FREE Licensed Electrical Contractor Grounding and Bonding Questions and Answers Flashcards
6 cards from real Licensed Electrical Contractor practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 FREE Licensed Electrical Contractor Grounding and Bonding Questions and Answers flashcards as text
What is the minimum size copper grounding electrode conductor required for a 400-ampere service per NEC Article 250?
Answer: 1/0 AWG
NEC Table 250.66 requires a minimum 1/0 AWG copper grounding electrode conductor for services up to 500 kcmil.
When a metal water pipe is used as a grounding electrode, it must be supplemented by an additional electrode unless the pipe meets which condition?
Answer: No supplemental electrode is ever required with metal water pipes
NEC 250.53(D)(2) always requires a supplemental electrode when using a metal underground water pipe as a grounding electrode.
What is the maximum resistance to ground permitted for a single ground rod before a supplemental electrode must be installed?
Answer: 25 ohms
Per NEC 250.53(A)(2), a single rod electrode must have a resistance of 25 ohms or less, otherwise a supplemental electrode is required.
In a commercial building, where must the bonding jumper for a metal raceway containing service-entrance conductors be connected?
Answer: At each end and at every pull point
NEC 250.92(B) requires bonding of service raceways at each end and at all intervening points where access is available.
What type of connection is prohibited for grounding electrode conductor splices unless it is an irreversible compression type?
Answer: Wire nut connectors
NEC 250.64(C) prohibits splicing grounding electrode conductors unless the splice uses irreversible compression connectors, exothermic welding, or listed connectors.
According to the NEC, what is the purpose of an equipment bonding jumper on the supply side of a service?
Answer: To ensure an effective ground-fault current path for overcurrent device operation
Supply-side bonding jumpers ensure a low-impedance fault current path so that overcurrent protective devices can quickly clear ground faults.