How do I add electric to a new garage built?

[PI Lvr83]

I am having a barn type garage built as we "speak". They will be putting up Hardie Boards (cement type) on the outside. The base is concrete. I want to put 110v/15 amp out there.

I currently have a small aluminum siding shed that I ran electric wire (type that can be buried) about 10 years ago. Has been working great. I added a 15 amp circuit breaker to my house breaker box.

Now next to this shed (will have removed) I am building the permanent garage. Can I add splices or wire ties to the current wire to add length to make it to my new garage? I don't want to did up the yard again if I don't have to.

My biggest question is how do I get electric to the building? With my shed I drilled a hole in the wood floor and brought up the wire that way. With the cement siding and concrete floor.

My two questions: Can I add a splice (put splice in PVC and seal both ends?) to add lenght?
How do I get the power inside the building with concrete floors and cement sides?

Thanks,

GregView media item 30201

 

[matt151617]

You'll have to cut into the cement boards and put conduit through them. You can't splice the wire that's already there, but you'll have to upgrade the wire anyways because 15 amps isn't enough. Get #2 mobile home feeder and a 100 amp subpanel (with a main breaker on it).

Since it's a detached building, it's going to require a subpanel with the ground and neutral isolated from each other, along with 2 ground rods.

Yes, you have to dig up the yard again, to a minimum of 18 inches depth. They should have left a piece of rebar sticking out of the slab for a ufer ground. As always, make sure you get the proper permits and follow local codes.

 

[pattenp]

Too late now but you should have put a PVC sleeve in the concrete pad to get the wire to the inside. You can splice the UF but you must use a splice kit made for under ground. The wire where it will come out of the ground will need to be in PVC conduit to where it enters the building. You will need to drill a hole in the wall for the wire to enter.

 

[pattenp]

All he asked was how to extend the existing 115V 15A circuit.

You'll have to cut into the cement boards and put conduit through them. You can't splice the wire that's already there, but you'll have to upgrade the wire anyways because 15 amps isn't enough. Get #2 mobile home feeder and a 100 amp subpanel (with a main breaker on it).

Since it's a detached building, it's going to require a subpanel with the ground and neutral isolated from each other, along with 2 ground rods.

Yes, you have to dig up the yard again, to a minimum of 18 inches depth. They should have left a piece of rebar sticking out of the slab for a ufer ground. As always, make sure you get the proper permits and follow local codes.

 

[PI Lvr83]

... They should have left a piece of rebar sticking out of the slab for a ufer ground. As always, make sure you get the proper permits and follow local codes.

I did not know what a ufer ground is so I looked it up on Wikipedia. I do not have a bar sticking out of the concrete but do have those "J" bolts that the frame sits on. Would this suffice as a ufer ground? I did not have a ground in my current shed. I did use a GFI outlet though.

 

[pattenp]

The J bolts can't be used as a ufer ground. If you are just extending the one 115V circuit you don't need a ufer ground or electrode grounding system. What you need all depends on how much power you want and how may circuits you want. Just what do you plan on doing in the garage that you need power for?

 

[PI Lvr83]

I would like to have a light on the outside and one on the inside. I would like to be able to run a ShopSmith (once I purchase one!). I do not know how much amps I would need for a ShopSmith.

I just want power to tinker with. Currently, I use my 15amp for an outside light, inside light when needed, table saw, and router saw when needed. I have never popped the CB with these items.

My wife uses the power to run a weedeater from time to time.

 

[pattenp]

The Shopsmith will max out your 15A circuit. It sounds to me you need a larger feed to your garage. At least 30A. So now that's getting more to what matt151617 posted.

 

[VHF]

As was already mentioned, you can extend your existing underground circuit using special underground splices. The type of wire that can be burried is called UF (for "underground feeder".) You should use 12/2 UF to extend your circuit (which means #12 wire, 2 conductors + ground.) It should be burried 24" deep unless you put it on a GFCI breaker at the house, in which case 12" deep is sufficent.

The standard way to add power to a existing structure is to use PVC conduit on the outside. Starting in the trench, you should have a long-sweep 90 ell, a vertical length of condit going up the wall, an LB conduit body, and a short length of conduit to feed through the wall. Inside you need to have a means to disconnect the power to the building, typically a circuit breaker panel.

As already discussed, a single 15A circuit will let you run a couple lights and one power tool at a time. What is the total distance from your house to your new building? The longer the distance the greater the voltage drop, which can be significant with a large motor load.

 

[PI Lvr83]

...What is the total distance from your house to your new building? The longer the distance the greater the voltage drop, which can be significant with a large motor load.

The main house is about 85 feet from the garage.

