200-amp Service to 100-amp Service

[vhcambrian]

I have a new 200-amp service that I want to run wire off of to the chicken coop. Can I just put a small panel with a 100-amp breaker?

There will be a two light fixtures and two to three outlet boxes and a motion light.

Thank you.

 

[Reach4]

The 100 amp breaker will be in the 200 amp main panel and wires including a protective ground run to the subpanel in chicken coop.

 

[Sponsor]

 

[vhcambrian]

Make sure I have this right.. I put the 100-amp breaker in the 200-amp box. Run my wire (what gauge?) underground to the coop, up the outside wall and into the coop... Then I buy and install a 100-amp sub. I need breakers in the sub, what amp? I am sure I can run those few things off one breaker. I plan on having an electrician hook it up to the main panel.

 

[Reach4]

Make sure I have this right.. I put the 100-amp breaker in the 200-amp box. Run my wire (what gauge?) underground to the coop, up the outside wall and into the coop...

I'll let you search that out. I could search for it, but you will get more complete info if you search. For direct burial, you can use something called UF (underground feeder).

I need breakers in the sub, what amp? I am sure I can run those few things off one breaker.

Typically 15 or 20 amps. You probably want to run 240 to the subpanel in the coop. That would let you add 240 volt heaters too later if you like. And yet you can have the 120 volt loads too.

 

[vhcambrian]

Thank you. I already know about the wire to bury. The electrician who installed the pole, panel and 30-amp for the travel trailer gave me instructions. I am just a researcher and want to make sure I understand and have everything right.

 

[Homeownerinburb]

I don't think you need a 100 amp service at the chicken coop. From your description a 30 amp service would suffice and then some. That requires 10 ga wire, which is a lot cheaper than what you need (#2 if memory serves, but look it up for yourself) for the 100 amp service.

You can easily have four 20 amp circuits on that 30 amp service.

You probably will bury 3/4" conduit (I would use plastic) 2' deep. That is code. I'm near certain that the same depth is required for direct burial cable, assuming you can find 10/3 direct burial cable.

Lord knows, assuming that you don't have much of a plan for the outlets at the coop, you could just run a 20 amp circuit from the main panel and not have a sub panel at all. That would require only 12 ga and then you can readily get 12/2 direct burial cable, and I'd put a GFI breaker in the panel to protect the circuit.

100 amp is massive over kill for your needs.

 

[vhcambrian]

<<You probably will bury 3/4" conduit (I would use plastic) 2' deep. That is code. I'm near certain that the same depth is required for direct burial cable, assuming you can find 10/3 direct burial cable.>>

It is actually only required to be buried 1' underground here. http://www.homedepot.com/p/Southwire-100-ft-10-3-Gray-Solid-UF-B-Wire-13059123/202316273

 

[vhcambrian]

I wondered about doing it this way too.

 

[Homeownerinburb]

<<You probably will bury 3/4" conduit (I would use plastic) 2' deep. That is code. I'm near certain that the same depth is required for direct burial cable, assuming you can find 10/3 direct burial cable.>>

It is actually only required to be buried 1' underground here. http://www.homedepot.com/p/Southwire-100-ft-10-3-Gray-Solid-UF-B-Wire-13059123/202316273

If you are burying only 1' deep buy a roll of electrical warning ribbon. It looks like the stuff painters use to cordon off wet paint, but it says "warning, buried electrical cable below" or some such. Fill the ditch half way then run the warning ribbon. You can get it at electrical wholesalers.

How far is the coop from the panel? If it is much more than 80 feet, that product from home depot will not help you.

Glad you are considering a smaller panel. I am even more of a mind to say just run a single 20 amp circuit with a GFI at the panel. It will carry a few lights and have power to spare for an occasional power tool. What else do you think you would run on such a circuit?

Simpler and cheaper are good assuming they are adequate.

 

[Reach4]

am even more of a mind to say just run a single 20 amp circuit with a GFI at the panel. It will carry a few lights and have power to spare for an occasional power tool. What else do you think you would run on such a circuit?

Heater for cold snap. Potential outlet for welder or electric vehicle charger? Outlet for big pressure washer?

 

[WorthFlorida]

http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

2011 NEC buried cable depth requirements.

 

[vhcambrian]

If you are burying only 1' deep buy a roll of electrical warning ribbon. It looks like the stuff painters use to cordon off wet paint, but it says "warning, buried electrical cable below" or some such. Fill the ditch half way then run the warning ribbon. You can get it at electrical wholesalers.

How far is the coop from the panel? If it is much more than 80 feet, that product from home depot will not help you.

