ECN Electrical Forum
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Let me say first I agree with Greg, ask the customer. Next put the run from the house to the shop in pipe. Pipe is cheap, digging is not, the difference in cost between 1 inch pvc and 2 inch pvc is not too drastic. I would run a 2 inch pipe for my power, and use the 10awg multi-wire circuit. Do a good job figuring your conduit route, keep the bends to a minimum then when you need to get 100, or 200 amps out there it can be pulled in without too much difficulty, and no digging. Let the customer know why the pipe is so big, they will appreciate it.

105' of #12 is going to have less voltage drop than the strung together #16 extension cords he's probably using right now. Unless this is a workshop with a bunch of 1.5hp tools in it, the easy solution is probably just fine for him. Even if he does have tools, the difference will not be whether the lights dim or not (they'll dim), but how much they dim. And that's probably less relavant to him than the extra $200+ the job will cost.


IMHO, the easiest run is to make this a single 20A GFCI protected circuit with 12-2 UF run in PVC by the house/shed, and maybe just direct-buried in the middle (though PVC is so cheap, no reason not to use it the whole way). If you put the GFCI outlet where it exits the house where, it will protect the whole circuit, including of the feeder: GFCI-protected 20A underground cable is only required to be 12" deep, even for direct bury. This is what I'd do if I was the HO.

Actually, come to think of it, it's exactly what I did for my own shed a few years ago... though I did put in a small panel with 2x 15A breakers to provide a little fault coordination.

Greg, I appreciate the artwork - timely as ever!

In my reply, I was going a step further .... one of the joys of contracting work is when the customer gets more 'clever' with each discussion. It seems they only learn what lies to tell. Lies, as in, "I only want power to my 240v pump in the pump house" or "I only want to store things and have the kids play in the basement."

Then, once the visible, inspected work is completed, it becomes "how can I find a cheap way to work around the rules to get what I really wanted." Things like additional circuits in the pump house or bedrooms in the basement (to kick up the resale price).

Not that I'm inferring anything about this particular OP; this thread will live forever, and any answers we give are sure to be picked up by others with similar desires.

Personally, I'm sick and tird of finding sheds 'powered' by lengths of Romex or extension cord that are 'buried' at grass-roots level. Or, for that matter, someone using the ground wire as a combined neutral/ground to create their 120v circuits.

The NEC is quite explicit: in article 90 it plainly states that simply complying with the code may not result in a job that can be readily changed for future needs. Somehow, folks nevr read that part.

Nor do they read or understand that the NEC is not a design tool....

One of the best examples is a comm bldg that used the six-switch rule to avoid the cost of a main OCP, and now needs additional metering, or feeders.

Salesmanship skills by the electrician or EC to 'upsell' the install for 'future use' is a great idea, but sometimes overlooked by a lot of guys

If this is truly a shed and not a barn, I see little reason why 3.6 KVA is not going to be enough (a 15a 120/240 #10 multiwire) but without changing a thing except the voltage drop concern, real or imagined, and a breaker, that could easily be a 20a multiwire, 4.8KVA or even a 7.2KVA feeder to a small panel.
My 230a buzz box welder has been running happily on a 30a circuit for 40 years.
We never determined the actual anticipated load here.
The NFPA wrote that single circuit rule for exactly this, a person who just wants some light and a receptacle or two out in their shed.
I understand we like to sell bigger and better but that does not accomplish much if the guy down the street gets the job by selling the customer what they asked for.

Greg:
I agree with your above statement, all I added was to Reno's comment.

Greg,

You talk about "What the customer wants?" Well in one of the towns that use to inspect for, I had to do plan review for the building. Being a commercial site, there is no code requirement for recpt. every 12 feet as is in resi. dwellings. So after the town hall was renovated, You should heard the people all complain to me that there wasn't enough outlets. Plus they said that I should fail the job because of it. I would then have to tell them all that "It meets the code!" but they didn't want to hear that. BTW, before work was started I told the town administrator that he should ask people where they are going to put their desks and where they might need more power. Needless to say,that didn't happen.

Harold:
That is a typical municipal description.

The planning stages usually do not include the workers, dept heads, supervisors. The 'bean counters' area is usually OK.

John,

Several years later in a different town that I still work in, the same thing happens. I tell Ad Min that if he wants me to review prints to the building he should avoid the problem of previous town halls. Ask the people what they want and where. This Ad Min. was smart enough to ask people to look at each office where they were going to work in. He asked for their input, he got it. there were still some problems but not as many.

Hey there Harold.

One day, just to make that exact point, I figured what would be the "Code minimum" for receptacles in the Sears Tower.
People were stunned when I showed that I would only use a few cases of duplex outlets, most of which would be in places that the office folks would never go (like Mechanical spaces).

It's unfortunate that the first reaction I get on many a job is "just put in outlets per the Code" and then I ask them if they also want a phone jack somewhere in their offices. That usually starts the conversation...and we start coming up with a workable layout from there.