, all service disconnects must be “readily accessible from” and “in sight from” from one another.

True

False

Correct Answer: False

6. If conductors and equipment are under the exclusive control of a serving utility, the NEC does not apply.

True

False

Correct Answer: True

7. Which of the following represent conditions that would permit more than one service to supply a building or structure?

Special conditions, such as for a fire pump or emergency system

Capacity requirements

Different characteristics required, such as voltages, phases or frequencies

All of the above

Correct Answer: All of the above

8. The requirement for emergency disconnects applies only to one- and two-family dwelling units.

True

False

Correct Answer: True

9. If a service disconnect is installed outside a building or structure and is free-standing, the maximum distance from it must not exceed 50 feet.

True

False

Correct Answer: False

10. The distance service conductors are permitted to be routed inside a building to the service disconnecting means must not ______.

Exceed 10 feet

Exceed 25 feet

Exceed 50 feet

Be longer than that practical and nearest the point of entrance of the service conductors to the building or structure served.

Correct Answer: Be longer than that practical and nearest the point of entrance of the service conductors to the building or structure served.