Grounding, Bonding & Neutral Conductors (NEC) practice test: free California General Electrician questions

Sample Practice Questions for Grounding, Bonding & Neutral Conductors (NEC)

1. Question 1Ref: NEC Table 250.66 — Grounding: Grounding Electrode Conductor Sizing

   A new residential service is being installed. What is the minimum size copper grounding electrode conductor required for a 200-amp service?

   A6 AWGB2 AWGC4 AWGD1/0 AWG
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   Correct Answer
   C. 4 AWG

   Table 250.66 sizes the grounding electrode conductor from the largest ungrounded service conductor. A 200-amp residential service typically uses 2/0 or 3/0 AWG copper, and for service conductors of 2/0 through 3/0 AWG the table requires a 4 AWG copper GEC. 6 AWG is only permitted for 1/0 AWG or smaller service conductors.

2. Question 2Ref: NEC 250.68(C)(1) — Grounding Electrode Conductor Connections: Metal Water Pipe

   A metallic water pipe enters a building and is bonded to the grounding system. How far from the building entrance must the bonding connection be made to the water pipe?

   AAt the main service disconnect onlyBWithin 10 feet of the pipe's entry into the buildingCWithin 18 inches of the water meterDWithin 5 feet of the pipe's entry into the building
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   Correct Answer
   D. Within 5 feet of the pipe's entry into the building

   The keyed answer is "Within 5 feet of the pipe's entry into the building". The bonding jumper to a metallic water pipe must be connected within 5 feet of the point of entrance into the building to ensure an effective ground-fault current path.