Twin sub panel mess

[brad d]

i have two 200 amp panels in my house and can only take 100 amps from each.. so i guess i will do two 100 amp sub panels.. This is my first big wiring job and just learning.. .any tips before i mount up the panels? or do i need two?

one 6-2 TIG welder
one 6-2 compressor
one 6-2 boiler
three 8-2 MIG and band saw
two 10-2 lifts two spots
three 12-2 20amp plugs each wall has its own breaker
one 14-2 T8 lights 16 4' fixtures
one 14-2 garage door openers/ front plugs
one 14-2 two fans
one 14-2 roof plugs
one 14-2 out side lights
one 14-2 welding exhaust fan

here is the wall im installing the sub panels on

http://i44.photobucket.com/albums/f43/leyanh/Shop6/oakhammock023.jpg

and a shot of the wire from above

http://i44.photobucket.com/albums/f43/leyanh/Shop6/oakhammock024.jpg

[sberry]

You cannot feed a detached garage with 2 sets of feeders, you are going to need a separate service for 200A service. You can feed 125A from one of the panels though. I can tell you from experience (depending on tig machine) that a small garage will run from 100A service.

[brad d]

you cant run two lines?? to two sub panels?? from two panels?

the tig is 50 amps
the boiler is 50
and the compressor is 40...

im in canada and im new to this :) im sure our codes are close

[Junkman]

You cannot feed a detached garage with 2 sets of feeders, you are going to need a separate service for 200A service. You can feed 125A from one of the panels though. I can tell you from experience (depending on tig machine) that a small garage will run from 100A service.

you cant run two lines?? to two sub panels?? from two panels?

the tig is 50 amps
the boiler is 50
and the compressor is 40...

im in canada and im new to this :) im sure our codes are close

DISCLAIMER:
It is a full moon, and I am tired, and it a particularly bad mood, so I will ask the difficult question...

What part of "You cannot feed a detached garage with 2 sets of feeders, you are going to need a separate service for 200A service." didn't you understand.
Now, if you want to have two separate services, that can be done, if you separate the garage into two separate and distinct units. Just think of it as being the same as a two family home. The one constant is that you will have to pay for two separate meters if you are hell bent on having two panels, and they can not be sub panels... :lol_hitti

PS...... my apologies if I offended you in any way.. The full moon made me do it.... :thumbup:

[Charles (in GA)]

Need to look at the actual current draw on these items. Compressor for example. My 7.5 hp (real, running hp) draws about 33 amps if I recall. You don't say what you have, but I'll bet its no more than mine, and probably less.

The boiler is (under US NEC) considered a continuous load and as such should not exceed 80% of breaker capacity. So if you are using a 50 amp breaker your boiler should not draw more than 40 amps thru it. Need to look at actual current draw on the specs of the unit.

Your other devices probably won't be drawing much current.

Charles

[brad d]

humm..... i if it cant be done than i need to think of a new plan...

here is my house panels, i just wanted to run two 100 amp panels, one running off of each 200amp panel in the house.. the house is 400 amps...

http://i44.photobucket.com/albums/f43/leyanh/Shop6/oakhammock.jpg

[brad d]

Need to look at the actual current draw on these items. Compressor for example. My 7.5 hp (real, running hp) draws about 33 amps if I recall. You don't say what you have, but I'll bet its no more than mine, and probably less.

The boiler is (under US NEC) considered a continuous load and as such should not exceed 80% of breaker capacity. So if you are using a 50 amp breaker your boiler should not draw more than 40 amps thru it. Need to look at actual current draw on the specs of the unit.

Your other devices probably won't be drawing much current.

Charles

dont have a compressor yet but i was looking at a IR 7.5 HP, and the boiler says its a 50amp but requires a 70amp breaker..

I kinda think im going to need more than 100amps

[Junkman]

Does your home have 2 separate meters, one for each electrical panel, or is it one meter, 400 amps that is split into the two panels? It is rare to see a home with 400 amps, unless it is an all electric home, including heat... :headscrat

I have a suspicion that what you have is a 400 amp service with one meter, and they have split the two legs of the service into the two panels. The only other thing that comes to mind is if you have a 3 phase service, but that throws more into the equation than I care to think about this evenign...

