Electricity to pole barn

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Old 07-30-08, 07:37 PM
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Electricity to pole barn

I am getting ready to install a Cutler Hammer BR style breaker box in my house. I am doing this because the previous owners upgraded the electrical system with a 100 amp box...but ran 4/0 wire which is good enough to run a 200 amp box. Why they only put in a 100 box is beyond me. Anyway, I have totally gutted the house and and rewiring everything as well, so I figure it will only be minimal work to go with a 200 amp box and I am going with the same Cutler Hammer BR style so I can reuse the pretty newer breakers I have. Soon I will be building a big pole barn out back, about 80 ft from the house. I would really like to be able to run 200 amps to the barn as well, to run big compressors, welders, car lift, etc. But I am not finding a cutler hammer 200 amp breaker. Is there a way to make it work with two 100 amp breakers, is there a 200 amp breaker froma different company that will work in the Cutler Hammer BR style box, or does anyone have any good relatively inexpensive ideas to get 200 amps to my barn? Any help will be greatly appreciated.

Thank You in Advance,
Eric Wheeler
 
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Old 07-30-08, 07:48 PM
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You wont find a 200 amp plug in breaker, you either need to find a feed through panel, or by code, you could run another set of service entrance conductors out to the pole barn, but you really need to do a load calc of the house and barn and make sure the existing service is able to handle the new load....
 
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Old 07-30-08, 08:22 PM
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I could do the load calcs tomorrow, although I am quite sure it'll be fine. My dad's house is done this way and his house is twice the size of the one I am currently wiring. His Westinghouse breaker box has a 200A main as well as a 200A breaker to supply the pole barn. But I guess Cutler Hammer doesn't make one, atleast in the BR style box? I guess I don't really care if there is a breaker in the house panel to cut power to the barn, I just assumed that would be the easiest. When you say another service entrance conductor...do you mean basically two cables coming from the meter, one going to existing house, then one ran out to the barn when it gets built? And if using a feedthrough panel, would I then have a total of 3 panels? the main house panel, fed to a sub panel, then that panel fed to the barn? Or did you mean 2 total panels, and I can feed through the main house running the cable all the way to the barn and then hooking it to a breaker box in the barn?
 
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Old 07-30-08, 09:44 PM
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I can't imagine why you would need 200A to the barn. This means you would need to run at least 4/0 aluminum out there if you are using a 200A breaker. If this is not a business and just you doing things out there, you can't be running a lift and welding at the same time, etc.

You don't just add up all the loads to a total. You have to take into account usage. If you added all the circuits ratings in a house up it would come to much more than the total panel main rating.

Why not use the 100A panel, now in the house in the barn. Install a 200 A in the house and feed the barn with a 100A or maybe even 80A breaker. You can still use 4/0 to the barn if you want and have less loss and future expansion if needed.
 

Last edited by dsc3507; 07-31-08 at 12:31 AM.
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Old 07-30-08, 11:12 PM
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I thought about running the 100A box out there, but it will be possible for the barn to use way more than the house at certain times. I didn't list everything I will have out there, just a few...other things such as a wood/metal shop and a paint booth with high power exhaust fans will also be out there. While it is not a business, there is always the possibility that a few friends will be out there working on projects at the same time, so I want the 200A out there to ensure there will be NOOOOO current draw problems...Say my friend is spraying furniture or something, then I kick on the welder which may dimm the lights, and he is spraying in a meticulous spot and messes up cuz the lighting changed...just a pain in the...Also I have had the problem at a friends barn, I was welding real thin metal, and the compressor kicked on, taking some power from the welder (even though on different circuits), and the welder was on such a low temp, that when power was drawn from it, it was no longer hot enough to melt the wire, causing a blip, which seems simple enough to just go back and weld that little blip spot...except now the metal was already hot, and I made it hotter by welding on it again and blasted through my sheet...wasn't happy...sure you're thinking just wait for the metal to cool back off then reweld the blip...but thats a pain, plus I'd prolly forget about it, and it wouldn't be noticed until it got in the paint booth...anyway...I just really really want to avoid any possibility like this. Which is why I am ALMOST considering 208 3 phase...but not so sure I want that electric bill
 
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Old 07-31-08, 12:28 AM
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OK, but you do understand that the things you cited have to do with loss in the wire and not the breaker. The breaker protects for total current draw. I still can't imagine you would need a 200A breaker. The wire size however could be larger. That is why I said 4/0 aluminum (3/0 copper), for the barn feed, which is 200A rated.

The question is will you be drawing over 100A at any one time.

You need to upgrade you house panel, that is a certain to 200A. Then you will have a 100A panel you can out in the barn. That is free. If you use 200A cable to the barn and this panel, you can always upgrade the panel later if you need to.

The thing I don't understand is how are you going to feed two 200A panels as you proposed from a single 200A service? If you put a 200A breaker in a 200A panel and you really intend to use 200A out there, then what is left for the house?
 
