What size wire needed to feed 100amp sub-panel

[JWithers2005]

Im having the power company upgrade my service to a 320amp main panel so I will be able to pull 100amps from it to power all the goodies in my new garage. My question is, What size wire will be required to handle the 100amp feed to the garage sub-panel? Copper or aluminum? Im just trying to get an idea what it will cost to run the 75' or so of wire to power the new garage. Hopefully I will be able to use aluminum from the main panel to the sub. I know it's going to be costly if it requires a copper wire so hopefully aluminum is an option..Thanks for any help..

-Joey

 

[cj7365]

Not sure of the wire size, but my electric guy ran aluminum for my 100 amp panel that was about 125ft away

 

[JWithers2005]

Not sure of the wire size, but my electric guy ran aluminum for my 100 amp panel that was about 125ft away

That's good to know. I can only imagine what it would cost in copper. Do you remember what it cost you for the wire?

 

[pattenp]

For 100A you need at a minimum #1 AL or #3 CU. Aluminum is a third or less than the cost of copper. Go with AL. Note: This is based on 75C temp rating, if 60C is used then the next size larger wire is needed.

 

[JWithers2005]

For 100A you need at a minimum #1 AL or #3 CU. Aluminum is a third or less than the cost of copper. Go with AL. Note: This is based on 75C temp rating, if 60C is used then the next size larger wire is needed.

Ok thanks for ur reply..do u know of a website that has what you are talking about? so I can check pricing? a link would be great if it isn't too much trouble. thanks again

 

[Falcon67]

For those sizes, you'll probably want to call a local electrical supply. You don't usually or always find those in home stores. Especially #3 CU. Now if you scale back to 75A or 90A (ask your local inspector what's allowed), you could use 2-2-2-4 aluminum mobile home feeder, which runs about $1.6x a foot more or less.

 

[pattenp]

I never have found trying to price wire on the web a worth while effort. I just go to my local Lowes or Home Depot. For the larger wire such as the mobile home feeder I go to my local electrical supply. The last 2-2-2-4 AL MHF I purchased was around $1.20US per foot.

Ok thanks for ur reply..do u know of a website that has what you are talking about? so I can check pricing? a link would be great if it isn't too much trouble. thanks again

 

[Aceman]

Im having the power company upgrade my service to a 320amp main panel so I will be able to pull 100amps from it to power all the goodies in my new garage.

Is this a meter base or panel or a combo of both. That'll dictate how many wires to run to the garage....

A "320" is slang for a 400 amp meterbase is why I ask.

 

[JWithers2005]

Is this a meter base or panel or a combo of both. That'll dictate how many wires to run to the garage....

A "320" is slang for a 400 amp meterbase is why I ask.

just a meter socket and a service panel from what i understand..im green when it comes to electrical so I can't exactly talk intelligently about the subject..i spoke with the electrician today and he suggests a 200amp panel and a 70 or 90amp breaker to power the panel in the garage. he wants a thousands bucks just to upgrade the panel on the house!! I was blown away by that price but maybe that is the going rate??

 

[pattenp]

$1000 sounds good to me. Parts aren't the expense, it's the labor/time.

 

[rktompsett]

I'm using 100 amp rated alum 2-2-2-4, it has 3 black #2 gauge, 1 #4 gauge with a yellow stripe. I'm using the #4 as my ground. Mark one of the #2 with white tape to be neutral, the other #2's are the hots. I did a continuity check at the other end to find the neutral with a DVM.

 

[Bigblockyeti]

I'll eventually run direct burial aluminum wire 160' from my panel to sub-panel in my shed and it is far cheaper than copper based on what I've seen.

 

[pattenp]

I'm using 100 amp rated alum 2-2-2-4, it has 3 black #2 gauge, 1 #4 gauge with a yellow stripe. I'm using the #4 as my ground. Mark one of the #2 with white tape to be neutral, the other #2's are the hots. I did a continuity check at the other end to find the neutral with a DVM.

#2 Al as a branch feeder is only to be used at a max of 90A. Also the wire you described is URD and is only allowed to be used outside because of most likely having only a USE rating.

 

[Jakemedic]

I did 3-#3 copper and a #6 ground for my woodworking shop with 100 amp breaker. I got 75’ and used about 70’. Cost 300.00 in April online delivered. Much cheaper than big box stores and I had it in 4 days.

 

[Norcal]

This is a 8 year old thread.

 

[NUTTSGT]

This is a 8 year old thread.

Yes, keep in mind that rktompsett has brought it back from the dead. This is the second thread he has done it with.



Because codes change and older information may no longer be pertinent, this thread closed.