# Running 230 out to the shop



## agallant (Jul 1, 2010)

I currently have 8/2 wire running out to the shop. I just bought a 230V saw so I will need to run 8/3 out to the shop. My question is how many amps can I put on each leg of the wire running out to the shop

8/3 wire at a 120 Foot run how many amps can I put over each leg? It is running from the pannel under my electrical meeter where the power comes in from the street.

-AG


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## TopamaxSurvivor (May 2, 2008)

#8 is good for 40 amps.


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## mechanicalengineer (Sep 27, 2010)

You actually need to have a 4 wire run. For a 240/120 volt service you need 2 conductors for 240 V, a neutral and a ground.


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## mathom7 (Jun 6, 2010)

8/3 does have 4 wires, the ground is implied

Don't think of it as amps on each leg. You put a double pole breaker in your main box and it feeds each load wire, the came amperage in each one.

I would suggest at least 6/3 to give you 60 amps.

Not sure what exactly your planning, but, I believe the 240 volt has to be a dedicated circuit by code. Hopefully a professional will post to clarify. You can't take 240v out there and steal a branch for a 120v line.

I would guess most of us run sub panels in our shops.


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## TopamaxSurvivor (May 2, 2008)

Yes, no stealing a leg for 120 ) You need to have a disconnect at the separate building with a subpanel to break it into smaller circuits and it needs to be grounded just as a new service in addition to the "implied" equipment ground in the feeder cable.


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## agallant (Jul 1, 2010)

From the main panel I was going to run 8/3 to the shed with one breaker on the black wire and one on the red. There is that little clip that bonds tow breakers togeather on 220 so I was going to put that on. From there it will run to a panel in the shop. The panel I have out there takes two feeds but all of the breakers are in a row and alternate the feed. So

Breaker 1 Feed 1
Breaker 2 Feed 2
Breaker 3 feed 1
breaker 4 feed 2 
on and on

This was if I want 220 I use breakers 1 and 2 which are comming from different feeds.

Sound right?


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## mathom7 (Jun 6, 2010)

By code a detached structure can have 1 circuit without a sub-panel, more then 1 circuit and you need a panel that is grounded, to the ground, not grounded through the feeder line.

If it's an attached shop, you can just run a circuit from your main panel if you want.

I hated my circuits class in college, who knew my woodworking hobby would force me back


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## TopamaxSurvivor (May 2, 2008)

agallant You Got it 

mathom7, I dropped out of college on advice of a EE with Phd. There circuits classes are better placed in an apprenticeship


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## mathom7 (Jun 6, 2010)

So you currently have a 240 panel in your shop, only you don't have a neutral from your main?

You should have a double pole breaker in the main feeding the 2 load wires, I don't think you can use 2 single poles in tandem, it has to be a double. Then another double in the sub-panel to the equipment.

I don't know about the code issues, but, if you are only running a table saw or jointer on the new circuit you can probably get by without the neutral, this is needed for some equipment that needs both 240 and 120. For example the light on a 240V band saw.


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## agallant (Jul 1, 2010)

from main
black to breaker 1
red to breaker 2
white to nuteral bus
exposed copper to ground bus

on sub
black to feed 1
red to feed 2
white to netural bus
exposed copper to ground bus

right?


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## TopamaxSurvivor (May 2, 2008)

" 2 single poles in tandem" depends on the UL listinig. Lots of 2 p0le breakers are nothing but 2 singles premanently in one assembly with the handles tied together. You need the neutral to have 120. It won't work just runnin it to a ground rod.


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## TopamaxSurvivor (May 2, 2008)

Yup


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## mathom7 (Jun 6, 2010)

Sounds good.

I think it was just a phrasing issue. As long as what you are calling breaker 1 and breaker 2 are permanently tied together, so if one trips they both trip your fine. What you can't have is one of the poles to trip, and the other to remain open, this is potentially dangerous.


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## canadianchips (Mar 12, 2010)

Always check with your local electrician. Electricity is deadly !
This sketch may help.


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## Knothead62 (Apr 17, 2010)

To all: by running 120 feet, will there be any voltage drop or is this covered with the 6/3 wire? Personal question here.


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## canadianchips (Mar 12, 2010)

The National code allows 5% drop from source to last outlet. I used 120 feet x 40 amp load and # 8 awg wiring, came up with a 3% drop. Then I calculated same 120ft x 40 amp x #6 wire and had a 1.7% drop.


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## TopamaxSurvivor (May 2, 2008)

Depends on the size of the load. If you are going to start a 3 hp saw, you will probably see the lights flicker when it starts. You may be able to get your wire a lot cheaper by going to single strand and putting it in pvc conduit under ground.


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## Knothead62 (Apr 17, 2010)

Thanks, canadianchips!


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