ungrounded systems

[geraldkinen]

This is another question that I can't find in the good book!
Ungrounded alternating current systems operating at not less than 120 volts and not exceeding 1000 volts shall have:
A)nonmetalic raceways for parallel feeders
B)metal raceways for all conductors
C)ground detectors installed on the system
D)ungrounded systems are not permitted

I chose D)

 

[iwire]

Well I would not have chosen D but the answer should be able to be found around 250.20 to 250.30

 

[charlie b]

Which "good book" are you using? If it is the 2005 NEC, you won't easily find the answer. The requirement did not change from 2005 to 2008, but the way it is worded did change. The words in your question are taken right out of the 2008 version. The correct answer, choice "C," can be found in 250.21(B).

If you are using the 2005, look at 250.21, in the paragraph after sub-article (4), and in the exception that follows.

This was a tricky one!

 

[LarryFine]

The correct answer, choice "C," can be found in 250.21(B).

Charlie! :roll: