Where to come in with electrical

[Mdaddyrabbit]

I have attached a crude drawing below to help illustrate my question. The building is 30x48x12. I was thinking of entering the building with the electric on the side since it would be somewhat of a straight shot from the house. The only thought question is this, that would make it where to get over to the other end, the building would require more 12/2 wire to reach and would that drop amps because of the long 48' run. I thought about going around to the back of the building and coming in there. This would be half way and consume less 12/2 and not worry me about volt or amp drop off. Since I am not an electrician I have no clue about voltage or amperage drop off.

The two goals I am looking for is not having so many long runs of 12/2 to save money and also make sure I have enough current.

If this were your building and you were going to wire it which direction would you take this?

 

[79firebird]

Only one circuit is permitted to a outbuilding. So i would go sub panel right on the side.

 

[pattenp]

I'd do the straight shot to the building. As long as you size the main feeder to have negligent voltage drop for the total building load then runs of branch circuits within the shop of upwards of even a 100 feet each should be no real problem.

 

[Mdaddyrabbit]

Okay, would you on long runs to the far end of building use larger wire other than 12/2

 

[justsam]

Okay, would you on long runs to the far end of building use larger wire other than 12/2

I'm not sure if yu understand what 79firebird has stated. If you are going to have more than one circuit inside your garage, you need a sub panel. All the circuits inside your garage will be fed from this sub panel.

You need to determine what your power requirements are for inside your garage. That will determine the size of wire required to feed your sub panel from the house. So what will be in use in the garage? Air compressor, welders, hvac, etc.

Assuming that inside the garage you need 20 Amp circuits, the 12ga wire you mention will not need to upsized for longer runs within the building.

 

[Mdaddyrabbit]

I'm not sure if yu understand what 79firebird has stated. If you are going to have more than one circuit inside your garage, you need a sub panel. All the circuits inside your garage will be fed from this sub panel.

You need to determine what your power requirements are for inside your garage. That will determine the size of wire required to feed your sub panel from the house. So what will be in use in the garage? Air compressor, welders, hvac, etc.

Assuming that inside the garage you need 20 Amp circuits, the 12ga wire you mention will not need to upsized for longer runs within the building.

I am going to come off the main box from my house which is 200amp and go to my building with a 100amp main breaker box. I understand that. My questions is this. I really want an opinion. Should I put the sub box at my building on the side wall or the back long wall? My only two concerns with placement of sub box is the amount of wire it will take for receptacles and lights if I go from one end of building to the other. If I mount the sub box half way on the back side of building then I am in between. I don't know how much current drop off there would be from one end of building to the other. I am not trying to add multiple sub boxes to the building.

 

[sberry]

These are NOT long runs, v drop with 12 is not a problem in this garage. Its what you should be using for recept circuits.

 

[pattenp]

Okay, would you on long runs to the far end of building use larger wire other than 12/2

For a 20A multi-outlet circuit the 12-2 is fine for the distance in your building. The thing to consider is the total load that will be concurrent on any individual circuit. You may need to run more than one 20A branch circuit to the end of the building to divide loads. One way to do this is to run a multiwire branch circuit and alternate outlets along the run. The multiwire branch circuit needs to be fed from a double pole common trip breaker.

I think some are confused thinking you're asking about running multiple #12 feeds from your 12 circuit panel at the house to the out building.

Edit: You haven't said what you are planning to use these #12 circuits for at the opposite end of the building. Just general purpose outlets?

 

[Mdaddyrabbit]

For a 20A multi-outlet circuit the 12-2 is fine for the distance in your building. The thing to consider is the total load that will be concurrent on any individual circuit. You may need to run more than one 20A branch circuit to the end of the building to divide loads. One way to do this is to run a multiwire branch circuit and alternate outlets along the run. The multiwire branch circuit needs to be fed from a double pole common trip breaker.

I think some are confused thinking you're asking about running multiple #12 feeds from your 12 circuit panel at the house to the out building.

I must didn't explain myself right. I really had them confused. I lucked up thought. Our company electrician came by for some computer work and I got all my answers answered.

 

[bczygan]

I must didn't explain myself right. I really had them confused. I lucked up thought. Our company electrician came by for some computer work and I got all my answers answered.

What were they?

 

[Kaizen]

the only real issue/savings to consider for that length and that size garage is how many circuits are going to come out of the sub and where they will be going. so for example if you have 2 car bays for parking and the rest is a woodshop then putting the panel in the woodshop would be better so you have less wire to run all your outlets. if on the other hand you only will be doing metal work at the close end with big 220 machines then that is where you should put it. in a garage the savings will be small either way. good luck