adding a second panel in pole barn


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Old 05-19-08, 06:36 PM
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adding a second panel in pole barn

I live in MI and had a new home built in '03 and have at least a 300amp service coming into the home - I forget the exact amount perhaps 320? Anyhow the main panel uses approx 120amps. I want to add a second panel in my pole barn. The barn is at least 120ft away from the main service to the home. I'd like to run at least a 100amp service to the barn - more if required see below.

Things I'd like to power in the barn:

Garage Door opener (probably 3/4 to 1hp for a 16 x 10 door)
Exterior florescent floods
Interior lights / fixtures (qty. 20) again using florescent spirals
Approx 15 to 20 general purpose outlets (for basic hand tools etc nothing thats a real power hog)
6 ceiling fans w/o lights
A 220v dual stage 80gal air compressor
Future use (2 post automotive lift 220v)

My main concerns are - have I provisioned enough service (amp wise) and what type of monster wire am I going to need to make this huge distance?

I expect it would very rare to be using the auto lift the same time the compressor kicks on - but its always a possibility. I also was hoping to leave enough amperage for a future pool installation (filter / pump only).

Thanks!
 
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Old 05-19-08, 07:04 PM
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well, 100 amps will probably do it. but i would overbuild it to 200 amps. Sounds to me like you want to do some expanding, so why not. I wish i knew what your service looks like so i could suggest the right route to take, but i would suggest not feeding it from your house panel. An ideal situation would be if you had your own ct metered transformer, and to just come right off the transformer. But like i said, if i saw it maybe feeding out of your home is the better way.

If your home is using 120 amps on average, it'll be higher at times when things start up.

If you want to go with a 200 amp service, you could use 4/0 aluminum usc wire to go underground. Or 1/0 usc for a 100 amp service. Its not to expensive, definetly still cheaper than copper .
 
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Old 05-19-08, 07:30 PM
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[QUOTE=BIGJPAYNE;1367741]I live in MI and had a new home built in '03 and have at least a 300amp service coming into the home - I forget the exact amount perhaps 320? Anyhow the main panel uses approx 120amps.[\QUOTE]

300 amp is kind of an odd size. No way it would be 320 amps (way too odd). Look on your main breaker or switch and what it is printed on the handle or you should see some kind of label on the outside. Do you have a CT cabinet? Is would be a large box about 3' X 3' on the outside of your house. Unless you have a very large home or are running electric heat, I would bet to have 200 amps.

P.s. How do you know the main panel is using 120 amps? Did you check with a clamp on meter?
 
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Old 05-19-08, 08:01 PM
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[QUOTE=Tolyn Ironhand;1367768]
Originally Posted by BIGJPAYNE
I live in MI and had a new home built in '03 and have at least a 300amp service coming into the home - I forget the exact amount perhaps 320? Anyhow the main panel uses approx 120amps.[\QUOTE]

300 amp is kind of an odd size. No way it would be 320 amps (way too odd). Look on your main breaker or switch and what it is printed on the handle or you should see some kind of label on the outside. Do you have a CT cabinet? Is would be a large box about 3' X 3' on the outside of your house. Unless you have a very large home or are running electric heat, I would bet to have 200 amps.

P.s. How do you know the main panel is using 120 amps? Did you check with a clamp on meter?
sorry tolyn but a 320 is very common. It is often referred to as a resi 400 amp service.
 
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Old 05-19-08, 08:14 PM
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Tolyn.,, The 320 service will have few combation of load centres

• 2X200 panels
• single 400 amp panel
• 1- 200 amp panel and 1 -100 amp panel [ not very often but it do show up ]

above list is most common arrangements for the 320 system.

Merci,Marc
 
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Old 05-20-08, 08:07 AM
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You can feed your 100A subpanel with #2-2-2-6 USE-2 aluminum cable. Sometimes this is sold as 100A mobile home feeder cable. It can be direct buried 24" deep with conduit sleeves on the vertical risers into and out of the trench.

The subpanel will require isolated ground and neutral bars, and two 8' ground rods bonded with acorn clamps and #6 bare copper to the ground bar in the subpanel.
 
