How to power a new shop

[Aleks Hunter]

I don't think I 'd want to be you if someone from the fire department asked you what was up with the romex extension cord you describe. Romex is single conductor and not really intended to be wound and unwound and moved around as much as cord is. Nor is its sheathing as durable. First you absolutely need to put in a good ground with a copper rod at the outbuilding end. Rather than save a few pennies and use those pennies to buy a LOT of trouble, Invest a few dollars in direct burial or underground feeder cable dig a trench. Direct burial cable is not really much more expensive and is MUCH tougher. Check your local codes to see if you need to use conduit. If the wire is going across an area that is driven over, I'd invest in enough 3/4" black plastic pipe to reach and feed the UF cable through it then bury it.

To correctly size the wire, use a sizing tool like this one: http://www.powerstream.com/Wire_Size.htm Remember that you are sizing the wire for the whole length of the wire not just the line of sight distance.

[Tom Fischer]

Around here, conduit is required for burial. I had romex (gray) buried about 5 years ago. They fished it through black plastic well conduit (about 1" diameter), put a few inches of stone dust in the bottom of the trench, put the conduit in, and yellow "caution" plastic tape on top, before back filling.

[Matt Benton]

Aleks,

I never intended to build an extension cord from Romex. There are many sources for flexible 6/3 and 8/3 power cords that would be more managable.

Thanks to all who have replied. I intend to bury the romex in conduit as required by code.

Lastly, in order to get the line from the breaker inside the garage to the other side of the garage and down to the trench, can I run it through metal conduit on the outside of the garage under the eaves and down to the trench? I don't have access to the garage attic, and don't want to tear up the sheetrock to run through the walls...

Thanks!

[Anthony Whitesell]

Where is the panel located?

I would assume that running the line all the way to the eves and back down is going to be a long long way. I would get outside ASAP attach the PVC conduit just below the siding attached the foundation (if allowed by code). In would also install a pipe seal to plug the conduit after the wires are pulled and inspected. That will keep anything from coming back into the panel.

[Ron Natalie]

You can't bury romex in conduit. Underground conduit is a wet location. NM cable (aka ROMEX) is NOT approved for wet locations. You want to be running THWN or something approved for that in the conduit or UF or USE cable underground direct buried. How deep you have to go depends on what conduit you are using (or if you're just db'ing cable).


Yes, you can go out the back of the panel most likely to a LB fitting and down to (and below) the grade. If you're going to use PVC here where there's the possibility of physical damage you'll need sched 80 (or you can use metal).

[Jim Neeley]

Aleks,

I never intended to build an extension cord from Romex. There are many sources for flexible 6/3 and 8/3 power cords that would be more managable.
''
Thanks to all who have replied. I intend to bury the romex in conduit as required by code.

Lastly, in order to get the line from the breaker inside the garage to the other side of the garage and down to the trench, can I run it through metal conduit on the outside of the garage under the eaves and down to the trench? I don't have access to the garage attic, and don't want to tear up the sheetrock to run through the walls...

Thanks!

That sounds like it could be a fair cable run. Be sure to run a voltage drop calculation, keeping the drop below 3% (rule of thumb). You may need to increase your wire by a size, depending on the result.

[Aleks Hunter]

Sorry Matt my reading of your last paragraph was kind of hair raising, picturing a plug end on a length of romex and coiling it back up when done. To minimize VD to protect your tools go with the 6/3.

As for your last question, check your local code for what's doable. and PVC conduit will save $$ vs metal if its allowed. Keep in mind that the longer the run the greater the VD.