Grounding and Bonding Flashcards

What is the minimum length a ground rod must be driven into the earth per NEC 250.53(G)?

Answer: 8 feet

NEC 250.53(G) requires ground rods to be driven to a minimum depth of 8 feet into the earth.

Which NEC section covers the main bonding jumper required at a service?

Answer: NEC 250.28

NEC 250.28 specifies the installation, sizing, and connection requirements for main bonding jumpers.

Per NEC 250.122, how is the minimum size of an equipment grounding conductor (EGC) determined for a branch circuit?

Answer: Based on the rating of the overcurrent protective device

NEC 250.122 Table sizes the EGC according to the rating of the circuit's overcurrent protective device.

Under NEC 250.92, what must be bonded together at a service?

Answer: All metal service equipment enclosures, raceways, and cable sheaths

NEC 250.92(A) requires bonding of all metal enclosures, raceways, and cable sheaths that enclose service conductors.

What is the function of a ground fault circuit interrupter (GFCI) in relation to grounding?

Answer: It detects current imbalance and trips even without a grounding conductor present

GFCIs sense a current imbalance between hot and neutral and trip regardless of whether a ground wire is present.

Per NEC 250.166, what is the minimum size copper conductor required as a direct-current (DC) system grounding electrode conductor for a large DC system?

Answer: Based on Table 250.166 using the largest ungrounded conductor size

NEC 250.166 uses a separate table to size DC grounding electrode conductors based on the size of the largest ungrounded DC conductor.

According to NEC 250.64(C), a grounding electrode conductor may be spliced only by which methods?

Answer: Irreversible compression connectors or exothermic welding

NEC 250.64(C) limits GEC splices to irreversible (compression) connectors or exothermic welding to ensure a reliable connection.