Glad you are considering a smaller panel. I am even more of a mind to say just run a single 20 amp circuit with a GFI at the panel. It will carry a few lights and have power to spare for an occasional power tool. What else do you think you would run on such a circuit?

Simpler and cheaper are good assuming they are adequate.

I haven't measured but it's less then 100 feet from the main pole. Maybe an occasional power tool but not much else. I have a 30-amp plug at the pole and when the power is re-ran to the shop I'll have minimum 50-amp (old house burned down, all wires need to be re-ran to out buildings)

 

[vhcambrian]

http://www.xwalk.com/images/Table_300.5-Min_Cover_Reqts.pdf

2011 NEC buried cable depth requirements.

I mis-spoke. The note from my electrician:

The trench needs to be 24in deep. You can use a direct burial rated wire
without conduit if you want and only put conduit up the side of the pole
and buildings to protect the wire. You would need the appropriate sized
breaker based on the wire size that you used for each feed. You do have
plenty of power out there to do whatever you would want.

 

[vhcambrian]

Heater for cold snap. Potential outlet for welder or electric vehicle charger? Outlet for big pressure washer?

Chicken coop... use heat lights and maybe a brooder. All that other stuff goes in the 2-car garage or the 24x36 shop

 

[Homeownerinburb]

Chicken coop... use heat lights and maybe a brooder. All that other stuff goes in the 2-car garage or the 24x36 shop

Possibly a 30amp service, but look at what you propose to use.

You do understand, don't you, that a 30 amp service gives you TWO legs each with 120 volt potential against the shared neutral, with a 30 amp capacity.

So if your load looks to be 24 amps plus 24 amps and no more (you should run each leg at no more than 80% of its rating) and you should understand that the two sides of the phase are distinct from each other, thus me specifying 24 amps per leg.

Look at what your load is going to be before you choose a service size. 100 amps is almost certainly twice what you need, if not three times. No point in paying for a lot more copper than you need.

 

[vhcambrian]

Possibly a 30amp service, but look at what you propose to use.

You do understand, don't you, that a 30 amp service gives you TWO legs each with 120 volt potential against the shared neutral, with a 30 amp capacity.

So if your load looks to be 24 amps plus 24 amps and no more (you should run each leg at no more than 80% of its rating) and you should understand that the two sides of the phase are distinct from each other, thus me specifying 24 amps per leg.

Look at what your load is going to be before you choose a service size. 100 amps is almost certainly twice what you need, if not three times. No point in paying for a lot more copper than you need.

I'm here to learn. That is why I asked

 

[Reach4]

Here is a small and seldom-discussed consideration: If you use 10 gauge wire, that has about 1 ohms per 100 ft. Not much, right?

If you figure 10 amps on average for 2 wires only, for 250 ft (allowing a round trip plus some extra wire for connections), the wire consumes 25 watts. At 24 hours per day that comes to 219.15 watt-hours per year. At 10 cents per WH, that is about $21.92 per year warming up the ground.

With #6 wire, you would divide that power loss by 4.

If you were drawing 10 amps through 1 leg of the 240 only, that same math would hold, because 2 wires are carrying 10 amps each. If you had 10 resistive amps through both hots exactly, the neutral would carry no current. If there is a mismatch, that could factor in, but for estimating you could disregard. You could do the calculation using only the current of the highest-current hot.

Now you probably will not average 10 amps. To the extent that your loads are only occasional, the less this would matter.

Hey, you said you were here to learn. ;-)

 

[vhcambrian]

LOL Made me go look at what I'm charged per watt... starts at .076 and goes up from there. So 10/3 or 6/3 UF? I would have went with 12/2.

 

[Homeownerinburb]

LOL Made me go look at what I'm charged per watt... starts at .076 and goes up from there. So 10/3 or 6/3 UF? I would have went with 12/2.

For a 30 amp service 6/3 would be overkill. I think 8/3 is a lot for 30amp, but what the hell.

Copper is not cheap. But you have less than 100 ft, so do as you will. If you do 8/3 you could install a 40 amp breaker in the main panel should you need that much more service going forward.

Oh, and don't fret the fact that you won't find a sub panel with a small master breaker. (and you DO need a main or master breaker on the sub panel)

Just get the smallest available. It is not a breaker but rather is a switch that allows you to shut off all the power to the sub panel with one motion of the hand.

 

[Reach4]

Oh, and don't fret the fact that you won't find a sub panel with a small master breaker. (and you DO need a main or master breaker on the sub panel)

I think you are mistaken on that. The sub panel would be fed with a breaker in the main panel.