Hi all,

I have been working on pricing a quote to run power to a detached shed. The shed is about 105' from the main panel. The run will be along the side of the house then under the deck and the rest of the way underground. The owner wants two receptacles (one outside) and three light fixtures.

Initially the thought was to run one 20 amp circuit but with the voltage drop I'd have to use #6 wire which wouldn't fit into the 20 amp breaker in the main panel. So what I've ended up with at this point is the following:

A 60 amp d.p. breaker in the main panel, 2-2-2-4 SER cable along the house, and then 2-2-2-4 URD cable for the rest of the run. The portions of the URD which are above ground will be in 1-1/4" PVC conduit. Inside the shed will be a 100A 40 space load center with the main breaker changed to a 60A. I think this will all work, but is obviously overkill.

So I have two questions, really. Are there any problems with my approach? And is there a cheaper or easier way to do this? He really only needs a single 20A circuit.

Thanks,

Brad

The #6 can be spliced to a number 12 at the panel and at the first outlet. The foot or two of #12 will not adversely effect the ampacity of the circuit but will solve the voltage drop.
BTW I got #8 for a %3 volt drop on a 20 amp load 105 feet away.

I agree with mike about the #8 but I might go with a #10/3 and a multiwire 15a circuit which takes all of these problem away (you still end up with 3% V/D worst case and half that with a balanced load).
It also gives him the flexibility of having 240v out there.

Yes those sound like much more cost-effective options. I was unaware that I could switch wire sizes to counter the voltage drop. I believe the table I saw was sizing wires for a 2% drop where both of you referred to a 3% drop. I surmise that the codes only require 3% then? I will be certain to confirm with the local inspector before doing the job in any case.

The code doesn't really require anything about voltage drop but 5% overall is the recommendation in the fine print note.
(3% for feeders and 2% beyond that feeder). If you are going from the main panel you could really say 5% but 3% is not bad.
You also should take into account what the normal load would be.

The multiwire probably gives you the biggest bang for the buck and it is still considered one circuit in article 225.

Thanks; that's very helpful. I think it does make sense to use the 10-3 UF-B wire for the underground portion. I'll transition to THHN in conduit for the portion under the deck and beside the building.

I read that a disconnect is required for each building, (farm wiring) but I don't recall ever seeing that in a shed/detached garage. Is that a requirement and if so can I use a standard toggle for the disconnect?

Thanks again.

This is in 225.36



So you can use a 2 pole snap switch marked as the disconnect.

"All I need/want is a single 120v circuit." Lest I sound too cynical, this question has been asked far too often - and just as often followed a few months later with "how can I get more?"

Remember, the NEC is not a design manual. There's no such thing as doing the 'code minimum;' such efforts always lead to trouble down the road.

So, what are you to do? Well, the first thing is to run your wire in a big pipe, and bury that pipe deep. You don't want to have to dig it all up again, the next time.

When the time for an upgrade comes, remember that you'll also have to pull a large ground wire, and you'll need to have a ground rod at the addition as well. Remember there's a difference between a 'branch circuit' and a 'feeder.'

Someone is sure to tell you that a certain wire is made to be directly buried in the dirt, or that you need not go down 30". Technically, they might even be correct. Yet, such a minimalist approach gives you absolutely no room for later changes. I advise you to bite the bullet now, and never have to dig again.

reno
How many times have I heard but we met the code! Early in my career as an inspector I had a consultant ask is everything OK to which I said it meets code but if you have a spec on the job you better check yourself.
To this day I have never seen him again and I wonder if he knew what I meant? Yes a lot of people think if it meets code it also meets need equally. I have had more than 1 discussion with owners disputing the contractor's work. They imagined a Rolls Royce and got a Neon. Both meet DOT requirements but the budget is different.

I think you can over do this shed thing if it is really just a shed. If this is big enough to set up a shop out there it may be worth pulling in a 60a feeder but most people will never do more than store some stuff and maybe want to plug in some hand held equipment.
If you really do think there is a future expansion in mind, pipe it, but to keep the bid reasonable I would still go with four #10 conductors.

Did anyone take the drastic step of asking the customer what they want?

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.

It's one thing when the customer is simply trying to say "I don't need very much, and don't want to pay for more than is necessary to make the job happen" .... and another when the jackalope is trying to figure out what lies to tell, what angles to work.

The examples given above of the town hall are good examples of the customer - in this case the accounting folks - not knowing what they want, but also being budget conscious. We all have numerous stories about jobs like that; my favorite is the office remodel where they want all the lights on one switch, because they think you charge only 'per opening.' (Later they fret that the entire place must be lit up when one guy is working late, or when the entire office goes dark when maintenance replaces a single ballast).

A more sinister example is the 'hair salon' I bid on last year. The moment the customer figured out that 'hair salons' had special electrical and ventilation needs, he suddenly changed his plans. The city was only asked to permit a simple division of a retail space .... after inspection, amazingly enough, the place was rented by a hair salon. In this instance, the owner deliberately leased an inadequate space simply to avoid the code requirements - placing the burden on the tenant. All my bid accomplished was to teach him what lies to tell.

That, of course, is why I brought up the topic of 'what is REALLY going on in the garage." When someone asks "what's the least I can do," the stage is set for disappointment. It would be irresponsible to answer, without first learning just what the guy is trying to accomplish.

Another example is when an owner has built a nice 2 story office building. He has tenants on the first floor,They are a doctor and an optician. So the owner decides to finish off the second floor and get more tenants. Now does he install wiring as per sec. 517 of the NEC or does he just install regular wiring. He doesn't know what type of tenant he will get for that second floor space. Ihave seen it done both ways. If he gets another tenant that needs 517 wiring, he will have to remove sheet rock and start all over again.

Yes the customers motivation is always a challenge. I know contractors that will tell a customer that if he wants to build a suite in his basement that it better have a building permit or get another electrician. and there are electrical contractors that will work to decieve the municipality by declaring 1 purpose and after the final inspections are complete cut in the range and counter outlets from the circuits he hid before drywall was installed but after those inspections. Often both installations are completely safe but 1 is stained with decpetion that often sticks to a future owner.
Most developers are looking for short term profit so they spec minimum, often neglecting the potential cost and grief the customer will have once they realize the suite and the main occupancy share a meter and are now constantly arguing with their tennants over electrical usage.

As soon as i mention Electrical permit for these types of installations I dont seem to get the job so yes there is other contractors that are getting this work but i assume it will eventually go south on them.

One other thing to remember is the customer will likely have motor loads (circular saw, lawn mower, etc.) on the tail end of a 100' orange extension cord plugged into that shed. That's where voltage drop can become a real issue.

mikesh,

You talk about contractors finishing off basements etc without permits, lately the Realtor look for permits for finished rooms and they come to the town hall to make sure that a permit was taken out. If they don't the next seller of the house is responsible for the finished area. They will have to pay the back taxes on it, and the building permit and the fines for occupying an area with out a certificate. When my town finds a room finished with out permit, we go out a look at the job, the job will always fail until the owner gets permits, pays the fine, then they have to get licensed people in there to check out all of the hidden wires, connections etc. Then we will come back to the job and see if it then makes code. We look for missing outlets, GFI protection, etc.

Looks better than what we do. No political will to persue a lot of these un-permitted jobs. Usually wait for a complaint or unavoidable discovery or catch them in the act.
A problem with a property does go to the new owner but if the vendor delared the truth about the property IE the suite was build without a permit (pretty common answer too) then the purchaser also buys the risk of getting caught and having to return the building to legal use or converting to the desired and already built room, suite, accessory building or what ever was done without a permit.
It gets very messy and every case is a custom job regardless of all the policies and laws we might have.

The Lee County Property Appraiser is pretty good about catching anything you can see from outside but they don't tell the building department about it. They just tack the appropriate "tax units" on the tax bill.

I often wonder what the result would be if the building department did try to come back on someone who had been paying taxes on an illegal addition for a decade or so.

Harold:
Our CCO inspector (non-DCA, non-UCC) scans the Twp files for any 'open' permits, and a back record of any/all work performed with permits before he goes to do the CCO inspection.

He can average 2-3 non-permitted finished basements, or other things each week. Replaced panels, furnaces, water heaters, AC, alarms, etc. are also 'discovered'.

He came on one a few weeks back that was finished 20 years back!

The HO applies for permits (B/E/F/P), provides a letter that they are aware of the existing condition as un-permitted work, and are subject to a fine.

If required, licensed contractors are required to correct any code violations discovered upon the inspections. A few (over the years) had to be ripped apart, some are OK.

That all said....this thread has to get back to the OP's topic.