2 Sub Panels , 1 attached garage 1 next to main panel?

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Old 04-06-15, 03:30 PM
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Wink 2 Sub Panels , 1 attached garage 1 next to main panel?

I currently have a 200 main amp panel in my basement. It is pretty full and I would like to add a second subpanel for when I finish the basement and a third subpanel for the garage. I looked at this forum a good amount and this is my current plan. I live in the US. Please tell me if I am way off base. I would like to run the maximum amps I can to the 3 car attached garage using 2-2-2 3E Aluminum SEU wire as it seems to be the most cost effective. The run will be about 70' and will all be inside. Would I be able to run an 80 amp breaker or 100 amps? I am getting a little confused on the temp ratings. What panel would you all recommend, I was looking at a 12 space 24 circuit main panel for the garage and basement. Once I have the garage wired I would also like to have at least a 60 amp panel in the basement for a future home theater and other things. Are there any special precautions I need to take with aluminum wire, is there a specific panel I should use? I have done a fair amount of circuit work before but never ran a sub panel or two for that matter. Any and all help would be much appreciated. Thanks
 
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Old 04-06-15, 04:07 PM
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The first thing you need to do is run a demand load calculation (do a search using that term) to see if your incoming 200 amperes is enough for your proposed load. If it is then you may proceed with your plan.

The aluminum conductors need to be properly terminated, I'll let the practicing electricians cover that issue. The #2 conductors may have at most an 80 ampere circuit breaker feeding them.

Are you planning on having a shop in the garage or an electric car charger? If no to both then 80 amperes at 240/120 volts is way overkill in the garage. The proposed 60 amperes to the basement may also be way more than needed.
 
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Old 04-06-15, 04:54 PM
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The feeders to the panels will need to be 4 wire.
 
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Old 04-07-15, 07:23 AM
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I will run a demand load later today when I get a chance. There are really not a lot of high current things in the main panel atm so I was a little shocked to see how full it is but I guess more circuits is better than less.

I plan on running a compressor and maybe a welder. I will have other tools running eventually like a dust collector and maybe a table saw. I am sure the 80 amps is overkill but I figured better to be safe than sorry and wish I had more juice out there.

Would it be better to run 60 amps and a copper line? I just moved into this new place and plan on living here a long long time and I like crazy projects so who knows what I will be doing in 5 years. I will definitely check out the basement sub panel before I do that as I am sure 60 amps is overkill. I have never worked with aluminum wire before so doing it correctly the first time is my main concern.

The wire I have listed is 4 wire 2-2-2-3.

Thanks
 
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Old 04-07-15, 08:51 AM
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Would it be better to run 60 amps and a copper line?
That's what I would do. I can't imagine you needing more power than 60 amps unless you are planning on electric heat. Is the garage attached or detached?
 
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Old 04-07-15, 10:27 AM
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It is attached and I will be adding a heater but it will be natural gas. What size copper would I need to run? I can get the aluminum 2-2-2-4 for 1.69 a foot would the copper be cheaper? Seems like the aluminum is much more cost effective. Any reason to stay away from it?
 
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Old 04-07-15, 11:00 AM
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After doing some more research I see you have to use breakers certified for aluminum. Looks like most of them are now a days. The stores near me do carry 80 amp and 60 amp aluminum certified breakers.
 
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Old 04-07-15, 12:40 PM
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I did the load calculator and it said I was at 86 amps, if that helps.
 
 

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