Question 5002 of 749 · Maryland Journeyperson Electrician Exam
A metal underground water pipe qualifies as a grounding electrode only if it is in direct contact with the earth for at least what length?
Exactly one answer is correct.
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Correct answer to question 5002
- B: 10 ft
Explanation
A metal underground water pipe must be in direct earth contact for 10 ft or more, including any metal well casing bonded to it, to qualify as an electrode. See 250.52(A)(1).
More questions: Grounding and Bonding
- 5003When a metal underground water pipe is used as a grounding electrode, what else does the Code require?
- 5004Under the general rule, interior metal water piping located more than what distance from its point of entrance may NOT be used to interconnect electrodes that are part of the grounding electrode system?
- 5005A concrete-encased electrode made of bare copper conductor must be at least 20 ft long and not smaller than what size?
- 5006A concrete-encased electrode must be covered by at least how much concrete?
- 5007A ground ring encircling a building must consist of at least 20 ft of bare copper conductor not smaller than
- 5008What is the minimum length of a rod or pipe grounding electrode?