Sub panel wiring question

[DTE]

I have done a lot of reading of past posts concerning wire size going from the house panel to a new panel in the garage. These are the things I know at this point, it is a 130 ft run, I am going to set a 100 amp panel , I will use aluminum wire and it will be ran in 2in conduit. I will start out with very little load as my build is a slow work in progress. But it will end with the normal stuff, lights, welder, Air compressor and a Heat pump. So I call a local supply house and ask about MHF wire in the #2 size and all they stock is 2-2-4-6- which has a reduced ground and neutral. From what I have read on here if you use a 2-2-2-2 MHF it is good for 90 amps. If I was to run 4 individual AL wires to carry 100 amps what size would they need to be ? Or could you step it up and run #4 size AL. or is there a size in between. Or does using individual wires give you the
in-between size ?

 

[pattenp]

For full 100A use 3 #1 Al and a #6 Al for the ground. The next size up of MHF is 2/0-2/0-2/0-1.

 

[Aceman]

I have done a lot of reading of past posts concerning wire size going from the house panel to a new panel in the garage. These are the things I know at this point, it is a 130 ft run, I am going to set a 100 amp panel , I will use aluminum wire and it will be ran in 2in conduit. I will start out with very little load as my build is a slow work in progress. But it will end with the normal stuff, lights, welder, Air compressor and a Heat pump. So I call a local supply house and ask about MHF wire in the #2 size and all they stock is 2-2-4-6- which has a reduced ground and neutral. From what I have read on here if you use a 2-2-2-2 MHF it is good for 90 amps. If I was to run 4 individual AL wires to carry 100 amps what size would they need to be ? Or could you step it up and run #4 size AL. or is there a size in between. Or does using individual wires give you the
in-between size ?

#2 AL MHF is good for 90 amps, the reduced neutral/ground have no bearing on that ampacity. Since you have some 240v load in your garage, you do not need a fullsize neutral. Secondly, the ground is usually only fullsize(same size) in circuits 30 amps and smaller. Circuits larger than that, it's usually smaller than the "hots" and "neutrals".

2-2-4-6 would most likely work just fine in your situation provided your calculated load is under 90 amps.

 

[DTE]

For full 100A use 3 #1 Al and a #6 Al for the ground. The next size up of MHF is 2/0-2/0-2/0-1.

pattenp,
If I am understanding this wire sizing right MHF 2/0-2/0-2/0-1 is larger than 2-2-2-2 .Which is HOT-HOT-NEUTRAL-GROUND. So when you look at the numbers and you add the slash and the zero that increases the gauge of the wire, is that correct ? When you suggest using # 1 AL ( just wanna make sure I get it right) you mean #1 not #1/0 looking at wire sizing charts I see there are both. I will have to see what is available locally, I pulled the permit so I will have to check with the inspector to see what they want. As I stated earlier I do not know how much power I will need but I do not see any reason to leave anything on the table and at some point having to turn something off to turn something else on if that can be avoided rather easily. I will have to see if someone locale has the #1 wire and I will go with that.

 

[rburke65]

Yes, a #2 is smaller than a 2/0 or 00 or 2 ought. I'm sure the is a wire size chart on the Internet. Size go from small to large.....22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 1, 0, 00, 000, 0000. Then MCM but that's real big.

 

[wyliesdiesels]

OP- here ya go

http://www.engineeringtoolbox.com/awg-wire-gauge-circular-mils-d_819.html

 

[pattenp]

So you'll know a 100A breaker usually takes up to a #2/0 wire so there is no issue with fitting a #1, or #1/0 or 2/0 in the breaker if you go with the 100A feeding breaker.

 

[DTE]

So you'll know a 100A breaker usually takes up to a #2/0 wire so there is no issue with fitting a #1, or #1/0 or 2/0 in the breaker if you go with the 100A feeding breaker.

I am going to use the #1 AL with the #6 ground and there will be a 100 amp breaker in the panel on my house and the panel I put in the garage will have a 100 amp main. I found the wire locale for $190.00 for the 4 130 ft pieces. What markings should the wire have if it is going in conduit ?

 

[wyliesdiesels]

Honestly theres many types of insulation.

As long as its not URD youre good!

 

[pattenp]

You are looking for wire marked XHHW-2 or RHH/RHW-2 or THHN/THWN-2. You do not want wire that has only a USE-2 marking because it's for outside only, it can't go into the house. If the wire has the USE-2 marking along with some of the others then it can be installed inside. USE-2 allows it to be direct buried but it can be placed in conduit.

 

[DTE]

Thanks pattenp and wyliesdiesels for the info. I found a locale supply house that can get what I need. I have no interest in doing any wiring( from a safety standpoint ) but I have a basic understanding of it and I like to know what I need so when buying something I get the right item and from all the posts you have made it has helped a lot.

 

[DTE]

I am just putting this out there to share what I encountered with my build, I was all set to use #1 al wire to run to my sub panel, but seeing I am not a electrician or contractor for that matter I go by and see an inspector before I do much so I don' have to do it over. Long story short I am glad that I did. They wanted 1/0 al wire to cover the 130 ft run using a 100 amp breaker. I appreciate all the advice and I now know a lot more about wiring than I did and right or wrong at the end of the day the inspector has the final say. It is like the whole build, I need 1/0 instead of #1 oh it just costs more ! but the good news is I was in Lowes and they had a eaton 100 amp value pack with the main and five 20 amp SWD rated breakers and 1 30 amp that I got for 32.00.

 

[Aceman]

I am just putting this out there to share what I encountered with my build, I was all set to use #1 al wire to run to my sub panel, but seeing I am not a electrician or contractor for that matter I go by and see an inspector before I do much so I don' have to do it over. Long story short I am glad that I did. They wanted 1/0 al wire to cover the 130 ft run using a 100 amp breaker. I appreciate all the advice and I now know a lot more about wiring than I did and right or wrong at the end of the day the inspector has the final say. It is like the whole build, I need 1/0 instead of #1 oh it just costs more ! but the good news is I was in Lowes and they had a eaton 100 amp value pack with the main and five 20 amp SWD rated breakers and 1 30 amp that I got for 32.00.

I'll put this out there as well then. The NEC does not require you upsize wire for voltage drop, it is only a recommendation.

Of course there are always local codes that may apply, but to the NEC upsizing is simply a design issue, not a safety issue.

 

[wyliesdiesels]

1/0 is a bit overkill for that distance!