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Re: Voltage Drop on Neutral #61947 02/06/06 09:34 PM
Joined: Jan 2006
Posts: 4
S
Specialty Offline OP
Junior Member
The grounding is through the 1 rmc raceway w/ a grounding bushing at both ends. The poles also have a ground rod with the rod bonded to the pole. Perhaps the term "direct" was misleading or is there a reason the raceway cannot be used?


John
Work Gear for Electricians and the Trades
Re: Voltage Drop on Neutral #61948 02/06/06 09:50 PM
Joined: Oct 2004
Posts: 803
mxslick Offline
Member
One word: corrosion!

RMC directly buried will eventually corrode to the point of radically increasing it's resistance for the path as an EGC. You would then have high risk of creating voltage gradients as well. It would not be wise for either safety or economy to omit the grounding conductor.

Relying on raceway as a grounding path is poor practice anyway.

And welcome to ECN!!

edited typos

[This message has been edited by mxslick (edited 02-06-2006).]


Stupid should be painful.
Re: Voltage Drop on Neutral #61949 02/06/06 11:09 PM
Joined: Oct 2003
Posts: 156
D
dereckbc Offline
Member
John & iwire, IMO I do not think you would have to increase the EGC size if you only increase the size of the grounded circuit conductor. You have not change the size of the line conductor

Re: Voltage Drop on Neutral #61950 02/07/06 04:34 AM
Joined: Jan 2003
Posts: 4,391
I
iwire Offline
Moderator
Dereck I agree with you but I do not think that is what is happening here.

Check out my response.
Quote
If you run 8 AWG for the 'hots and neutral' you will have to run a 8 AWG EGC to comply with 250.122(B).

If the neutral alone was increased as is the case with much of the 'super neutral' MC we run the EGC can remain the size of the ungrounded conductor.


Specialty RMC can be used as the EGC per the NEC.

That aside I do agree with mxslick that for underground or outside runs it is better to run a 'wire' EGC.

I also would be running PVC in the ground but that is another personal choice. [Linked Image]

Bob


Bob Badger
Construction & Maintenance Electrician
Massachusetts
Re: Voltage Drop on Neutral #61951 02/07/06 05:58 AM
Joined: May 2002
Posts: 1,716
R
Roger Offline
Member
Specialty, thanks for clearing that up (that there will be an EGC) but I agree with Mxslick, at some time in the future the EGC will be lost due to corrosion.

I would do as Iwire and use PVC (my preference too) with a wire conductor for the EGC.

Roger

Re: Voltage Drop on Neutral #61952 02/07/06 09:41 AM
Joined: Jan 2005
Posts: 5,316
renosteinke Offline
Cat Servant
Member
Please note that the original poster said "parking lot lights." I suspect that these are HID type lights, and some folks will over-size the neutral out of a concern for "harmonics."

Of course, lots of times folks use terms like "harmonics" without having a clue as to what they mean; but making the wire larger is generally not a problem.

Re: Voltage Drop on Neutral #61953 02/07/06 05:45 PM
Joined: Apr 2002
Posts: 7,227
HotLine1 Offline
Member
Specialty:
Yes, welcome to ECN, and I have to say 'scuse me for omitting that above.

Again, PVC is my choice, but IF RGC, I would still install an EGC within the RGC.

I've seen quite a few specs recently for PL lighting with 3/4 x 10' rods (2) at each 'base', sonotube or pre-cast, and 'Cadweld" termination. The EE's say lightning protection, and a "redundant grounding system". I just assure that it is all bonded together, and 'to spec' in addition to NEC compliance.

John


John
Re: Voltage Drop on Neutral #61954 02/07/06 11:16 PM
Joined: Oct 2003
Posts: 156
D
dereckbc Offline
Member
iwire, sorry bout that. I should read more closely. Wished I never took that speed reading course. :lol:

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