How To Shop wiring

N.W. Gean

N.W. Gean

Joined
Oct 10, 2018
Messages
455
Hi and happy holidays to everyone,

The time has come to wire up my shipping container shop, but we're not quite sure what wire needs to be run from the main breaker pole (I own this part, not to worry). We know that we need at least 6 gauge (4 preferable) to power my heat treat oven and grinder. It's a 50 ft run into the shop plus another 40 or so to the back where the grinding room is. There seems to be many different types such as Romex and the like.

Just curious to see what those who have wired up their own shops have done.
 
I don't know what your total amps are for the entire building which is what that main wire should support to a sub pane inside the shop, but Google is your friend. A search for a wire size/distance chart should help you.
 
First off congratulations on your new storage container shop and for being in the market for wire at the absolute worst time in this century. LOL Seriously I'm assuming your ditching between home and shed. You have two options for underground. Direct burial or PVC conduit with individual conductors. Most folks use direct burial for cost reasons. The minimum service I would run in copper would be 30amp 10/4 UF. You would be capable of 240v 30 amp sub panel. Cost wise your ahead to just buy 100 amp mobile home aluminum feeder capable. It's also called aluminum 2-2-2-4 stranded MHF. You then could have 240v 100 amp sub panel for probably the same price as 10/4 UF wire. Don't even price 8/4 or 6/4 UF unless you have a winning lottery ticket in your pocket.

As stated both are for direct burial but if your crossing a drive way or area subject to damage you can slide PVC conduit over it as you lay it in the ditch. PVC pipe is ridiculous in price also. Good luck.
 
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LCoop said:
being in the market for wire at the absolute wrong time in this century.
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Tell me about it...

LCoop said:
I'm assuming your ditching between home and shed.
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Yes
LCoop said:
Cost wise your ahead to just buy 100 amp mobile home aluminum feeder capable. It's also called aluminum 2-2-2-4 stranded MHF. You then could have 240v 100 amp sub panel for probably the same price as 10/4 UF wire.
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Now there's a great idea. The feeder is a bit cheaper and gives more headroom in amperage. Thank you!!
 
I recommend 2-2-2-4also. It is good for 100 amps at your distance. It wires into the sub-panel breaker box in the shop. From tere run all thge lines you need in appropriate grades. 14ga for lights, 12ga for normal 110 circuits and 10ga (or even 8ga) for heavy draw circuits.
 
For burial I would for sure put in PVC for protection of the wire. That much PVC isn't going to be all that expensive and it will help prevent damage in the future when digging for planting bushes, plants, etc. I know you don't expect that to happen, but it will.

My own experience a few yr back I ran new wire from main distribution panel to the sub panel in the "radio room" and for cost reasons I used aluminum direct burial. Since this cable was buried right up next to house foundation I used direct burial cable with no PVC pipe. After all, it's next to the concrete foundation, no more than 6" away. Perhaps a yr later the wife hired a landscaper to do some work. He was digging in the area, I didn't think anything about it. About a yr later I lost 1 phase of power in the sub-panel. Started chasing the wire, and where he was digging the insulation was scraped down to aluminum wire allowing water to the wire. During that year corrosion started and broke the aluminum wire. Had it been copper wire most likely wouldn't have been a problem - maybe. For sure if I'd put in PVC pipe everything would have been ok.
 
Thanks for the replies and new ideas! This is why I come here!

I agree, conduit is a must. That was part of the plan :thumbsup:
 
When I was doing the same thing, I was told that if I used aluminum wire, I should plan to check the connections every 6 months or so because aluminum expands an contracts with temp changes and you might have to tighten the threaded connection to the breaker.
 
I always bury the wires in 1.5" or 2" gray PVC conduit. It costs so little it is a no brainer. I find the pre-twisted 2-2-4 easy to work with when running down the PVC.

I learned to do it this way the hard way:
Dig the trench
Run the wires from the power box to sub-panel through ALL fittings and the pipe sections BUT don't glue up yet.
Check that all connectors, bushings, locknuts, and other fittings are in place ON THE WIRE where they belong.
When all is ready to hook up on both ends, glue up the PVC, fittings, etc..
When both ends are connected and all is working right, fill the trench.
 
Instead of running my own line from my house to the shop I called the electric company to run the line and install a power meter on my shop... Then I did the internal wiring and put a 200 amp panel in. I don't think they charged me iirc, or if they did at the most it was a couple hundred dollars. It is also very helpful wine it comes to business taxes as there are no muddy waters
 
If you have soil with sharp rocks pvc pipe is best but there are options. Direct burial wire in aluminum is probably 1/4 the cost and its fine if your conditions are right for it. You can use sand below and above it if there are places of concern and this is up to code in most areas. Theres a recommended burial depth as well usually 2 feet. Can you meet that if not pvc for sure. Will you require an inspection at some point?


aluminum comes with its own issues some boxes are not compliant with aluminum so you have to know if your source box allows it. If your supply box is not rated for aluminum you now know what your wires going to be.

calculate your total load there’s plenty of on line sources to give you specs but its really more relative to what you will have on at once and more to the point what consumers will be starting and stopping at higher loads at the same time. Motors can draw a lot more current loaded on start up than just running a power hammer thats loaded and unloaded often may have a high surge load what else will be on at the same time. wire size is altered greatly on run length make sure you measure for curves it will be longer than you think. make sure you have the correct size wire for amperage and run length and aluminum and copper will be different sized wires.


if You go with pvc use at least one or two sizes larger pipe than what that pipe specs i think the charts are not right on number of wires a given pipe size will hold. Pulling wires is easier in a larger pipe. Here’s another factor direct burial wire runs cooler than in a pipe. So there are reasons direct burial is ok.

one last tip is to make sure you understand ground and common wire uses. Common wire cannot be bonded to ground accept at the first point of origin Which may not be the breaker box you connect to. This is an area that many people wire wrong and it is not safe.
 
weo said:
When I was doing the same thing, I was told that if I used aluminum wire, I should plan to check the connections every 6 months or so because aluminum expands an contracts with temp changes and you might have to tighten the threaded connection to the breaker.
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IBEW LU#443
Epcot (sp?) of Disney was done in aluminum. It was a flop in residential branch circuits because aluminum must be retorqued periodically.
I like running the biggest wire that can be fitted and the overload protection @ the recommended amps for service and branch loads, because you will not have to worry about nuisance tripping.
Make sure that you have tight connections and twist the conductors tightly together before you use wire nuts. Think of wire nuts for insulation. This is the cause of most electrical fires.
Spending good money and planning the work is worthy of your investment.
 
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