sub panel
- Thread starter laketime
- Start date
- Status
bradleyelectric
Senior Member
- Location
- forest hill, md
As long as the load served does not exceed the main breaker in the main panel you can have as many 200A panels as you can get your hands on.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Short answer is yes. You would need to perform a load calculation to determine if the existing 200 amp service is large enough.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
If the owner needs 200 amps of service at the garage then you will not have 200 amps to give him.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Just knowing it is a house implies the minimum required calculated loads, regardless of actual usage. That would preclude 200A being available for the garage from a 200A service for both.
Why? What do we know about the usage patterns at the house?
Why? What do we know about the usage patterns at the house?
Good topic for discussion, we find many jobs where the service was under size or over sized it appears doing a load calc is a strange thing to many EC's it is much easier to just guess and hope for the best.
"What do we know about the usage patterns at the house" is something we should be asking on every service we plan.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
No. My point is the actual usage is not the calculated load.
If the house load is not running, just how does the calculated load at the house limit the actual current drawn at the garage?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Al, come on. I am assuming that people live in the house and there will be some usage of power whether it be a refrig., ac, furnace or all of the above. My point, I thought, was obvious but not on this site. :roll:
If the calculated load at the garage is 200 amps then you could not legally give the garage 200 amps when there is only 200 amps at the house whether the house is not being used or not. You cannot decide when and how each space is used.
Because we do not base service equipment ratings on actual usage unless it is greater than the minimum required calculated loads. Sure there may be 200A available for the garage with all house loads deenergized, but that would be an undersized, non-compliant service per the NEC.
Additionally, a 200A service disconnecting means, installed to Code, only guarantees a 176A service without knowing service conductor size, type, and any adjustments to the ampacity.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
Look again at the OP. It's the customer that wants the 200 A panel in the garage. I doubt that there is much more than a "this feels good" involved in the request by the customer.
Laketime, what are some of the characteristics of this home / garage? Gas range, gas water heater, gas dryer ?
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
Al I never said that he could not put a 200 amp panel with a 200 amp main & the wire to boot. As long as the calculated load is less then 200 amps I see no problem. My point was if the guy really wanted 200 amps then he cannot get it this way. I doubt he really needs 200 amps in the shop.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
I totally agree. This type of request is almost always a vanity intallation.
al hildenbrand
Senior Member
- Location
- Minnesota
- Occupation
- Electrical Contractor, Electrical Consultant, Electrical Engineer
The thing I find amazing about 220.83 is how lenient the 40% part of it works out to be, especially in a modest home with a 200 Amp service and no electric heating.
laketime
Senior Member
I am not sure about any of the house loads. It was an employee at a business I do service work at that asked for me to check it out for him. I am thinking he wants 200 amps because "200 is more than 100 right?". I know he welds on the side. I will need to do a load calc on his house and then check out his equipment for the garage and see what he will get not what he wants.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
No but you can use a feed thru panel with 200 amp conductors.
- Status