? been asked before, but not completely sure I understand. Where cable tray is not intended to be an equipment grounding conductor, but is mechanically continuously and attached to building steel structure which is bonded, is it considered bonded. is there still a requirement for an equipment grounding conductor?
grounding / bonding cable tray
- Thread starter DW98
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- Placerville, CA, USA
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- Retired PV System Designer
If "the cable tray is not intended to be an equipment grounding conductor", then by definition it cannot be counted as an EGC.
If you intend it to be an EGC and assure that all the conditions are met for it to be an EGC, then you can count it as an EGC and may not be required to also run a wire EGC. In some cases the NEC requires a wire EGC in addition to any raceway EGC.
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If you intend it to be an EGC and assure that all the conditions are met for it to be an EGC, then you can count it as an EGC and may not be required to also run a wire EGC. In some cases the NEC requires a wire EGC in addition to any raceway EGC.
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- Massachusetts
My read on this is that he does not want or need to use it as an EGC.
He just wants to know if it still needs to be bonded. I don't know the answer to that, I suspect yes.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
" is there still a requirement for an equipment grounding conductor?"
I don't see how you can justify your interpretation based on that sentence.
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- Mission Viejo, CA
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- Professional Electrical Engineer
Your suspicion is correct. It's a fundamental 250.4 requirement. You may have to dig a bit through the Subsections to determine which case applies, but basically, if it could become energized, it must be bonded. If I understand the OP description correctly, it sounds like it is.
- Location
- Massachusetts
I don't see how you can justify your interpretation based on that sentence.
Because I am fluent in electrian talk.
thanks for the replies. I've been rereading NEC 2008 392.7 (A) which references 250.96(A). I think instead of "is it considered bonded" in original post, I should have asked "it is considered grounded". I'm getting hung up on difference between grounding and bonding. If cable tray components are mechanically connected and the cable tray is then mechanically connected.to building steel which is connected to grounding electrode system, it is considered grounded?
I agree... but I've run across a couple AHJ's that insist on a bonding jumper. When challenged, they offer the following highlighted passage as "guidance" for their interpretation...
As you know, grounding "likely to become energized" non-current-carrying metal parts is to be done with the equipment grounding conductor of the circuit of which would do the energizing.
Yes... it is highly debatable. Is only bonding required or must it be equipment grounded. The requirements are ambiguous at best.
RichB
Senior Member
- Location
- Tacoma, Wa
- Occupation
- Electrician/Electrical Inspector
I would say that it is bonded to the grounding system.
Best, simplest, description I have heard was from Mike Holt when he once said--GROUNDING is done at one point--the point of service and goes to earth--BONDING is hooking everything else together and then to the grounding system at the point of service to provide a path for fault current
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