Ground Rod Needed, Yes

[don_resqcapt19]

I'm not looking to add a GE, I do not have anything but a grounding conductor in the feed to the transformer itself.
It is a 480 volt single phase (two hots and a grounding conductor) to 240/120 volt single phase 15 KVA transformer/panel (a combo unit). The only grounds in the transformer is the grounding conductor from the feed to the transformer and the branch circuits that feed out of the panel to the lights and outlets.

You don't have a choice, a grounding electrode is required for the secondary side of this transformer.

 

[CCCI]

Power Zone

Power Zone

The simplest way to do this job is to use a Sq D Mini Power Zone, its a primary-transformer-secondary panel all in one.
Three wires on the primary, 2 ground rods and you are done.

That is what this is. This one is just made by General Electric (G.E.) It is a 15 KVA transformer/panel combo unit. The electrical contractor is just telling me that I do NOT need a Ground Rod and I say that I DO need a Ground Rod. I just wanted some back-up from this forum because they think that we do Not need a grounding electrode.

 

[petersonra]

That is what this is. This one is just made by G.E. It is a 15 KVA transformer/panel combo unit. The electrical contractor is just telling me that I do NOT need a Ground Rod and I say that I DO need a Ground Rod. I just wanted some back-up from this forum because they think that we do Not need a GE.

You need a GE. If you decide to use a rod because one of the two specified GEs is not available, you will probably need to install two.

 

[CCCI]

Yes!

Yes!

You don't have a choice, a grounding electrode is required for the secondary side of this transformer.

Thanks all of you for your help. It seems that most of us agree that this transformer needs it own GE because it does not have anything but a grounding conductor going to it in its feed.
I just needed some back-up because the electrical contractor thinks that it is fine without a GE.
Thanks again to all that have written me.

 

[don_resqcapt19]

Thanks all of you for your help. It seems that most of us agree that this transformer needs it own GE because it does not have anything but a grounding conductor going to it in its feed.

It doesn't really have anything to do with the primary feed. It needs a grounding electrode because it is a SDS and 250.30(A)(7) requires it.

 

[petersonra]

It doesn't really have anything to do with the primary feed. It needs a grounding electrode because it is a SDS and 250.30(A)(7) requires it.

In his last post, the OP used the phrase "own GE". That implies to me that he feels it can't share a GE with the existing structure so one has to be added.

I think that is not correct in most cases. Building steel is often the GE used by an SDS and it is often the same building steel the electrical system is already grounded to. No need to install rods.

In his specific case, it appears he may not have a practical connection to an existing GE, so installing ground rods makes sense.

BTW, what prohibits one from using the EGC that is already bonded to the GE as your GEC for an SDS, if it is adequately sized?

 

[don_resqcapt19]

BTW, what prohibits one from using the EGC that is already bonded to the GE as your GEC for an SDS, if it is adequately sized?

It is my opinion that you can do that when the transformer is in the same building or structure that the primary feed comes from. There are some issues as far as compliance with 250.64(C) and (E).

 

[CCCI]

No Existing GE

No Existing GE

In his last post, the OP used the phrase "own GE". That implies to me that he feels it can't share a GE with the existing structure so one has to be added.

This panel is off by itself. It has no GE of any type near it. It is a Transformer/panel conbo unit outside on a post. No water pipes, no building steel and no existing GE. A gazebo will be about 50' from the taransformer/panel, but the gazebo itself will not have power on it.

 

[petersonra]

This panel is off by itself. It has no GE of any type near it. It is a Transformer/panel conbo unit outside on a post. No water pipes, no building steel and no existing GE. A gazebo will be about 50' from the taransformer/panel, but the gazebo itself will not have power on it.

put in a couple of rods and call it a day.