Planning wiring for my garage - have questions

[katit]

Can somebody do sanity check on my plan?

I have attached garage and I will be installing 100A subpanel. Wire will be run in a basement from main panel and then through the wall to garage.

1. I'm planning on using 3-3-3-2 NM wire with no conduit. Does it sound right? Length of run will be about 50-60 feet, main panel in opposite corner

2. With preparation for welder I will install 240v 50A outlet using 8 gauge wire.

3. Other stuff all will be on 12 gauge wire. Outlets, lights, etc.

[Norcal]

Originally Posted by katit

Can somebody do sanity check on my plan?

I have attached garage and I will be installing 100A subpanel. Wire will be run in a basement from main panel and then through the wall to garage.

1. I'm planning on using 3-3-3-2 NM wire with no conduit. Does it sound right? Length of run will be about 50-60 feet, main panel in opposite corner

2. With preparation for welder I will install 240v 50A outlet using 8 gauge wire.

3. Other stuff all will be on 12 gauge wire. Outlets, lights, etc.

For #1 if this is NM cable #3 copper is only rated for 85A for 100A #2 AWG is rated for 95A & if the load does not exceed 95 A it is allowed to go to the next higher standard rated circuit breaker. (Standard in this group is 70,80,90,100,110,125 amperes).

For #3 is this NM cable (Romex®)? If this is the case 8 AWG is 40 amperes max, if in conduit w/ the more common THHN/THWN insulation then your OK.

NM cable per NEC article 334.80 is sized in the 60º column, SE type cables in areas that have adopted the 2008 NEC is also sized in the 60º column, if using the 2005 or earlier then the 75º column is OK to use to size them.

[katit]

#1 - Yes, copper. Our county won't let me touch aluminum. Nor I really want to. Thinner wire, negligible savings over AL.

#2 - Yes, I meant THHN - common one that's sells. Didn't know there is important differences

Our county uses NEC 2005.

Looks like i'm on a good track. Will see what inspector says about my plan.

One more Q. With feeder wire when I move it out from basement - there will be bend and tight space coming into the wall that's shared between garage and basement. Should I put metal elbow or something like that to protect wire?

[katit]

Originally Posted by Norcal

For #1 if this is NM cable #3 copper is only rated for 85A for 100A #2 AWG is rated for 95A & if the load does not exceed 95 A it is allowed to go to the next higher standard rated circuit breaker. (Standard in this group is 70,80,90,100,110,125 amperes).

So, which "standard" cable would I use? 2-2-2-3?

[Norcal]

Originally Posted by katit

So, which "standard" cable would I use? 2-2-2-3?

#2 AWG is fine for 100A as long as your load does not exceed 95A, if your area is on the 2005 NEC & the cable is not a type NM but is a SER type, then your original plan is good to go. Read the cable jacket to see what type it is.

[katit]

I don't have a cable, I'm going to get it. Should I ask for SER 2-2-2-3 then?

[noslo04]

Currently doing similar project myself. My thoughts are:

1. Inspector said, if using aluminum SER, go with #1 (1-1-1-3) for 100A subpanel.
2. 8/2 is acceptable for 50A welder-only circuit, depending on welder duty cycle. Mine would be light duty residential, so 8/2 it will be.
3. Convenience outlets on 12/2 20A; T8 lighting and garage door opener circuits will be 14/2 15A.

No worries using aluminum when connections are properly torqued and no-ox paste is used. Aluminum is more flexible than copper and there will be 11 bends in my 44' run. Again, just my thoughts.

[Norcal]

Originally Posted by noslo04

Currently doing similar project myself. My thoughts are:

1. Inspector said, if using aluminum SER, go with #1 (1-1-1-3) for 100A subpanel.
2. 8/2 is acceptable for 50A welder-only circuit, depending on welder duty cycle. Mine would be light duty residential, so 8/2 it will be.
3. Convenience outlets on 12/2 20A; T8 lighting and garage door opener circuits will be 14/2 15A.

No worries using aluminum when connections are properly torqued and no-ox paste is used. Aluminum is more flexible than copper and there will be 11 bends in my 44' run. Again, just my thoughts.

If NM cable, your ampacity is still limited to 40A for 8 AWG because of the NEC limiting NM to the 60º C column ampacity.

[katit]

What about 6/2. Is it good enough for welder? I don't care about wire cost right now, just want to make sure I can get any kind of welder and be able to use it..

[Norcal]

Originally Posted by katit

What about 6/2. Is it good enough for welder? I don't care about wire cost right now, just want to make sure I can get any kind of welder and be able to use it..

6/2 is fine for 50A....

[katit]

Originally Posted by Norcal

6/2 is fine for 50A....

What about grounding? There is 2 hot wires for 240, 1 common and 1 ground, no? Shouldn't it be 6/3?

[Norcal]

Originally Posted by katit

What about grounding? There is 2 hot wires for 240, 1 common and 1 ground, no? Shouldn't it be 6/3?

US 240V has two hots & a grounding conductor, welders usually do not require a neutral.

[katit]

Seems like I need to do Aluminum SER. Difference in price huge. I have 110ft run and al is at $2/ft vs $6/ft for copper.

[DURAMAT]

6 gauge for the welding recep. and Id make sure you pull a nuetral out too. 2 hots, neutral, and ground.

[DURAMAT]

and you may have to upsize your alum wire for the amperage too. Copper will hold more amps than aluminum

[katit]

Originally Posted by DURAMAT

6 gauge for the welding recep. and Id make sure you pull a nuetral out too. 2 hots, neutral, and ground.

Yep. Thats what inspector told me today.

[katit]

Originally Posted by noslo04

No worries using aluminum when connections are properly torqued and no-ox paste is used. Aluminum is more flexible than copper and there will be 11 bends in my 44' run. Again, just my thoughts.

Where I can get more info on properly connecting aluminum wire? It seems like the way I have to go

I also planned to run 12/3 along wall for split recepticles, but seems like it won't work with GFCI

[mikeyr]

why run a neutral for a welder ? I can see it for a something like a dryer but not a welder ?

It does not matter as the original poster said the inspector told him to so he has to, but I was wondering why ? I did not run 6-3 for my welders, I did for the dryer and oven in the kitchen but in the garage its straight 6-2.

[Aceman]

Originally Posted by katit

#1 - Yes, copper. Our county won't let me touch aluminum. Nor I really want to. Thinner wire, negligible savings over AL.

Originally Posted by katit

Seems like I need to do Aluminum SER. Difference in price huge. I have 110ft run and al is at $2/ft vs $6/ft for copper.

Huh? So are you allowed to use aluminum or aren't ya?

Originally Posted by DURAMAT

and Id make sure you pull a nuetral out too.

Why? Are they making welders now that require a neutral?

[katit]

Aceman, my friend told me about aluminum. Today inspector didn't say anything - I will double-check tomorrow. I hope aluminum allowed.

For 6-3 welder it's what I was told. I will double-check tomorrow.