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daily online feature, “Code Question of the Day.”
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Code Question Of The Day
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Friday, July 03, 2009
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Subject: Article 517 Section 517.30(C)(3) (5)
I am currently designing the electrical system in a patient care area. Article 517.30(C)(3)(5) exempts metal raceway for nurse call, telephone/data wiring and other secondary circuits of class 2 or class 3 communication or signaling system.
Can the Nurse call wiring and telephone/data wiring be run in the same sch 80 PVC conduit and stubbed 6" above ceiling and use cable tray or J-hook on the ceiling to the system distribution board?
Thank you
Alberto
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code question and answer:
Thursday, July 02, 2009
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Subject: Re: Code Question of the Day - April 22, 2009
Charlie,
Thanks for your interpretations of the code. Regarding 250.32B, if a equipment grounding conductor is to be used for grounding and bonding the equipment etc and all you have is a pedestal for an RV, what are you supposed to do with the installed grounding conductor from the ground rod if its not supposed to be connected . I'm confused?
Jim Wendt
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Answer:
Hey Jim, thanks for participating.
The grounding electrode conductor from the grounding electrode is connected to the ground bus in the panel. It is the grounded (neutral) conductor that is not connected to the panel enclosure. The GEC is connected to the equipment grounding terminal bus in the enclosure but the neutral bus is not connected to the panel enclosure. This means that the green screw is not used to tie the neutral bus to the enclosure nor is a jumper connected between the ground bus and the neutral bus.
If the equipment-grounding conductor and the grounded (neutral) conductor are connected together a parallel path for neutral current would be established on the equipment-grounding conductor.
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Section: 250.32(B), 250.24(A)(5), 550.33(A)(2)
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Source: Charlie Trout
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ANSWERS: Answers are the author’s opinions and do not represent formal interpretations of the National Electrical Code.
All answers are based on the latest edition of the NEC, unless the question requests a response based on a specific edition.
CONTACT US: To submit a question, subscribe to Code Question of the Day, or remove yourself from this list, please send an e-mail to
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ABOUT THE AUTHOR: Charlie Trout is a nationally-known NEC expert and author. He served on three different National Electrical Code-Making Panels and is past chairman of CMP-12. He is also a member of the NECA Codes & Standards Committee. In 2006 Charlie Trout won the prestigious Coggeshall Award, given to recognize outstanding contributions to the electrical contracting industry in the technical and training area.
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