GROUND WIRE IN EMT CONDUIT

[wrldtravlr0612]

Here is the situation. I have a 5KVA system with a Voltage Regulator and a UPS. The system is powered from a Main Distribution Panel. The entire 5kVA system is bonded and grounded. The ground comes from the UPS Bypass switch and is terminated back at the ground in the Main Distribution Panel.
Here is my question.
Can I run the feeder wire from the Main Distribution Panel and the Ground wire from the UPS to the Main Distriution Panel in the same EMT Conduit?
It is my understanding that it can be done, as long as the Ground wire going to the Main Distribution Panel is bonded at the beginning of the conduit run and at the end of the conduit run.
Please help, I have 5 different people telling my 5 different things. If you could, please provide the NEC reference(s) also.

 

[roger]

Re: GROUND WIRE IN EMT CONDUIT

I'm not sure if I'm reading your question right, but I think your answer is in 300.3(B)

Roger

 

[wrldtravlr0612]

Re: GROUND WIRE IN EMT CONDUIT

Thanks for the response.
I was able to get more info to help explian the situation better.
This is a seperately derived system. Where the systme is bonded and then a ground is taken back to its source. Can this ground wire share the same conduit as the feeder wire? Please provide a reference for this.

 

[ryan_618]

Re: GROUND WIRE IN EMT CONDUIT

This is permitted. Perhaps you should be asking for a code reference that prohibits this practice.

Generally speaking, the code tells you what you are required to do and what you are not permitted to do. Not very often does it tell you what you are allowed to do. Think about it...if that were the case the book would be about 10,000 pages long trying to address every single item that you are allowed to do.

 

[wrldtravlr0612]

Re: GROUND WIRE IN EMT CONDUIT

Thanks for the timely response, then I guess the next question is:
Is there a code that will prohibit this in certain specific situations? Or, is there one that will prohibit this in general?
If there is such a code or codes, can you please tell me what it is or they are.

 

[roger]

Re: GROUND WIRE IN EMT CONDUIT

Since this is an SDS (see 250.30) we need to talk about the diference between the Equipment Grounding Conductor (EGC) and the required Grounding Electrode Conductor (GEC).

The conductor you are asking about is an EGC and must be run with the feeder conductors (there are some exceptions but not relevant here) per part six of article 250 starting with 250.110, as well as the aformentioned 300.3(B)


The GEC will be an additional conductor connected to an acceptable Grounding Electrode or Grounding Electrode System per part three of article 250 starting with 250.50.


Roger

[ April 08, 2004, 01:33 PM: Message edited by: roger ]

 

[dereckbc]

Re: GROUND WIRE IN EMT CONDUIT

A SDS requires that the nearest ground electrode be used. Per 250.30, in order:
1.Building steel
2. Water pipe within 5 feet of building entrance
3. Service electrode.
The ground bus in the MDP is not an electrode.

If the only availible ground electrode were the service electrode, I do not know of anything that would prevent you from using the primary raceway to get to the service electrode. If you did, you would have to bond the GEC every place where it entered and exited a metalic raceway or use PVC. You could use the conduit as the EGC per 250.118 for the primary feed, and use the void space for the GEC.

The code is funny when it comes to SDS. For example, if this UPS was a self contained plug and cord unit, no GEC would be required, the EGC would satify the safety requirements. But since the UPS is hardwired, it is required to have a GEC, go figure.

[ April 08, 2004, 04:41 PM: Message edited by: dereckbc ]

 

[don_resqcapt19]

Re: GROUND WIRE IN EMT CONDUIT

Dereck,
I believe that the Exception to (1)(2)(3) of 250.30(A)(4) may permit the use of the main serivce equipment grounding bus for this purpose. If this is the case, then it is my opinion that the primary circuit EGC can serve as both the primary EGC and the secondary GEC.
Don

 

[dereckbc]

Re: GROUND WIRE IN EMT CONDUIT

Don you may be right. I am going to have to read it a few times before I say yes or no. My first impression is the exception is for the plug and cord units I refered to earlier. Since I do not get to work with any units this small, I have not ever exercised this exception.

Hopefully Ron or Ryan_618 will chime in with their interpetation.

 

[websparky]

Re: GROUND WIRE IN EMT CONDUIT

Hi Don,

As far as I know, the last two systems we installed that have been hard wired, used the equipment ground bus in the service equipment enclosure. Both systems were scrutinized by two different State Inspectors.
That said, it did take a little convincing and manufacturers installation instuctions to be approved.