# Reducing wire size



## Morg12345 (Jan 22, 2016)

This is actually from another post, I have a long run long run (275)of 250MCM, for a Residencial 200 amp service .Is it possible and code complaint to Reduce the last 40' to a 4/0 ser the breaker panel?...thanks...Morg


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## Slay301 (Apr 23, 2018)

Morg12345 said:


> This is actually from another post, I have a long run long run (275)of 250MCM, for a Residencial 200 amp service .Is it possible and code complaint to Reduce the last 40' to a 4/0 ser the breaker panel?...thanks...Morg


Why don’t you just get pins ?


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## Morg12345 (Jan 22, 2016)

Slay301 said:


> Why don’t you just get pins ?


Pins?
I didn't explain this a 100% they want to put in an addition with the full foundation onto the house .. they have to dig up the 250MCM conduit run ... Instead of redoing the whole thing for them I was wondering if I could just Make a spice and use 4/0 SER over to the panel...morg


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## SWDweller (Dec 9, 2020)

I do not like splices underground. I like splices with Al not at all under ground. 
I did splice feeders underground once in a vault. It filled with water periodically and in time the splices degraded. 
This is an odd installation for me. Where I live this run would be by POCO. 

I would want someone else of authority to make this decision.


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## splatz (May 23, 2015)

So you're thinking of going from a straight 250MCM shot 


```
=================================

to 

===============|| ||===============
               || ||
               || ||
               || ||
               || ||
```
with the branch off being 40' of 2/0 SER. 

Did you compare how much money this will this save versus pulling back the conductors to the branch-off point, running them to the new foundation, then running new conductors from the new panel to the original building? This way you have the full ampacity of the 250mcm to the first panel which gives you some flexibility for the future, no spices to worry about, and little question the inspector or power company will complain. Once you figure scrapping the 250MCM and avoiding the underground splices you might have just about paid for the extra wire. 

The pins @Slay301 was talking about are reducing terminals, you can crimp them on the 250MCM to reduce them to a size that fits in the lugs. I don't know what code rev you're on and whether you need an exterior disconnect. But if that's an issue, you might be able to go into a disconnect or meter-main with lugs that will take the 250MCM on the line side and the 2/0 on the load side into the first panel. There's probably a number of ways you could do it, although getting the equipment might be a challenge with the current shortages.


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