#4/0 Wire in a 125A panel

[l3city]

Hi fellas, here is another one for ya' all. Recently a customer came by and asked me if we can have #4/0 in a 125A panel. The reason for this is that this panel is far away from the service entrance section (SES) and the wire needs to be oversized to account for voltage drop. There can be other options such as coming with a xfmr before the panel, but the design admits no changes and that panel will be feed from the SES using this long long distance and this wire.

The electrical contractor told me he is bidding on this and that the electrical equipment supplier told him there is no way to insert a #4/0 into this (125A)panel by no means.
In my opinon I think one way to do this is to splice the #4/0 with a 125A rated wire before coming into the panel, so he can connect to the panel with no problems (please tell me if this can be done, this is just a guess for now).

But a more reasonable solution to this is the fact that I was thinking that there were some other types of connectors or lugs, that could replace the 125 lugs (as long as it is equipment compatible of course), to facilitate the connection of "bigger" wires into the panel. Can this be done?

I'll look forward for your responses
Thanks:smile:

 

[bphgravity]

This is a product standard issue and will not be covered by the NEC.

The manufacturer will identify the min and max and # number of conductors that can terminate at that panel lugs on the panel label or on the lug itself. Lug adaptors or other lug accessories are usually available for most panelboard styles and ratings. Again, you must check with the manufacturer.

 

[charlie b]

In my opinon I think one way to do this is to splice the #4/0 with a 125A rated wire before coming into the panel, so he can connect to the panel with no problems (please tell me if this can be done, this is just a guess for now).

Yes that can be done. Yes it is not an "elegant" solution. If the manufacturer has an available replacement lug that can take the 4/0, that would be the best bet.

 

[kingpb]

They make cable reducers that are essentially crimp on pins, that are made for exactly this type of situation.

The ILSCO #4/0 AWG is reduced to a #2/0 AWG without loosing ampacity. If this is a MLO panel then to actually have a 125A rating, it should be able to take #2/0. The Cutler Hammer panel for 150A is actually good for 225A, so it would have no problem taking a #4/0.

If it has a 125A main, the main should also be able to accomodate the #4/0. Might want to check around on the panels/mains before deciding what to do.

 

[petersonra]

They make cable reducers that are essentially crimp on pins, that are made for exactly this type of situation.

The ILSCO #4/0 AWG is reduced to a #2/0 AWG without loosing ampacity. If this is a MLO panel then to actually have a 125A rating, it should be able to take #2/0. The Cutler Hammer panel for 150A is actually good for 225A, so it would have no problem taking a #4/0.

If it has a 125A main, the main should also be able to accomodate the #4/0. Might want to check around on the panels/mains before deciding what to do.

I have used these before. Pretty slick way of dealing with this kind of problem.

 

[infinity]

If the load calculation calls for <125 amps why not simply use a 200 amp panel and main CB?

 

[LarryFine]

I think one way to do this is to splice the #4/0 with a 125A rated wire before coming into the panel, so he can connect to the panel with no problems.

If I did this, I'd make the splice within the panel, not external to it, leaving enough free conductor to reach lugs directly, just in case the panel is ever upsized.

 

[mdshunk]

I've tended to just H-tap on a short piece of whatever the MLO or MB will accomodate. I don't have the right dies for a cable reducer pin, and they aren't readily availble to me anyhow. I also bump into this when feeding things like parking lot lights with #4 or #6, when the breaker will only accomodate up to a #10. Just tap on a short piece of whatever the breaker will accomodate.