Concentric for neutral?

[Open Neutral]

We are getting open delta 240/120 3ph. at a residence. The PoCo is feeding (1200 ft) a 25/10KV duplex transformer with two "1/0A EPC CONC ENC PE" runs from their 3ph 22KV P-P pole run.

A local HV contractor {& retired PoCo employee} stated there should a bare neutral run also, as depending on the concentric sheath for the current-carrying neutral is a bad idea. I've also been told that by others.

How common is this approach? Should I be concerned? In theory, when/if the cables fail, it's their problem...but my client would be burning propane for many days before ever they fixed such. And open neutrals worry me.

 

[Smart $]

...

A local HV contractor {& retired PoCo employee} stated there should a bare neutral run also, as depending on the concentric sheath for the current-carrying neutral is a bad idea. I've also been told that by others.

...

In the case of 1? or full-boat 3?, I surmise it is common. But in the case of powering an open-delta system, I agree it is a bad idea.

 

[Open Neutral]

In the case of 1? or full-boat 3?, I surmise it is common. But in the case of powering an open-delta system, I agree it is a bad idea.

The previous single-phase plan called for a sole 1/0, again no neutral.

I suppose we could beg for same, but we'd be charged even more than the now-$53K pricetag.

 

[Hv&Lv]

We are getting open delta 240/120 3ph. at a residence. The PoCo is feeding (1200 ft) a 25/10KV duplex transformer with two "1/0A EPC CONC ENC PE" runs from their 3ph 22KV P-P pole run.

A local HV contractor {& retired PoCo employee} stated there should a bare neutral run also, as depending on the concentric sheath for the current-carrying neutral is a bad idea. I've also been told that by others.

How common is this approach? Should I be concerned? In theory, when/if the cables fail, it's their problem...but my client would be burning propane for many days before ever they fixed such. And open neutrals worry me.

Are you sure the specs in parenthesis are correct? I have used alot of 1/0 EPR, but can't place EPC. All of our URD cable is full neutral, and as such should be fine.Their engineers should have more sense than to supply shielded cable for this application. Concentric neutral cable should be used, and this may be what this is.

 

[Open Neutral]

Are you sure the specs in parenthesis are correct? I have used alot of 1/0 EPR, but can't place EPC. All of our URD cable is full neutral, and as such should be fine.Their engineers should have more sense than to supply shielded cable for this application. Concentric neutral cable should be used, and this may be what this is.

Here's all I know; courtesy of the print:
{attached}

Hope it's legible; a PDF was too big. That's the pole line visible in the upper section.

 

[Hv&Lv]

Here's all I know; courtesy of the print:

Hope it's legible; a PDF was too big. That's the pole line visible in the upper section.

That cable is fine. It is 1/0 aluminum conductor, with a concentric neutral (more than likely full) encapsulating polyethylene jacket. With a full neutral on each cable, the two cables will have 2-#2 copper neutrals.

Here is an example :http://www.kingwire.com/ecomm/inv/s...-AL+345TRX+16X14+JK&file=A10-01UD35GT000J.htm

 

[Open Neutral]

That cable is fine.

Thanks. With everything else wrong with the project, I'm glad this can be marked off.