10/3 for two120v circuits

[tallfreak]

I am wiring my 40x60 shop, and I want to run four 20amp 120v circuits. The outlets will be in duplex boxes each box containing two circuits with 10 awg. Probably overkill I know. The run of outlets will be about 80ft long.

The problem is I have to go up and over my roll up door to get to the first box on the run. Probably 40ft by the time I make it to the first box. Can I use 10/3 on a 20 amp bonded breaker to run two circuits? Black hot and red hot and share the common. I think I should be ok as long as the black and red are out of phase, but I wanted to make sure.

I really dont want to have to run four circuits of 10/2.

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[sberry]

You can do this but unless there was a specific reason I might go 12 at that distance. Up to and over 100 ft I might think about a bigger wire if,, there were specific heavy loads.

 

[sberry]

Are these general use? If they are 2 circuits is likely suffecient and still may be half used. Just cause there is a 20A breaker doesn't mean that there will be 20 applied load or size and type is irrelevent. If there are multiple loads having 2 circuits may make it easier than 4 and sharing loads with them,, have multi wire but 1 load on each one is using 120 on each instead of 240 on one which is kind of the point.

 

[Dagny]

I agree with berry on wire size. do you need gfci protection?

 

[tallfreak]

I will have a 2hp drill press and a 2hp belt grinder. They shouldn't ever be run at the same time, but I want to be able to add more heavy consumers if needed without pulling more wire. Plus I have a battery charger that is capable of of about 18 amps that will be running often.

Since the run of outlets is 80ft long and about 40 ft from the panel the entire circuit will be about 120ft long. Would it help to run 10 awg to the first box and then 12 after that?



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[sberry]

If I thought this load was gonna happen at that distance might run a 2 cable to 6 or 8 spaces. Makes the branches short copper common 12.

 

[AntonLargiader]

..Plus I have a battery charger that is capable of of about 18 amps that will be running often.

Is that 18A to the battery (believable) or 18A draw on the 120V circuit (less so)?

 

[sberry]

My building is 80x80. I have 100 ft to.start. use 2 alum to another panel and the other runs are short and it makes for a good welder circuit. Another handful of breaders and it makes most of it dedicated and separate for lights. There is a small water heater, I could get by with 1/2 what I got but it's simple and makes for short branches.

 

[tallfreak]

If I thought this load was gonna happen at that distance might run a 2 cable to 6 or 8 spaces. Makes the branches short copper common 12.

Are you saying 2awg?

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[tallfreak]

Is that 18A to the battery (believable) or 18A draw on the 120V circuit (less so)?

18a draw on the 120v circuit. Its capable of 80a on a 12v battery. It's for maintaining 14.4v on a car while programming.

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[Norcal]

I agree with berry on wire size. do you need gfci protection?

Any shop needs it.

 

[AntonLargiader]

Anything that critical that draws that much should be on its own breaker IMO. You don't want to lose that charger when something else kicks on.

18a draw on the 120v circuit. Its capable of 80a on a 12v battery. It's for maintaining 14.4v on a car while programming.

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