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Old 05-20-08, 04:26 PM
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Ah..So the 320 amp is the rating of the meter socket, not the main panel. I have not seen one before. Thanks for pointing this out.
 
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Old 05-21-08, 06:51 AM
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Wow thanks for all the replies. I'm on the road at the moment so I'll double check and get back to all of you who requested additional info.

Yes there is a dedicated transformer that DTE installed when service was implemented - it only feeds our home (underground from pole). I distinctfully remember them asking for the type of service (amp wise) and I chose the higher of the two options they gave me which was in the 300s somewhere. There is no 3' by 3' box / panel of sorts.

I'm not to keen of the idea of running from the pole with a second meter only because that would involve DTE again:

1) they did a hack job on my lawn the first time
2) they are NOT cheap for underground service leads

Thanks again - I'll update this post with further information regarding our panel / service by this weekend hopefully.

-J
 
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Old 05-21-08, 03:04 PM
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Originally Posted by Tolyn Ironhand
Ah..So the 320 amp is the rating of the meter socket, not the main panel. I have not seen one before. Thanks for pointing this out.
the service ampacity is not simply what the main breaker on A panel is. You can have up to 6 "main panels" and the total calulated load is what the service size needs to be.

I have had an 800 amp service that had 5 200 amp and 1 100 amp panels as the "main".
 
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Old 05-21-08, 05:20 PM
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i know you didn't like your previous contractor, but i would still suggest calling in another contrator, and then tell them exactly what you didn't like about your last contractor. If they are any good, they'll do a better job just to prove they are better.

We need to know, is your meter on the house or at the pole? I don't know this for a fact but i don't think they make 300+ amp inline meters which would mean you have to be ct metered. If you are, you shouldn't need another meter socket...

And if you're worried about someone tearing up your yard, don't pay them until they fix it, and tell them that. Take pictures and if they don't fix it when you want them to, hire a landscaper to come fix it, and then send them the bill. We have one home owner in town that built a huge house, they've been living in it for over 2 years now, and still hasn't paid their plumber for the whole job because they did shotty work and haven't fixed it.

gl
 
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Old 05-21-08, 06:46 PM
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Not a great pic but this is one of many 320 meter sockets avaialble. You can even get a 400 amp rated (continuous 400 amp) feed through style meter.

and I believe the reference to DTE is the POCO. I know in my area, the POCO is the only group (including their own subs) to install a service lateral or drop so there is no other contractor possible.

Also, in my area a second meter gets charged commercial rates.

If he has a 320 service I doubt he will need to upsize the service.
 
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Old 05-21-08, 07:23 PM
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Originally Posted by nap
the service ampacity is not simply what the main breaker on A panel is. You can have up to 6 "main panels" and the total calulated load is what the service size needs to be.

I have had an 800 amp service that had 5 200 amp and 1 100 amp panels as the "main".

Yes, I understand this. My point/question was more about the 320 amp. 320 amp is not a standard overcurrent device and it would be tough to get panels that would sum up to 320 amps. I now see the meter socket is what is rated at 320 amps (80% of 400) Would you still call this a 320 amp service, 400 amp service or two, 200 amp services? I guess I would call it two 200 amp services, just to be clear.

Nap - On your 800 amp instalation how were these main services fed? Was it a gutter with 800 amp rated wire and then each service was taped off of that?
 
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Old 05-21-08, 08:04 PM
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=Tolyn Ironhand;1368730]Yes, I understand this. My point/question was more about the 320 amp. 320 amp is not a standard overcurrent device and it would be tough to get panels that would sum up to 320 amps.
what they add up to is actually irrelevent. It is what the service is rated at (which is actually a POCO determination.

well, let me rephrase that.

The POCO provides a service that is rated for a max current. The HO installs equipment that matches that rating. It is a co-operative situation.

I now see the meter socket is what is rated at 320 amps (80% of 400) Would you still call this a 320 amp service, 400 amp service or two, 200 amp services? I guess I would call it two 200 amp services, just to be clear.
In my are it would be considered one of 2 things typically; a 320 service or a resi 400 amp service. It would never be 2- 200 amp services as that denotes multiple services, which this is not. It is only one service.

