# 400Amp Underground Service



## yankeejoe1141 (Jul 26, 2013)

Why is the original EC not going to finish the job?


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## catsparky1 (Sep 24, 2013)

Why are you running 600 cu?


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## backstay (Feb 3, 2011)

What year code are you on?


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## JAElectrician2290 (7 mo ago)

yankeejoe1141 said:


> Why is the original EC not going to finish the job?


Dissapeared , said he was too busy


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## JAElectrician2290 (7 mo ago)

backstay said:


> What year code are you on?


2020


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## JAElectrician2290 (7 mo ago)

catsparky1 said:


> Why are you running 600 cu?


What would you run? I usually do parallel in 2 seperate conduits but this electrician ran 1-4” conduit


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## Dennis Alwon (May 9, 2009)

You can do the same think. Run 2 sets of conductors in the 4" and bring one set to Panel A and the other set to Panel B

This is not considered parallel because they don't begin and end together. Just make sure you size your conductors for the de-rating.


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## JAElectrician2290 (7 mo ago)

Dennis Alwon said:


> You can do the same think. Run 2 sets of conductors in the 4" and bring one set to Panel A and the other set to Panel B
> 
> This is not considered parallel because they don't begin and end together. Just make sure you size your conductors for the de-rating.


Can i bring one ground from the meter base to the first panel and bond to the second one? Also, the previous electricians have 3 empty containers( 3 gutted panel enclosures) in the utility room, 1 is bigger than the other 2, other 2 small ones are the 200A panels, and the first bigger one (where the 4" pvc enters) im assuming is going to be the main breakers for the 2 panels. So since technically they will begin and end together, is it now considered parallel? Im not sure why they set it up the way they did but now I have to work around it.


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## Dennis Alwon (May 9, 2009)

I really don't feel comfortable answering without pictures or something. Are you getting this inspected?


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## JAElectrician2290 (7 mo ago)

Dennis Alwon said:


> I really don't feel comfortable answering without pictures or something. Are you getting this inspected?


Yes permits pulled and will be getting inspected


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## JAElectrician2290 (7 mo ago)

JAElectrician2290 said:


> Yes permits pulled and will be getting inspected


I’m a licensed journeyman , I’ve done only 2 -400A services in the past and I’ve done them both the same . This is just a different set up for me ( the 4” pipe, 3 panels in the basement ) just trying to get an idea of what I need to do with what they left me . I can get some pictures tomorrow , just looking for some insight . I’m not a hack or doing this illegally , I’m literally trying to find out the best / right way to work with what they left me.


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## Southeast Power (Jan 18, 2009)

catsparky1 said:


> Why are you running 600 cu?


Don’t pull 600 copper, that’s a waste. Pull 5-300 kcmil aluminum


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## kb1jb1 (Nov 11, 2017)

JAElectrician2290 said:


> Can i bring one ground from the meter base to the first panel and bond to the second one? Also, the previous electricians have 3 empty containers( 3 gutted panel enclosures) in the utility room, 1 is bigger than the other 2, other 2 small ones are the 200A panels, and the first bigger one (where the 4" pvc enters) im assuming is going to be the main breakers for the 2 panels. So since technically they will begin and end together, is it now considered parallel? Im not sure why they set it up the way they did but now I have to work around it.


Without seeing what you are doing, I don't believe you need a ground wire between the meter and the panels. Is there a disconnect by the meter? Normally the grounded conductor is both neutral and grounding but only between the meter and service disconnect.


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## JAElectrician2290 (7 mo ago)

Southeast Power said:


> Don’t pull 600 copper, that’s a waste. Pull 5-300 kcmil aluminum


Wouldn’t I have to pull 5-350 kcmil because of deration? I could be wrong


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## JAElectrician2290 (7 mo ago)

kb1jb1 said:


> Without seeing what you are doing, I don't believe you need a ground wire between the meter and the panels. Is there a disconnect by the meter? Normally the grounded conductor is both neutral and grounding but only between the meter and service disconnect.


That’s the other situation , having trouble finding a 400 amp ( I guess it’s technically a 320?) meter base /disconnect in stock


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## kb1jb1 (Nov 11, 2017)

JAElectrician2290 said:


> That’s the other situation , having trouble finding a 400 amp ( I guess it’s technically a 320?) meter base /disconnect in stock


Check what the utility requires. Some will allow the 320 to be used on a 400 amp. Some require a 400 amp Trans S CT cabinet.


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## splatz (May 23, 2015)

Southeast Power said:


> Don’t pull 600 copper, that’s a waste. Pull 5-300 kcmil aluminum





JAElectrician2290 said:


> Wouldn’t I have to pull 5-350 kcmil because of deration? I could be wrong


With 4-6 current carrying conductors in a raceway, you have to derate 80%; so to wind up with 400, you have to start with 500. (Divide: 400 / 80% = 500) 

For two parallel conductors, that's 250 amps per wire, and you can use the 90* column. In the 90* column, 300kcmil is the smallest greater than 250 at 255.


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## yankeejoe1141 (Jul 26, 2013)

If you're on the 2020 cycle then table 310.12 says you only need 400 copper or 600 aluminum to feed a 400 amp service.

Couldn't you just pull 600 al from the meter to the main disconnect enclosure, and then feed each 200 amp panel with 4/0 al from there.


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## Dennis Alwon (May 9, 2009)

It sounds like you have a 4" conduit going into a large JB that, in turn, feeds 2 - 200 amp panels. You could run 600 kcm aluminum and splice at the junction box. Or you can run two sets of 350 kcm. Both originate at the meter and go into the junction box and then one set into each panel. No splices in the JB and you won't have to worry about getting the wires the same length because it is not a parallel run.


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## Tonedeaf (Nov 26, 2012)

JAElectrician2290 said:


> Hey guys I just joined as a new member and had a few questions about a 400Amp Underground service that I will be taking over for a different EC. They currently have 4" conduit ran from where the pedestal is going, inside the house to 2-200Amp panels. My question is, I am under the impression of running 600kcmil copper from meter base located at the pedestal to the main disconnect located inside the house ( they left 3 empty containers in the home, bigger one im assuming they planned on putting the main disconnect, main breakers inside a seperate enclosure an then feeding the 2-200 amp panels?) The last 400A service I did, I ran 2-parallel service conductors to the house, where I then entered into a trough and made my connections to my conductors feeding my 2-200Amp panels. This is just a different set up than how Ive done it in the past and would like some insight on what their plan was with this. Thank you and sorry in advance if my explanation doesnt make any sense, ill try to explain more briefly.



600 MCM copper your gonna need to take out a mortgage to buy that.

If there is no CT cabinet the actual rating of the service is most likely 320A. You can use 500 MCM aluminum to the service disconnect and call the service 350a if the inspector ask. The 4 utilities that I deal with in my service area are similar with respect to 400 amp residential. They have a 320A service with no metering that everyone calls a 400 amp service and a true 400 amp service with a metering cabinet.

All the 400amp meter bases that i know of with no metering are rated for 320amp.


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## Dennis Alwon (May 9, 2009)

Tonedeaf said:


> 600 MCM copper your gonna need to take out a mortgage to buy that.
> 
> If there is no CT cabinet the actual rating of the service is most likely 320A. You can use 500 MCM aluminum to the service disconnect and call the service 350a if the inspector ask. The 4 utilities that I deal with in my service area are similar with respect to 400 amp residential. They have a 320A service with no metering that everyone calls a 400 amp service and a true 400 amp service with a metering cabinet.
> 
> All the 400amp meter bases that i know of with no metering are rated for 320amp.



I disagree with you. A 400 amp meter base is rated 400 amp for non continuous loads. It is rated 320 for continuous loads which isn't an issue with dwellings. 

600 kcm aluminum is fine since he can take 400 amps x 83% and get 332 amps. The wire only needs to be sized to 332 amps. Each wire spliced at the jb only needs be sized for 200 amps.


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## Tonedeaf (Nov 26, 2012)

Dennis Alwon said:


> The wire only needs to be sized to 332 amps. Each wire spliced at the jb only needs be sized for 200 amps.



Look up wire size for service cable conductors for single family dwellings. NEC has a table.

it there is a disconnect to sub panels he needs to use 600 other wise 500 mcm is code


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## Dennis Alwon (May 9, 2009)

Tonedeaf said:


> Look up wire size for service cable conductors for single family dwellings. NEC has a table.
> 
> it there is a disconnect to sub panels he needs to use 600 other wise 500 mcm is code


If the wire is run to a junction box then that wire can use the 83% rule. The taps to the panels cannot.


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## Dennis Alwon (May 9, 2009)

Please go to diychatroom.com

This site is for professionals only I am closing the thread thank you


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