Grounding and Bonding Flashcards

Under NEC 250.104, metal water piping systems in a commercial building must be bonded to which of the following?

Answer: Service equipment enclosure, grounded conductor, or grounding electrode conductor

NEC 250.104(A) requires metal water piping systems to be bonded to the service equipment enclosure, grounded conductor, or grounding electrode conductor.

What is the minimum burial depth for a ground rod electrode per NEC 250.53(G)?

Answer: 8 feet

NEC 250.53(G) requires ground rods to be driven to a depth of at least 8 feet to ensure adequate earth contact.

Which type of grounding electrode is considered a 'made electrode' under NEC 250.52(B)?

Answer: Ground rod

Ground rods (and ground plates/rings) are classified as 'made electrodes' under NEC 250.52(B) because they are installed specifically for grounding.

When is a main bonding jumper required in service equipment?

Answer: At every service disconnect enclosure

NEC 250.28 requires a main bonding jumper at each service disconnecting means to bond the grounded conductor to the equipment grounding conductor and enclosure.

Concrete-encased electrodes (Ufer grounds) must contain at least how many feet of rebar or wire?

Answer: 20 feet

NEC 250.52(A)(3) requires at least 20 feet of one or more steel reinforcing bars or bare copper conductors encased in concrete.

A supply-side bonding jumper is used in which location?

Answer: Between the service point and service disconnecting means

Supply-side bonding jumpers are installed between the service point and the service disconnecting means, on the line side of the overcurrent device.

What determines the minimum size of the grounding electrode conductor for a service using 4/0 AWG copper conductors?

Answer: Size of the service-entrance conductors per NEC Table 250.66

NEC Table 250.66 sizes the grounding electrode conductor based on the size of the largest service-entrance conductor or equivalent area.