[brad d]

yep 400 amps one meter, all electric home (hydro dam cheap power up here, i have gas too) its 400 amps on a bus bar then two lines to the 200 amp panels

[hidollartoys]

I was wondering why you could not feed two seperate subpanels from two seperate main panels? Is there a NEC code that this violates? Seems no different that feeding two different buildings from two different mains. I am unaware of a code that limits the number of subs vs mains. Please help with Nec code # Thanks.

[PAToyota]

Any chance you could consolidate the two house panels into one so that you can then run the other out to the garage and end up with one 200 amp panel in the house and one in the shop?

That's how mine is set up - one C320 service coming into the meter and then split to two 200 amp panels with one in the house and one in the shop.

[Aceman]

I was wondering why you could not feed two seperate subpanels from two seperate main panels? Is there a NEC code that this violates? Seems no different that feeding two different buildings from two different mains. I am unaware of a code that limits the number of subs vs mains. Please help with Nec code # Thanks.

You can't hit a separate building with two feeders unless you can meet the special conditions, which he doesn't.

2008 NEC 225.30

Brad, I think your best bet is to look into a seperate service/meter for your garage to get the 200 amp capacity.

[Junkman]

Up the house service to 600 amps, and put the third panel in the garage? That might be less expensive. Do they have a meter charge or do they only charge for the power you consume? In CT, I have a meter charge just for the privilege of them being able to bill me for what I use. I think it is about |$18 a month just for the meter.

[brad d]

fawk, i will check the local codes.. I upgraded to 400amps in the first place so I could do this.

[sberry]

I have 400 too but one of the 200's have a main lug feed thru. This is made just for this type of application. But, as was said before you can get 125A breaker for some panels. Usually the need for ampacity is over rated for home shops, have a bud that has a mechanic shop, air comp, even small 240V air cond, with all the lights has never,,, never,,, tripped the 60 feeding it. We have 100A wire and could change out the breaker if needed but it has never been an issue, even did a bit of welding from it on occasion.
I believe Aceman is a master (others here too but I am not real familiar with this site) but he could likely confirm the real power demands, they just are not as great as one might think. Only thing that is greedy is old welding machines like those 300A tig units, 700# monsters, I have one and even run it from a 60, tripped it once really smoking continuous on heavy aluminum project.

[PAToyota]

fawk, i will check the local codes.. I upgraded to 400amps in the first place so I could do this.

You upgraded to 400 and they split the house into two panels? If you upgraded the house from 200 to 400, they should have just left the 200 panel as it was in the house and ran the "other" 200 to the garage.

[rickairmedic]

yep 400 amps one meter, all electric home (hydro dam cheap power up here, i have gas too) its 400 amps on a bus bar then two lines to the 200 amp panels



Why couldnt you just pull off of the buss bar and feed one 200 amp panel in the shop straight from the buss that would make the most sence to me .


Rick

[brad d]

Yeah thats just the way the guy did it.. I dont know what he was thinking...

Then again I have two 25KW heaters and they run a 150amp breaker each.. on each 200amp panel

[brad d]

Why couldnt you just pull off of the buss bar and feed one 200 amp panel in the shop straight from the buss that would make the most sence to me .


Rick

i would love to do that but they will not let me.. cant have 3 2ooamp brakers off of one 400amp main line

[brad d]

So just to clear things up.. I called Hydro today (where we buy the power from).. and I can run two lines to the shop.. because its off of my house.. you cant run two lines right from the pole.. so cant to two service lines but you can sent two feed lines from your own service.

[rickairmedic]

Well tere ya go problem solved although I would still check with you local code enforcement office before I did anything that ended up having to be undone .

Rick

[brad d]

Hydro is the local code

http://www.hydro.mb.ca/customer_services/permits_and_inspections/electrical/inspections.shtml