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#34872 - 02/26/04 04:06 PM Equipment Case Grounding
sambroak Offline
Junior Member
Registered: 09/05/03
Posts: 5
Loc: Charleston, SC
I have been searching the NEC for the answer to the following:

The company that I am currently working for builds mobile communications suites. We use LEX Products connectors (camlock and bates connectors) for power and grounding. We purchase different equipment (radios, routers, etc) and mount it in Hardig cases. So is it necessary to ground the rack inside the case to an external grounding braid, block, etc. or does the ground in the equipment plug take care of it. I can't find anything in the NEC that addresses this unless I'm overlooking it.

Any help or NEC reference would be greatly appreciated.

[This message has been edited by sambroak (edited 02-26-2004).]
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#34873 - 02/27/04 01:55 PM Re: Equipment Case Grounding
CDN_ELECTRICIAN Offline
Member
Registered: 01/22/03
Posts: 73
Loc: Concord,Ontario,Canada
I don't know the exact rule but i believe that in your case as in many "All metallic electrical equipment must be bonded to ground), this would enclude enclosures.
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#34874 - 02/27/04 03:12 PM Re: Equipment Case Grounding
Bjarney Offline
Moderator
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
Two fundamental aspects of equipment grounding are..
  • Minimize voltage difference between exposed conductive surfaces
  • Facilitate rapid operation of overcurrent devices.

The NEC reiterates these concepts many times over.
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#34875 - 02/27/04 08:21 PM Re: Equipment Case Grounding
DougW Offline
Member
Registered: 06/08/03
Posts: 1143
Loc: North Chicago, IL
A little out of my area of expertise, but I'll offer my $.02...

The fact that your equipment mounts in a metal rack may be a clue...

If it's metal case screwed into place on a metal rack (bonded, as sorts), then I would think there may be an "equipment ground" terminal on the rack itself to connect to a grounding point.

But if all of the equipment is insulated, and each is provided with it's own grounding means ("grounded" / "3-prong" plug), then additional grounding should be unnecessary, IMHO

Of course, what if the metal cases for the equipment are also grounded - would these effectively ground the rack as well?

Does any of the literature that comes with your equipment discuss grounding? You may want to consult the manufacturer for additional info...

DougW, (mimicking the RCA Victor dog) staring perplexedly at the technology...
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#34876 - 02/27/04 08:35 PM Re: Equipment Case Grounding
sambroak Offline
Junior Member
Registered: 09/05/03
Posts: 5
Loc: Charleston, SC
First of all thanks to everyone who replied.

I may not have made it completely clear in my original post, the case itself is plastic, and the frame on the inside is aluminum supported in the middle of the case with rubber "shocks". All equipment that we use has a 3 prong plug so the equipment is grounded, I was just trying to get some facts on whether or not the mounting frame inside the plastic case needed to have a ground attached to it. There is no metal on the ouside of the case that contacts the frame in any way. In my opinion there is no need for grounding the frame inside the case, but I was trying to find hard facts in the NEC, but have still had no luck.

Once again thanks to all who have posted.
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