 

[eddie1278]

call an electrician

 

[matt151617]

He need to drill a hole into the building, he needs to dig a trench to extend the UF... might as well do it once and do it right... conduit, larger gauge wiring. Even do #6 if you don't plan on ever running much. 15 amps isn't going to be enough if you actually want to use it as a garage.

Also, don't forget all outlets need to be GFI.

 

[rburke65]

I second the vote of calling an electrician!

 

[Charles (in GA)]

You really need to rethink what you need for power in your shop. You spent the money to build it, and plan on using it, but it sounds like you don't think you need electricity in it.

A reasonable plan would be at least a 60 amp subfeed to the building, which you can branch off of via a subpanel, which will give you power for lights, radio, saw, fan, etc.

15amp 120v is what you might run to a storage shed to operate one light. Even to a storage shed, I would run a MWBC (240v with a neutral) just to play it safe.

You never wake up in the morning saying "dang, I put too much electric capacity in the garage" but you sure will be thinking " I screwed up and didn't put in enough power" when the breaker trips and you have to hike to the house to reset it, or the saw starts slow because the lights and fan are on.

Charles

 

[CNGsaves]

Show us what you've got so far . . . . pictures tell a lot.

 

[tylernt]

The main house is about 85 feet from the garage.

What gauge of wire did you bury? The thickness of wire will determine if you can go that far with the existing wire.

Also, does the existing wire have black+white+ground, or black+red+white+ground?

 

[PI Lvr83]

What gauge of wire did you bury? The thickness of wire will determine if you can go that far with the existing wire.

Also, does the existing wire have black+white+ground, or black+red+white+ground?

Sorry for taking so long to get back but was sent TDY for my job. The wire I have is Black+White+Ground.

What gauge I have, I don't know but it was made to be buried. I bought it from Lowes.

 

[PI Lvr83]

You really need to rethink what you need for power in your shop. You spent the money to build it, and plan on using it, but it sounds like you don't think you need electricity in it.

A reasonable plan would be at least a 60 amp subfeed to the building, which you can branch off of via a subpanel, which will give you power for lights, radio, saw, fan, etc.

15amp 120v is what you might run to a storage shed to operate one light. Even to a storage shed, I would run a MWBC (240v with a neutral) just to play it safe.

You never wake up in the morning saying "dang, I put too much electric capacity in the garage" but you sure will be thinking " I screwed up and didn't put in enough power" when the breaker trips and you have to hike to the house to reset it, or the saw starts slow because the lights and fan are on.

Charles

Wow, "enough said"! You make a very good point. I will listen.

 

[tylernt]

Assuming the stuff you bought is 12ga, you can go 85ft with it if you use a 15A breaker. Barely. Run 12ga inside the garage too, because you're right on the edge of permissible voltage drop.

If you got 14ga, there's too much voltage drop so I'm afraid 14ga is no good.

I agree that some fluorescent (either T8 or curly bulb) and a ShopSmith is going to max out a 15A circuit. It'll work (I did something similar), but have no room for anything else, for example running a dust collector while the ShopSmith is running.

 

[rburke65]

You need to seriously consider running a larger feed to your shop/garage. Charles ( in Ga.) knows of what he speaks. I know.....none of this stuff is inexpensive. Do it once and do it right. Good luck.

 

[NickFrands]

It is best to call experts when it comes to electric connection to be on the safe side. We may know all about electric circuit but hiring some experts will guarantee that your place is in safe hands.

 

[matt151617]

I can give a perfect example of this. I have a 14x25 shed in the far back yard. It is powered by a circuit on a subpanel in the garage, about 75 feet away. Whoever installed it decided it'd be easier to direct bury UF, and also split the connection at a deck to power the pool. Over the years, a large patio and deck were built over the buried UF, making it impossible to ever dig up and replace without a ton of work.

The pool pump/shed circuit is on a timer so the pump doesn't run 24/7. So for 16 hours of of the day, there's no power to the shed, unless I unplug the pump, and turn off the timer. When there is power out there, I can't run any saw or large power tool unless I turn off the pump first.

Do it right- put a larger circuit than you'll need.

 

[VHF]

The pool pump/shed circuit is on a timer so the pump doesn't run 24/7. So for 16 hours of of the day, there's no power to the shed, unless I unplug the pump, and turn off the timer.

Move the timer out to the pump location so at least you can have your shed power on 24/7. (You'll still need to turn off the pump to run large power tools.)

 

[matt151617]

Move the timer out to the pump location so at least you can have your shed power on 24/7. (You'll still need to turn off the pump to run large power tools.)

Timer would need to be outdoor rated, etc... I know, there's ways around it, but it works fine now, just a couple extra steps. Just using it as an example.

 

[PI Lvr83]

Show us what you've got so far . . . . pictures tell a lot.

That is my problem. I do not have anything to show. I want to add electrical. to give you an idea here is the inside.View media item 30655