Determining proper Ground in warehouse electrical system

[SRK]

Hello, I have been searching this topic for an answer to a question about proper grounding of a home/warehouse. I couldn't find anything that precise, so I need to ask...and hopefully this gets worked out.

I am concerned whether I need to attach the Grounding Bar to the Neutral Bar in my Main Circuit Panel. In my warehouse, the electricity comes through the meter, and at the bottom of this tall Meter Enclosure is a pipe (coming out the side) that attaches to a metal Water Pipe (which is the Main Ground, I believe). Next in the path of electricity is a electrical box that splits the incoming electricity to two electrical circuit panels (one 240/120v and one "Wild Leg" system). The Main Circuit Panel I am concerned with is the 240/120v panel which controls most of the lighting, appliance and outlets in my warehouse (the Wild Leg is at the other end of my warehouse and once used for lathes, grinders, etc...and is a whole other story...). So, in this Main Circuit Panel, the Ground Bar IS NOT ATTACHED to the Neutral Bar, and I fear that this means I have no proper ground for grounded circuits in my warehouse (and, there are no green/ground electrical wires in the Main Circuit Panel anyway, which leads me to believe that all the three-pronged outlets in this warehouse are not properly grounded to begin with!!).

My questions is: should I connect the Grounding Bar to my Neutral Bar? I ask this because I want to add recessed lighting to my kitchen which requires a proper grounding of the system, and I wondering if I should ground the new system within my Main Circuit Panel or whether I should ground the system directly to a water pipe within my warehouse? All the other electric lines are only Hot/Neutral, and since I am working with Romex and 12/2 cable, I'm unclear of the proceedure.

Thank you in advance for your answer(s).

Best, SRK

[hallerb]

have you checked the existing 3 prong outlets with a circuit tester?

how old is the building / electrical system?

[SRK]

Hello, I have not tested the 3-prong outlets with a circuit tester. The building is from the 30's but the electrical system is much, much newer (I can't be precise).

SRK

[e-mail] wrote:

[dpb]

Not being able to see it from here :), I think your best bet would be to get an electrician to look at it.

If i was wired w/ x/3 and there aren't ground wires in the box, then there shouldn't be 3-prong outlets. I suppose there could GFI somewhere but can't see that, either.

[RBM]

If the box with the meter, also has disconnect breakers in it, that would be the location where the grounding and grounded conductors get attached together. All panels beyond that point become sub panels. In your case, one would be fed from the main panel with four wires, two hots, one neutral and one ground and the three phase panel would be fed with five wires, three hots, one neutral, and one ground. In both sub panels, the neutral buss and the grounding buss will be separate

[SRK]

Hello, I checked my Main Circuit Panel and the 3-phase panel boxes, they are 3 (two hot, one neutral) and 4 (3-hot, one nuetral) connectors respectively. Does this then mean that I SHOULD connect the Grounding bar to the Neutral bar...and in both sub-panels?

Thank you for the resp> If the box with the meter, also has disconnect breakers in it, that would be

[RBM]

I just now noticed that it appears you may be in the UK, in which case, disregard everything I've said. What I've described is how this is done in the US under the NEC. Keep in mind though that the "grounding" conductor does not come into the panel with the service conductors.

[SRK]

Hello, I am in the US, I just have a UK email address for Yahoo.

I still am looking for whether I should connect the Grounding Bar to the Neutral Bar within my Main Circuit Panel and any other subpanels, since none have a Ground cable/connector coming in from the Meter/Main Breaker.

-SRK

RBM (remove this) wrote:

[RBM]

No, in sub panels the neutral and ground busses are kept separate.

[John Grabowski]

It is possible that the metal conduit is being used as the main grounding conductor. In that case the ground bar is grounded and there is no need to install an additional grounding conductor.

[John]

Are there any wires connected to the ground bar? You said there are no green wires and no bare wires. This implies the ground bar is empty with no wires connected to it? So all circuits going out from the panel are two-wire cables? If this is the case, then what is the ground pin of all three-prong receptacles connected to?

This is not a likely scenerio (no grounding system but have 3-prong receptacles). Perhaps I misunderstood. The best thing is to post on some web space the photos of the panels involved.

Could the box that splits out 240/120v and 3phase already connect the ground and neutral together?

I suggest you not modify anything until it is absolutely clear what the situation is.

[SRK]

Hello, I checked inside the main breaker (where also the 240/120 and 3-phase split) and the Neutral and Ground cable are connected inside that box.

So, > >

[RBM]

In your sub panels you should have separate ground and neutral busses- not connected together. The grounds of your romex cables go to the ground buss and the neutrals to the neutral buss

[SRK]

Hello, Great. I understand and can apply the knowledge. Thank you very much.

-Steve

RBM (remove this) wrote: