wiring an outbuilding

[Nick Letts]

Hey Guys,

I just found this forum and am happy to find a forum that has actual knowledgeable people on it.

So here is my plan (sort of) and I just want any advice you guys can share. I have a prefab 12x20 building about 70 off my house. It came wired with 2 lights and an outlet. I plan on using this as my wood shop. Everything I have runs off 110 and its just me so there is never more than one tool running. Also I know it not ideal but for know I can except a extension cord on the floor because I don't have a lot of cash to buy conduit and outlets to do the inside yet. I would like to put a light on the outside that I can run off a switch by the back door of the house.

ok so hear is my plan....let see how wrong it is

install 20 amp breaker run 12-2 into a switch by the back door.

run 12-3 uf from the switch box outside in coduit down to a sweep than lay the wire without conduit across a 18 inch deep trench. bury caution tape at 12 inches. back into sweep up into the building. Sound ok??

is 12 gauge ok even with the 70 ft run?

anything else I need to consider?

Thanks

[Robert Meier]

Let's start with the first thing, are you filing for this job and having it inspected?

[Nick Letts]

Hadn't really thought about that yet. I want it up to code either way...

[Jim Port]

I think that you would be much better off having a small 40-60 amp subpanel installed. Much greater capacity and versatility. The 20 amp that you propose is too limiting.

[Kenneth Dolin]

Agree with Jim. Sub panel is the way to go. You really need to have a disconnect at the destination. might as do it right the first time.

[Nick Letts]

Thanks for the input. In no way am I questioning your knowledge but what do mean by too limiting? I mean obviously it has limits but I don't really plan on pushing those limits. Like I said its just a small place and just me. Just trying to understand better. Putting in a subpanel will cost me a lot more wont it? Does anyone have a good guide for installing one?

Barry.......I live in a rural area and we just fall under NEC. there are no requirements to pull permits.

Thanks again you guys

[Robert Ernst]

Barry good questions and your on the right track by asking questions first. You seem like you want to do it right so that's what you need to do. One thing you always need to remember is that it will cost you more to fix it later. If you go to sell some day one of us is going to be out there to inspect and then things done wrong bite you. Go to the local building department. Pull a homeowners permit. Ask them for direction. See if the Building Inspector will come out and give advice. Some of them aren't the nicest guys but you might just have to deal with it. I would run the wire in plastic conduit. Maybe rent a ditch machine and run water or gas pipe also. As your installing the conduit you can put the wire into it if you don't have a long fishsteel. Get a breaker for your current panel. Maybe a 50 amp. The size the wire accordingly. Go to Home depot and buy panel they are $50 and some come with some breakers also. The panel will be rated for 125 amps but that is the max. If you put more than 6 breakers in it buy a main disconnect. They sell ones you can add to the Homeline panels they sell at Home Depot. This keeps you from running all the way back to the house to shut down the whole shop. Put all your lights on one circuit. This way if you trip a breaker while working at night your not in the dark. Also Make sure you have a outside light by each door. Lastly get on craigslist or the yellow pages and get a licensed electrician to come out and make the final connections and check you work. If you need any more info feel free to ask. I have a 1000 sqft wood shop behind my house and I've done all this already.

[Nick Letts]

So it seems like you guys are saying I can't do it the way I thought but without saying so.........Does my idea violate code somehow? I assume I am required to have an entrance light outside the door from what you said?? As I said mine is no where near 1000 sq ft its barely over 200.

Again I totally understand what you guys are saying about just adding the panel. and I would def not run into issues if I sell.



Was really hoping this would just be a simply project to get some power and light out there but I guess there is nothing simple about it??

I really appreciate all the help from you guys.

[Paul W. Abernathy]

However, since you are here....

1) I see nothing wrong with your plan except you don't need the tape in the ground.....that's for service conductors.
2) I would also recommend a remote distribution panel in the shed but again you said you are on a limited budget so skip that....
3) Since you are limited, run a 10/3 w ground in UF to the shed, protect with 20 amp ocpd and make sure you install a disconnect for both ungrounded (hot) conductors at the shed.

As for fixing it for the future....that's your choice and budget. If you don't have the money today....then do what you can afford as its your money and your needs you are designing for.

[Nick Letts]

I really do appreciate all this help guys.......

How much more will it realistically cost to run the sub panel?? its about 100 ft from the main panel?

I guess I need an outside light also?? Anything else required by code? Does that light need an outside switch???

I am tight on cash but want to do it right the first time.

Can I run water line in the same trench as electric???

Can anyone point in the right direction for this project as far as references for code etc?

How big of a breaker do need to run the sub panel off? what size wire from panel to panel??

I assume each circuit needs a gfci at the beginning since its outside??



I really appreciate it

[Robert Ernst]

I understand you want it cheap and easy but this is electrical and it needs to be done right. So with your original plan. You will need a means of disconnect at the building and I'm pretty sure UF needs to be 24" deep if it's not covered by concrete or a driveway. You can use 12 ga wire up to 100' as a general rule but you can look up the mathematical calculation.

[Paul W. Abernathy]

Honestly...I don't see where it is cheap. Only HE knows his needs. As for the depth when I make a reference to 20A I am assuming he is going to GFCI protect the circuit which would reduce his depth to 12 inches and so his 18 inches would be fine. However, if he chooses not to then he needs to dig a little deeper...lol

Reality is the National Electrical Code provides for this not because it is a cheap option...but because it is indeed an option.

[Robert Meier]

Originally Posted by rernst1

I understand you want it cheap and easy but this is electrical and it needs to be done right. So with your original plan. You will need a means of disconnect at the building and I'm pretty sure UF needs to be 24" deep if it's not covered by concrete or a driveway. You can use 12 ga wire up to 100' as a general rule but you can look up the mathematical calculation.

Actually for UF cable it's 18" at one and two family dwellings even if it's under a driveway. You can reduce that dimension to 12" if the circuit is not greater than 20 amps and GFCI protected.

As mentioned you'll need a disconnecting means nearest the entry of these conductors into the building.

Any installation beyond one circuit (sub-panel) will require that a grounding electrode system be installed at the secondary structure.

If you're wanting to only use UF cable that's fine since it's cheap and installs quickly. I would run an empty 1" PVC conduit in the trench while I have it open just for the future. PVC is very cheap.

[Robert Ernst]

Robert, can you tell me where I can find the info that states uf can be that shallow. The way I read the NEC table 300.5 is that it's 24". Has to be protected in conduit down 18" and up 8'. I do agree with running conduit and I would eliminate the UF all together.

[Robert Meier]

Originally Posted by rernst1

Robert, can you tell me where I can find the info that states uf can be that shallow. The way I read the NEC table 300.5 is that it's 24". Has to be protected in conduit down 18" and up 8'. I do agree with running conduit and I would eliminate the UF all together.

Sorry the numbers should have read 24", except under driveways and parking areas of one and two family dwellings which is 18".