Question regarding 400 Amp service

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Old 05-07-07, 06:26 AM
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Question regarding 400 Amp service

I'm in the process of upgrading my detached garage/workshop and apartment to a 400 amp service. It was a 200 amp for the apartment, and no power in the garage workshop. That was an illegal feed, and was removed before I got the house. The electrician doing the work is a my friends brother, so I'm getting a decent break in the price, but I have to buy all the parts on my own with the list he provided me. The meter box I picked up is a Square D, 2 gang, 400 amp meter box with Main breakers and service bypass. It was quite expensive, and quite large. Wasn't expecting that. It has holes in the top and bottom for the 4" pipe, but the lugs are on the bottom below the meters. My electrician is telling me that this box is made for a bottom feed, so he'll need to route the wires up from bottom. I don't see why you can't feed the wires in from the top and down the box behind the back of the meters. Otherwise, why would there be 2 big plates on the top of the box, and a plastic looking shield behind the meters with about 3 inches of space. He told me he won't do it regardless, cause he feels it's not safe. I'm guessing cause maybe the 500 MCM wire is too thick to route back there, or maybe a code issue? Don't know as I'm not an electrician, but it looks like there is plenty of room. Isn't 500 MCM wire only like an inch think? I haven't picked it up yet, but he makes it sound like it's as thick as my arm. Any of you pros out there have any opinions on this? Have you ever run into a situation like this. I guess what he's planning on doing is using an LB connector on the side of the box, and connecting the 4inch pvc there. Just trying to get a feel for it. I don't want to argue with him too much, cause of what he's charging me for the job. It's not only a 400 amp service upgrade, but also installing the 2nd load center for the garage/workshop, and moving the apartment panel upstairs into the apartment. I just want to know for my own knowledge. thanx.
 

Last edited by ampm24; 05-07-07 at 06:26 AM. Reason: spelling.
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Old 05-07-07, 08:41 AM
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Most of the panels I use are for top or bottom feed. He's being unprofessional if your panel is designed for it and he won't do it. Sometimes, you can also move the lugs inside to make it easier for the top feed.
 
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Old 05-07-07, 06:12 PM
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can you toss the part number of the meter/service panel so I can look it up.

Some of these are setup to take only top or bottom feed.

btw; yes, 500 mcm is about an inch thick. When is the last time you tried to bend 3 1 inch thick rods of copper and place them into the area you are looking at? It can be a real pain sometimes depending on how the cabinet is set up.

and you think that part was expensive, just wait until you buy the copper!!!!!!!!!!!

I don;t know what it is currently but I have seen it over $12/foot in the recent past.

edit: I was just at the square D site and the only units that are within your given specs are underground feed only. with the number I can tell you for sure.
 
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Old 05-08-07, 11:49 AM
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I'll grab the part number when I get back home. My electrician is going to bring the wire into the side of the panel using an LB. I can see the issue with bending this wire, It's not very flexible. I was able to get away with 500mcm aluminum which was a lot cheaper then copper. The copper was 11.74 per foot, the aluminum was only 2.75. We're not using a full 400 amps, technically only 300, so the power company and inspector were fine with the aluminum. The SER quad 200 amp service cable wasn't cheap either. 4/0,4/0,4/0,4 aluminum was 5.32 a foot. I needed almost 100 feet of that and 3 30 foot sections of the 500mcm. The damn wire was the most expensive part of the project.
 
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Old 05-08-07, 12:59 PM
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a resi service is allowed to use 600 mcm al or 400 mcm cu for a 400 amp service. 350 amp service is 500 al and 350 cu, 300 amp is 350 al or 250 cu.

This is based on the breaker size of the service.

4/0 al cable is only good for service entrance for a 200 amp service. If the POCO is installing the service drop or lateral, they kind of get to follow their own rules for what they install.

my company is currently bidding a job for (I think) about a 900 foot run feeder to another building (all underground). The copper cost is $20k while aluminum is $8k. I think you are going to be seeing a lot of aluminum used in place of copper.

Now mind you, I have no problems with al where it is allowed. I have even used it for feeders to a subpanel without a worry. As long as the terminations are rated to accept aluminum, I have had no problems with it.
 
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Old 05-11-07, 07:37 AM
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I never did remember to get the part number, but I did confirm with the distributer that it is indeed a bottom feed unit. I guess most of these are. I guess the holes on the top are for the load center feeds. The price of this whole job is crazy. I'm over budget by about 600 bills. Come on, 157 bucks for a PVC weather head and 60 bucks for an LB. The cost of this 4" stuff is nuts. Oh well. too late now. At least I have lots of power. Even the cost of copper romex is nuts these days. I shouldn't have gave all that CAT6 scrap I had from my last project away. I did about 50000' of voice and data cable in a 186000 sqft manufacturing facility, and gave all my scraps to the alarm guy cause I didn't think it was worth it. I think he got close to 400 bucks for it all. Oh well.
 
 

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