OT: Electrical Service Question

We have a panel that one of our contractors built and we have not installed it yet.

The panel has a smaller panel mounted to the right hand side that is housing the 400 amp disconnect and they made 3 holes and installed 1 inch cord connectors (1 for each phase)to pass the power into the distribution block of the control panel.

The cord connectors are about a half inch apart. One of our older electricians said we needed to change this as the phases being seperated like that and running though 3 different cord connectors would produce eddy currents and heat up in that area? Is this true? How big of a problem is it?

Our electrician suggesed changing it to use 1 large cord connector for all 3 phases. Each phase is DLO cable coming from the lod size of the disconnect.

Hi Tim, are you the boss. If you are an electrician you should know most of these answers, start to take control of that responsibility instead of raising every question on this site. Yes eddy currents can be a major issue and cable insulation around the gland area can be melted OFF. 3 phase cables in tree foil config going thru a non ferrous gland plate, with high current will result in failure. Change to a non ferrous gland plate or install one, or gut a line between the phase holes, then Promote your electrician to your position as you seem to struggle with basic electricity.

I don't know what sort of current your system will use but yes it could be a problem and the heating could easily be bad enough to melt the insulation and cause a fault. The easiest way of preventing this would be to use a hacksaw to create slots between the holes so eddy currents cannot circulate. These can be sealed with a non conducting sealant if you need to maintain a high IP rating. Cutting a hole and fitting a non ferrous plate to house the connectors would be a better job.

I think it would be better to not answer the question(incorrectly, I might add), than to be condescending and insulting.

If it is me you are replying to, please correct me in what should be done?

You state non-ferrous in both situations. I know it is just a typo, but I had to give you a hard time about it.

what part of non- ferrous is incorrect and please explain were my answer is incorrect?
I am not the best speller even with spell check, but l have just had a confirmation with WIK and it seems right. Please correct me regarding eddy current and how YOU would rectify the issue?

You state that going through a non-ferrous gland plate will cause a problem, so he should change it to a non-ferrous gland plate.

duckman said:

Yes eddy currents can be a major issue and cable insulation around the gland area can be melted OFF. 3 phase cables in tree foil config going thru a ferrous gland plate, with high current will result in failure. Change to a non ferrous gland plate or install one, or gut a line between the phase holes.

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Corrected

I bow to your wisdom, it was not a typo it was a back to front failure. That said all else remains! I re read what l wrote and did not see my mistake BUT! in the field l would not be asking these questions and what l have stated when you read all his other posts still remains.
Condescending/insulting? I'm not the one that doesn't know. SOME OLDER ELECTRICIAN, maybe he knows something without having to goggle it,?

That seems like a weird way to do it. I would tend to agree with your electrician. How big are the wires themselves? Are you pulling 500MCM wires or is the rating of the panel just ove 200A? Even so, A nice big LB would probably be your best bet.

Not that you asked, but I'm curious, did they put a lock solenoid on the door? I would hope they have some means of protecting the enclosure from being inadvertently opened with power on, especially with a 200-400A service.

Every post on this site comes from someone who doesn't know something. That is the purpose of this site.

Highland Controls said:

Every post on this site comes from someone who doesn't know something. That is the purpose of this site.

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I would rather someone ask a question than pretend to know the answer.

Tim,

in my opinion, this is not legal.
a cord connector surrounds the wire 100% which to me is in violation of the fill rule.

eddie currents will be a problem and therefore you should use a single pipe.

the type of wire used, length of the pipe, size of the wire, room temperature, number of conductors all play a role in how you do the installation.

i am also in agreement with duckman, and i am not trying to slam you. from your posts, what is your role in your company?

i say this because you are asking us questions that you should already know. you are at your facility and we are from around the world trying to help.

Eventually, you will ask us a question and we will answer to the best of our ability. Unfortunately, there will be some translation problems and we will answer incorrectly.

You need to become well versed in the following:
NFPA 70 National electric code.
NFPA 70E Arc Flash.
NFPA 79 Electrical standards for industrial machinery.
NFPA 496?? Purging and pressurization of electrical enclosures.

37 years of wiring, electrical design, control design, plc programming, industrial installations, and project management.
and i still need to keep studying to stay on top of things.

regaeds,
james

If you can open the door without disconnecting, you will need to redesign the panel.
The plate must be fireresistant, not conducting or magnetisable , etc.
Do not forget to ground properly, both boxes.