220v Question.

[Adam@theHoffmanGroup]

Here is my problem. I am mid way through the update of my small one car garage. I have already added 12 110v outlets and I have a 90A sub panel out there. I am wiring one 20a 220v line for my compressor and would like to wire a second so I can add a plasma or a new welder. So what should I wire to the extra? Should I run 10/3 to it? It will have to be a 30a. I am not sure if I will need to have 3 conductors or if 2 will work. or if there is an issue with wiring it for 3 and using 2.

I tried searching... But was unsuccessful.

Thanks

Adam

 

[walrus]

So what should I wire to the extra?

It depends on the load? Its hard to guess what you'll need in the future. If you have some idea what you might buy in the future, look up the specs for the electrical and size accordingly

 

[Adam@theHoffmanGroup]

That makes sense. I may upgrade it to a 50a line. Should I run 3 conductor or two?

 

[Dan0myte]

Run 8/2 to the outlet. That way you can run up to 50A if need be, or as little as you want as well. Nothing wrong with running 20A or 30A of current through an 8/2 line, but if you run too small of a line then you're in trouble if you get a device with too much draw.

There's no need for 3 conductor unless you're installing a dryer or a stove.

 

[Adam@theHoffmanGroup]

awesome thanks for the answer.

 

[Torque1st]

There's no need for 3 conductor unless you're installing a dryer or a stove.

8-3 with Ground would be good for many possible things that might need a neutral in the future.

8-2 with Ground would not have a neutral if you needed it at some time in the future.

As long as you are wiring for an unknown possibility or device you might as well run the extra conductor.

 

[Norcal]

Run 8/2 to the outlet. That way you can run up to 50A if need be, or as little as you want as well. Nothing wrong with running 20A or 30A of current through an 8/2 line, but if you run too small of a line then you're in trouble if you get a device with too much draw.

There's no need for 3 conductor unless you're installing a dryer or a stove.

8/2 is only good for 40A, the NEC requires NM be sized at the 60 degree ampacity, + oversizing wiring w/ NM type cable causes other code issues that makes it a non-compliant install.

250.122(B)

(B) Increased in Size. Where ungrounded conductors are
increased in size, equipment grounding conductors, where
installed, shall be increased in size proportionately according
to the circular mil area of the ungrounded conductors.

The equipment grounding conductor becomes too small in a NM cable when oversizing over 10 AWG NM cables because w/ 6 & 8 AWG NM the grounding conductor is only 10 AWG.
The code section was a copy & paste from the 2008 NEC & is unchanged from the 2005 edition.