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Discussion Starter #1
Hello,

First post here.
I bought a house and it has a building out back. The previous owner has electrical wiring running from a 30 amp breaker from the main panel to the building. Inside the building he has the wiring going to a single 60 amp breaker and is using one side of the breaker to wire in the 120 V sockets and lights.

I want this to be done properly so what should I do? Buy a proper panel and put 2 15 amp breakers? Or something else? I am building an addition onto the building a will be running more sockets and lights.

I had a heater running out there and I am assuming it burnt out the electrical socket as it no longer works, and the breaker he was using was a single 60 amp breaker with the sockets only being 15 amp rated. The other sockets still work.

Thanks for any advice
 

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The way it is now, it is certainly not to code. You can't have a 120V outlet or lights on a 30A breakers.



If you want to have multiple circuits, you need a subpanel in the outbuilding. For that, you will need a cable that has 3 conductors, plus ground, feeding from the main panel. Sounds like you probably don't have that now.
 

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Sounds like there is only 120 volts.
A panel is your best option. Half of the breakers will not function since you only have 120 volts, but that is no problem. Just use the live slots.
Regular duplex receptacles can only be on 15 or 20 amp circuits.
 

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Discussion Starter #4
There are 3 wires running to the building a red, a black, and a ground. I thought it would be 220 volts, because from the buliding to the main breaker panel it is tied into a 30 amp 220 breaker.

And in the building they are using only one side of the breaker to supply the 120 volts
 

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Discussion Starter #5
Would it work if I were to replace the breaker at the main panel with a tandem breaker? Only thing is the wires are much larger than the standard 12 gauge used.
 

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Discussion Starter #6 (Edited)
Sorry for all the post. But I wanted to correct that earlier post. The building has 4 wires going to it a Red, Black, Ground, and White.

Here is a photo of the box they currently have in the building.
Also thanks for the help.
 

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You are in luck then; your best bet would probably be to make this a sub panel with individual 15 or 20 amp circuits.

I would also check any existing outlets and junctions at this building for integrity since it is possible they have experienced an overload before.
 

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Discussion Starter #8
Thanks. Can I just replace the double pole breaker that is in there now with 2 15 amp breakers?

Or another thing I was wondering is if I could replace the double pole 60 amp with a double pole 20 amp and run 2 separate circuits one off each pole of the 20 amp double breaker?
 

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Naildriver
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You can only have one circuit to a stand alone building, so no to the two 15 amp breakers. As mentioned, you would create a sub panel of this and, assuming you will have no 240 volt applications, you can use 15 and 20 amp breakers in a lug box.

Seeing that you have a 4 wire set up, you can have 240 volt applications after all. What will be your load requirements in the building? Electric heat is a big hog, so we'll need to plan on that.
 

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Discussion Starter #10
OK I will not be using any 240 volt. I will be using 120 volt heaters and air conditioners. Altogether 4 lights and around 10 receptacles.

The box pictured above is what is in the building now do I need to replace it with a different panel? If so could you share an example?

Still not clear if it would be ok to use a double pole 20 amp double pole breaker in place of the 60 amp that’s in there now and just run 2 sepearte circuits? One off each pole of the 20 amp double.
 

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You could swap out your thirty amp breaker in the main panel with a 240V, 20 amp breaker and just Create a junction box at the old 60amp breaker at the building (thereby removing this breaker completely). This would give you a multi-wire branch circuit (MWBC) or essentially 2 20 amp circuits at the outbuilding.

However, since you have the larger wire, I would definitely consider installing a sub panel. Electric heat and A/C require large amounts of electricity to run would likely use most if not all of the capacity of a 20 amp circuit. It would also give you more control of individual circuits in the building.
 

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Discussion Starter #15
Try something like these:

https://www.lowes.com/pd/Square-D-12-Circuit-100-Amp-Main-Lug-Load-Center/3134331

https://www.lowes.com/pd/Eaton-Type-BR-12-Circuit-125-Amp-Main-Lug-Load-Center/3047889


If it were me I would have a dedicated 20 amp circuit in this panel for your heat and a/c needs. Then as many other general use circuits as you desire. Do you know what other appliances you plan on running in this building?
Thanks for going out the way to show what panels I will get the first one you showed as it is in stock at my lowes store.

I will run a dedicated 20 amp for the air/heat. Does it matter how many other circuits I have considering the breaker at the main is only 30 amps?
 

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Generally you can add as many circuits as you want, I would just be conscious of what all you want to run out there at the same time since you are limited. You could even make a list of all your loads with their power consumption to see where you stand.
 

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wNCmountainCabin
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sounds like the existing setup was wired for a 30amp 240v welder, or similar device, though I will admit that sometimes an electrician might accidentally wire this for a 30amp RV, which does NOT use 240v power.

Since you already have 240v power coming from your main panel in the house to this additional area - use a small sub-panel to complete your build, making it easy to then install several 15 or 20amp breakers for your circuits. Even though you may only have 30amps of 240v power coming into the new area, that is really just like 60amps of 120v power, which is really all you'll be making use of anyway for your 120v outlets and lights.

A sub-panel, like your main panel, takes 240v power and supplies it down two power busses, or power bars, which the 120v breakers attach to. Each 120v breaker only clips into one 'side' of the power, which means that each side can easily have either two or three 15amp breakers, or even several 20amp ones.
You might think that you have to try to stay 'exact' to what your incoming Amperage is, but that's not really the way most any main panel, or sub panel, is wired, since it's usually safe to say that 'everything' is not going to be running, powered, or 'ON' all at the same time anyway. You could have three 15amp breakers on one side, and a 20amp and two other 15amp breakers on the other side, with no issues.
A 20amp circuit simply gives you more wiggle room for those larger draw devices or appliances, like heaters, shop equipment with large compressors, etc. without nuisance tripping of the breaker.

I have an RV motorhome that is similar to your situation. It is a 50amp 240v motorhome, meaning that it plugs into a 4-wire 50amp RV outlet at RV parks and Campgrounds, and even here at my home.
Now, while the Campground's panel has 50amp 240v power coming from it, my motorhome's 'sub-panel' only uses 120v circuit breakers. What the RV manufacturer does, and just like you can do, is to have a 50amp 240v double-pole breaker as the main breaker, but feed each 'side' of the RV with only 120v breakers.
One side has 15 or 20 amp breakers for the electric water heater, inverter, air conditioner, etc. The other side has similar, for another air conditioner, engine block heater, the outlets, etc.
Even though the 50amps is available on each side, if you add up all the breakers on each side, you have a total that is well more than exactly 50 on each side, or even more than 100amps total, since not 'everything' will be on at the same time, all the time.

So, if you have a 30amp double-pole breaker in your Main Panel, which is feeding this 30amp double-pole 'sub-panel' in your new area, you will actually have up to 60amps of 120v to make use of.
If you decide later that you would like to power something in the new area that requires 240v power, you are still set up to do that. You would then just install a 240v double-pole breaker of the correct size in place of two of the existing ones, such as for a 15amp 240v small welder.
 
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