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Old 07-31-08, 07:22 AM
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I guess that all could work. Yes, most of what I described was prolly line loss. But if the buss on the breaker panel is only good for 100A, then that will cause line loss there as well. While chances are slim to none that I'd use more than 100A at any given time, it could be possible, I'm sure. If I kick on the welder at the same time the compressor kicks on at the same time someone kicks on the lift, while another person kicked on the spray booth exhaust...the list could keep going; again SLIM TO NONE, but not immpossible that all this happens at once...and electric motors take sixty times more power just to start up than to run for a full hour. Which is why the lights dim when you kick on your saw, or the A/C, etc but not a second later back to normal. I know I am being ridiculous about this, but I just don't want to have to worry about any of this, and if I have anything limiting current, it could happen. Also, like you said, if I have 200A out to the barn, what is left for the house...good point, again, possible, but even more slim to none chances that the barn and house at the same time would need the 200A, and if I am out working in the bar, do you really think I care if the ol' lady has enough current to kick on the vacuum while baking cookies? Do you know if 200A is limited at the meter? Was thinking of the possibility of having utility run a whole new line to the barn, but then I'd have 2 meters, and 2 bills, which wouldn't be bad, but they double up on the service fees as well, even though it is the same property and those greedy ^%&&*^&*^&^ turn enough profit from me. But if 200A isn't limited at the meter, then I should be able to tap in there and run a 200A panel in the barn without any problems, and wouldn't be drawing from the houses power availability and presto, my particularness is satisfied. I know my 100A box is free, but once I buy 100' of 4/0 or 3/0 and any other equipment, if I needed, any kind of switching boxes or anything...whats another $70-$140 for a 200A box?
 
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Old 07-31-08, 10:24 AM
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Originally Posted by HemiMoparGuy View Post
and electric motors take sixty times more power just to start up than to run for a full hour.
Not exactly. They draw about 6-10 times of the running current (amps) during start-up, but the power (volt-amps) is not substantially higher due to the depressed voltage.

if I am out working in the bar, do you really think I care if the ol' lady has enough current to kick on the vacuum while baking cookies?
You should care, because it will trip your main breaker(s) and you will lose power at both buildings.

Do you know if 200A is limited at the meter?
It is not limited by anything other than the melting point of aluminum, but you will damage the meter and/or service conductors if you exceed the 200A meter rating.

Was thinking of the possibility of having utility run a whole new line to the barn, but then I'd have 2 meters, and 2 bills
That is a reasonable solution for an outbuilding that uses as much power as you think you're going to need.

The only other option I think is appropriate would be to upgrade your house to a 320A (residential 400A) service and put a 200A panel in the house and a 200A panel in the barn. Trust me when I say that you won't like the price for a heavy up to 400A. Paying the extra meter fee for the barn won't seem so bad.

I'm still not convinced that you really need 200A in the barn though. I understand that you want to overkill, but it could end up costing you a lot to do so.
 
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Old 07-31-08, 01:58 PM
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I concur with all of the above. The main problem you want to solve will be unaffected by the solution you propose. The breaker size has absolutely no effect on whether or not the lights dim when a load comes on.
 
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Old 07-31-08, 02:17 PM
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I don't know the codes where you are but it would be best to run 4 wire cable (separate neutral and ground) from the house to the barn. At the barn end the neutral and ground are not connected. If you use the old box out there, they probably are. Remove the jumper and use a separate ground bus. You will also need to drive a ground rod out there also.
 
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Old 08-01-08, 07:13 AM
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Quote:
Originally Posted by HemiMoparGuy
and electric motors take sixty times more power just to start up than to run for a full hour.

[QUOTE=ibpooks;1406406]Not exactly. They draw about 6-10 times of the running current (amps) during start-up, but the power (volt-amps) is not substantially higher due to the depressed voltage.

I guess I will go back to the college I went to for electrical/electronics engineering and tell all of my instructors that said that motors take 60 times more power at start up, that they were wrong


Thank you everyone for all the advice and info, I guess I will have to do some research on the utility end and see what it will really cost me to do all the different possible upgrades to get 200A to my barn. Maybe I'll end up just throwing a 100A breaker in my house panel and running 4/0 cable to the barn and using the old house panel as the barn panel, and just make sure I leave enough excess cable to make it ovr to the the side of the house where it can be connected to a second meter, or connected to the residential 400A if I change over, if the 100A just doesn't cut it. I know I know...someone said right off the get go to use the old panel in the barn, but now I have several opinions and can choose an option "wiselier" than before.
 
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Old 08-01-08, 08:00 AM
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Whatever the answer on motor starting is, you would not size the wire and circuit protection for this starting current. It is a very short duration load. Circuit breakers naturally have a short momentary overload capability. This would be the same as using a time delay or slow blow fuse. It you sized the service for all the starting currents added up you mine as well run 10" copper bus!!!! It is natural and mostly unavoidable for a motor to noticeably dim lights when starting. What you are seeing is a very slight change in voltage. Only a few volts swing can be seen by the eye when watching an incandescent bulb. If the light is dimmed with a dimmer circuit you can even see more drastic light differences with very small line swings.

Again this a very short change, usually measured in milliseconds. It would NOT effect other things on the circuit like motors already started because of their inertia. The changes would be damped by that and unnoticeable.
 
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