Question about tying ground to neutral at transformer and upstream Main disconnect

[Installer]

Sorry if this question indicates a lack of fundamentals, but I only do Electrical design some of the time.
When I do it, I'm good at it, but when I stop for a few months and do "staff engineering" (*LOL") I forget everything
We have a 208 VAC 5 KVA transformer out in field with Two Hots and a Neutral tied to the Ground (established by a local counterpoise) fed by a Upstream Panel with a Main Disconnect,.
Should the Neutral supplying the transformer be tied to the the Ground at the Panel wit the Main Disconnect?

 

[hillbilly1]

It can be one or the other. Common practice though is at the transformer.

 

[texie]

Sorry if this question indicates a lack of fundamentals, but I only do Electrical design some of the time.
When I do it, I'm good at it, but when I stop for a few months and do "staff engineering" (*LOL") I forget everything
We have a 208 VAC 5 KVA transformer out in field with Two Hots and a Neutral tied to the Ground (established by a local counterpoise) fed by a Upstream Panel with a Main Disconnect,.
Should the Neutral supplying the transformer be tied to the the Ground at the Panel wit the Main Disconnect?

Why is there a neutral in the supply to the transformer?

 

[hillbilly1]

After re-reading the post, I thought the op was feeding a small panel on the load side of the transformer, but when Texie replied, I see what he meant.

 

[Installer]

I was told something like this. Is it correct?
If the neutral is connected to ground at more than one point, then the neutral and ground are connected in parallel between those two points. In accordance with Kirchoff’s laws, such connection makes the ground a current-carrying conductor under normal conditions!

 

[LarryFine]

I was told something like this. Is it correct?
If the neutral is connected to ground at more than one point, then the neutral and ground are connected in parallel between those two points. In accordance with Kirchoff’s laws, such connection makes the ground a current-carrying conductor under normal conditions!

Other than just earth, that's correct; no parallel neutral-current conductive pathway.

Either bond in the disco and run an EGC, or bond in the transformer and don't run an EGC.

Either way, the SDS still needs a qualifying connection to the building electrode system.

 

[Installer]

Now that Mr. Fine has weighed in, I feel safe.

 

[LarryFine]

Now that Mr. Fine has weighed in, I feel safe.

 

[winnie]

Wait. Please clarify exactly what you are doing.

You have an upstream panel with a main disconnect. The neutral is grounded there. A circuit feeds a transformer.

What is the voltage from the upstream panel?

What wires will feed the transformer?

What sort of transformer is it? Single phase, three phase? Delta:Wye or buck/boost or isolating?

What will the transformer supply?

You must not re-ground a source neutral.

You likely should ground a new neutral if the transformer creates one.

Jon

 

[electrofelon]

Wait. Please clarify exactly what you are doing.

I agree, I am still confused.

 

[LarryFine]

I also misunderstood the question.

We have a 208 VAC 5 KVA transformer out in field with Two Hots and a Neutral tied to the Ground (established by a local counterpoise) fed by a Upstream Panel with a Main Disconnect,.

Okay, I agree that the primary neutral should not connect to the transformer at all.

Should the Neutral supplying the transformer be tied to the the Ground at the Panel wit the Main Disconnect?

No, it should not connect to anything with a single-phase transformer.

You may be able to use it as an electrode for the secondary if needed.