main panel question(s)
#1
03-10-13, 11:17 PM
Join Date: Mar 2013
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main panel question(s)
I have been doing renovations on my house for some time now and have come to the point where I will be needing electrical work. I have a couple of questions about main panel to subpanel wiring.
I have what looks to me, after doing a little research, 100 amp service coming into a main panel.
1. I am thinking about instaling a separate panel on each floor wired from the main panel in the basement, is this something that is common?
2. How close to the service entrance(meter) does the main panel need to be?
3. Can the subpanel be a 100amp subpanel and if it is what size wire will it be 40 feet away from the main panel?
Thanks guys for all postings
I have what looks to me, after doing a little research, 100 amp service coming into a main panel.
1. I am thinking about instaling a separate panel on each floor wired from the main panel in the basement, is this something that is common?
2. How close to the service entrance(meter) does the main panel need to be?
3. Can the subpanel be a 100amp subpanel and if it is what size wire will it be 40 feet away from the main panel?
Thanks guys for all postings
Last edited by Nashkat1; 03-11-13 at 01:50 PM. Reason: Remove formatting and duplicated text
#2
03-10-13, 11:57 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
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1. Not common in residential usage but not totally unheard of either.
2. The "main" (service) panel has no particular requirement regarding proximity to the meter. Remember that there is NO short circuit protection between the meter and the service panel in most cases. Because of this most AHJ's will only allow the shortest distance that is practicable between meter and panel to be run inside the house. You CAN get around this by installing a "disconnect" at the meter and then treating all subsequent panels as sub-panels.
3. Sub-panel ratings must be sized to the size of the supplying feeder circuit breaker rating or higher. If you have a 100 ampere disconnect (fuse or circuit breaker) at the meter then you may use any panel with a minimum rating of 100 amperes. You may use a panel of 125, 150 , 200 or higher amperage rating if you have some reason to do so but you will not get any more power from it. You may NOT use a 60 ampere or lower with a 100 ampere feeder.
The wire size for a 100 ampere circuit breaker is a minimum of #3 copper IF the terminations are listed for use at 75 degrees, C. Aluminum would be #1. The equipment grounding conductor could be as small as #8 copper or #6 aluminum.
2. The "main" (service) panel has no particular requirement regarding proximity to the meter. Remember that there is NO short circuit protection between the meter and the service panel in most cases. Because of this most AHJ's will only allow the shortest distance that is practicable between meter and panel to be run inside the house. You CAN get around this by installing a "disconnect" at the meter and then treating all subsequent panels as sub-panels.
3. Sub-panel ratings must be sized to the size of the supplying feeder circuit breaker rating or higher. If you have a 100 ampere disconnect (fuse or circuit breaker) at the meter then you may use any panel with a minimum rating of 100 amperes. You may use a panel of 125, 150 , 200 or higher amperage rating if you have some reason to do so but you will not get any more power from it. You may NOT use a 60 ampere or lower with a 100 ampere feeder.
The wire size for a 100 ampere circuit breaker is a minimum of #3 copper IF the terminations are listed for use at 75 degrees, C. Aluminum would be #1. The equipment grounding conductor could be as small as #8 copper or #6 aluminum.
#3
03-11-13, 02:05 PM
1. I am thinking about instaling a separate panel on each floor wired from the main panel in the basement, is this something that is common?
2. How close to the service entrance(meter) does the main panel need to be?
3. Can the subpanel be a 100amp subpanel...
#4
03-11-13, 06:50 PM
Unless you have a particularly large house, I would suggest you consider sticking to a single panel. It will likely mean only a bit more wire, and the downsides usually outweigh the upsides of being easier when you're doing the installation. Plus, in a properly wired house, breakers should rarely if ever trip, so walking all the way downstairs to the main panel shouldn't be a big deal.
Probably the biggest issue with installing one on each floor is finding the space to install it. You need the equivalent of a refrigerator box in front of the panel (36" deep, 30" left to right, and 6' high). You shouldn't be putting furniture in that space to keep it clear, and there are rules about putting them in closets. Also, most people don't want to see them.
Of course, nothing wrong code-wise with multiple sub panels... just something to consider.
Probably the biggest issue with installing one on each floor is finding the space to install it. You need the equivalent of a refrigerator box in front of the panel (36" deep, 30" left to right, and 6' high). You shouldn't be putting furniture in that space to keep it clear, and there are rules about putting them in closets. Also, most people don't want to see them.
Of course, nothing wrong code-wise with multiple sub panels... just something to consider.
