AR15.Com Archives
 can i run a bare ground wire in steel conduit?
beerstud  [Team Member]
9/18/2007 3:21:52 PM EST
is this ok/
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swhitney  [Member]
9/18/2007 3:40:03 PM EST
I am a general contractor and not an electrician...

Running bare ground wire in a metal conduit is a waste of time, as the inevitable contact will render the two ground systems homogeneous.

The reason to run an insulated ground wire is to preserve the integrity of an isolated ground return run.

Isolated ground circuits, if intact and insulated through their run are beneficial in reducing noise and protecting electronic circuits.

If you are pulling wire through conduits, you should be pulling single strand individual insulated conductors. White, Black and Green.

This is the normal method of running a ground through metal conduit, and the only method suitable for PVC conduit.

Research: Isolated Ground Circuits

Edit: Relying on the metal conduit and its fittings (designed as housings and chase ways) for a grounding circuit is not advised. Industry standard is to use single strand insulated solid wire (green) within the conduit to transfer the faults down to the grounding plane.

Do not pull Romex through a conduit.
AR9mm  [Member]
9/18/2007 3:57:28 PM EST
I am not an electrician but Isn't the grounding {Equipment Grounding} (Green or Bare) the conductor which is not designed to be, except only on a momentary emergency basis, a current carrying conductor. This equipment grounding conductor is normally designed to carry the electrical fault [short circuit to metal] to mother earth {ground}. This causes the interrupting rating of an overcurrent device {fuse or breaker} to quickly de-energize the circuit. The short circuit would be when the metal associated to the electrical design has become energized which causes a hazard to personnel associated to that metal of the equipment. so wouyldn't the condiut and the ground wire the same?

I have seen it in many insallations to keep ground integrity in case of conduit seperation. Many of these were where metal flex is used.
Wheres-Waldo  [Member]
9/18/2007 5:21:22 PM EST
<~~~Qualified electrician

Any metal conduit or EMT should be grounded, regardless of what it contains.
When you walk into a big industrial ware house and look at all that conduit...its all grounded!
So yes, you can run a bare copper or aliminum ground wire through a conduit/ or PVC, within NEC specs

Oh by the way, the only reason you would want to preserve a specific ground from any other ground is if its on a seperate service...And still not needed

our company has wired 10 bank meter's (one big meter feeding the panels for 10 different complexs) with one continuitous (all grounds are connected in the meter and panel) ground. completly safe and within NEC spec's
AR9mm  [Member]
9/19/2007 3:53:16 AM EST
The projects that had the extra ground in the pipe were specified that way in the contract documents. My portion of the project was the fire alarm installation and it specified a ground wire in the flext connection between the ceiling j-box and the j-box mounted on the accoustical ceiling grid. Many of these connections get seperated from the constant work that goes on in those ceilings. With over 500 devices on this project some of these connections were bound to fail.

brickeyee  [Member]
9/19/2007 6:42:13 AM EST
“This equipment grounding conductor is normally designed to carry the electrical fault [short circuit to metal] to mother earth {ground}.”

Common misconception.
The current is trying to return to the source, normally the last transformer on the line.
For a 120/240 V system it is the center tap of the transformer.
For a 3 phase Y it is the common point of the windings.
For a 3 phase delta NOTHING happens.

The earth is not a very good conductor at 120/240 V, or even at 500 V.
You need at least a couple kV to drive much current.

The grounding on a service is for lightning protection and leakage from the primary side of the transformer (normally 7.2 kV or higher).
TheWind  [Team Member]
9/23/2007 4:30:30 PM EST
I was going over an outdoor subpanel with my Buildng inspector. He said the ground had to be seperate and insulated. Also not to have the outdoor fixtures ground to anything other than the main panel
Tango7  [Team Member]
9/23/2007 5:02:35 PM EST

Originally Posted By AR9mm:
The projects that had the extra ground in the pipe were specified that way in the contract documents. My portion of the project was the fire alarm installation and it specified a ground wire in the flext connection between the ceiling j-box and the j-box mounted on the accoustical ceiling grid. Many of these connections get seperated from the constant work that goes on in those ceilings. With over 500 devices on this project some of these connections were bound to fail.


Actually, the National Electrical Code (the Code) requires a separate grounding conductor, either bare copper or insulated (green or green w/ yellow stripes*) on Flexible Metallic Conduit (FMC/"Flex"/"Greenfield") because the Aluminum or steel armor has a much higher resistance than the current carrying conductors. Such a Grounding conductor should be attached to the device or j-box where the device is, and then to the j-box where the continuous path to ground (conduit) resumes.

* Some inspectors I've dealt with have allowed us to use white with green taped ends to indentify Grouding conductors for flex.
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