Nap - On your 800 amp instalation how were these main services fed? Was it a gutter with 800 amp rated wire and then each service was taped off of that?
6 sets of feeders from the pad mount transformer.

the reason it was an 800 amp service is because the transformer the POCO intalled was rated for an 800 amp service. It had little to do with the panels attached to it.
 
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Old 05-22-08, 07:15 AM
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Originally Posted by Tolyn Ironhand
Would you still call this a 320 amp service, 400 amp service or two, 200 amp services? I guess I would call it two 200 amp services, just to be clear.
I've always heard it called a "residential 400A".
 
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Old 05-29-08, 05:43 AM
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All right - sorry for the delay been quite busy. The "service" as described to me by DTE (the local power company) is 320 amp. I'm using 150 of that in one panel of the house. I really don't see requiring any additional circuits in the house for future use - we already over built a bit to accommodate.

Someone asked about the meter/service - additional electrical poles were installed by DTE from the road down the side of our property with our own dedicated transformer, then service runs underground to the house, which is where the meter resides.

So my new question is - should I just run another 150 to the barn similar to the house? I took another look and the distance is more like 120ft if that matters. I doubt I'll ever use that much in the barn itself but if we ever add a pool I'd like to run it from the barn vs. the house.

Also what type of conduit (if any) does this run from house to barn need to be in? I know you need conduit coming out of the ground - I'm talking IN the ground though. I also want to run some low voltage stuff as well (satellite, cat5, etc). I'm aware high and low voltage stuff shouldn't run directly with each other parallel...but can they be in the same trench if one is in conduit? Would it need to be metal or would plastic suffice?

Thanks for the info fellas.

-J
 

Last edited by BIGJPAYNE; 05-29-08 at 06:01 AM.
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Old 05-29-08, 08:20 AM
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Run PVC for both runs (low voltage in one and high in another) Same trench. Make sure to put in a over sized pipe (maybe 1"-1.25") for your low voltage in case you want to add anything later (Internet, Intercom, CCTV) Bury the power 18" down (to the top of the pipe) cover with 3" or so of dirt. Lay low voltage pipe on top. Since your making this trench you may also think about a gas line for heat. (unless your propane then you can just use another tank)

BTW - How do you know you are using 150 amps of your service? Are you measuring with a clamp on meter or just adding up the breakers?
 
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Old 05-29-08, 05:37 PM
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a pvc run from building to building is unnecessary. Simply use pvc to get outside and into the ground. Buy USC wire (underground service cable), its black, aluminum wire that can be directly buried. You'll need to bury it 24" deep, but if you're going a hundred feet, i doubt you're going to be shoveling it anyway.

You can run pvc the whole way if you want, but the fact of the matter is, you're not likely going to run copper feeders all the way over there, so you're left with aluminum, and you're only going to find aluminum wire in underground wire anyway. so pvc is kind of a waste of time/materials.

As far as low voltage, i would suggest buying direct burial cables also. You can buy underground coax, you can buy underground telephone wire (i.e heavy duty cat5). They both have thicker insulation and have a de-oxidizers in them. Fill your trench half full and through them in. Around here, the cable and phone companies put their wires in right with ours, i don't think thats quite right, but they say its ok.

gl
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Old 06-05-08, 07:24 AM
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Just thought I'd update this for anyone with the same question(s). Local contractor supply informed me 2/0 is most common for 150a service.

Side note - only reason I'm not keen on the direct bury low voltage - I still have several boxes of cable left over so I think buying conduit would be cheaper then a new box of direct bury.

Thanks again everyone for all the useful info!

-J
 
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Old 06-05-08, 03:39 PM
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Originally Posted by BIGJPAYNE

Side note - only reason I'm not keen on the direct bury low voltage - I still have several boxes of cable left over so I think buying conduit would be cheaper then a new box of direct bury.



-J

What type of wire you got there ?? It will make the diffrence there if you got indivual cables they have to be marked THHN/THWN to order to run underground in the conduit due wet location.

Merci,Marc
 
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Old 06-05-08, 06:46 PM
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if you have cable left over...that means you should be able to use that (in fact thats all the more reason to use it)...either way you'll have wire left over. have you had problems with your direct bury cable before? Keep in mind, buried pvc is not always waterproof.
 
 

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