My breaker panel is a Square D, Homeline, 30/30 type with a 200 amp supply.
All breaker spaces are in use. Being a 30/30 type I cannot replace some of
the existing breakers with two gang, 120 volt breakers. Is this correct?
I'm assuming I need to extend my existing breaker panel with a second small
panel. Should this be wired to the main feed or can it be wired to the buses
inside the existing panel? The second would be easier for me. There will be
five extra circuits, some twenty amp, some 15 amp. Do these five extra
circuits need to be divided among two phases or can I put them all on one
phase? An additional panel would be small and would have to be placed below
the existing panel. Is this a problem for inspection?
I appreciate all the help I can get.
If your existing breaker panel has a second set of lugs
on the main input for going to a second panel, I would use
these. Be sure to use the same wire size that goes from the
meter to the main panel to go from the main to the second panel.
It isn't far, and won't cost much. Probably something like 2/0 , if
memory serves, and carry the neutral and ground and both
sides of the line. Do not use a new ground rod for the second
panel, but put a BIG neutral, like #6 or bigger, between the two
Use both phases of the input and try to put about half of
the breakers in the new panel on one line and the other half
on the other. They will all work on one phase, but dividing them
is a better way to do it.....
Nope, you would then be overloading the service entrance. Without
upgrading the service you will have to go from the bus in the panel
downstream of the service disconnect.
Your panel may be able to accept a bus tap (be sure you understand the
"tap" rules) but you may end up having to move 2 circuits to the sub
and installing a 2 pole breaker to feed a MLO sub panel.
I agree with you.... I was assuming that the main disconnect would
disable the second set of lugs. I have seen panels where this is
standard.... Perhaps I should have been clearer.....
Thanks for pointing this out, tho I cannot conceive of any
manufacturer who would not have a disconnect prior to a
second take-off...... It would be a big liability issue if anyone
decided to use them.....
the breakers your thinking of are called "twins" 2 breakers on one pole
Best start with your utility company and find out if your even using close
to the 200 amps. (probably not) That means you could do some rearranging and
put in a sub panel for some added pole spaces.
Call a local licensed and bonded pro and have them come out and look at the
job. We are all just guessing with little information.
If you wire off of the main feeders from the meter your subpanel should have
a main shutoff. I'd wire the subpanel from a 2 pole breaker in the main
panel. Remove 2 existing circuits from the main panel and put them in the
subpanel. Your subpanel doesn't necessarily need to be small. I have a 30
space panel nearly filled (3 left) and I have 100 amp service. Subpanels are
surprisingly inexpensive. Get one with as many spaces as you can afford
that'll fit where you want it.
You'll need to buy an appropriately sized breaker for your main panel as
well as the proper size wire. Make sure the neutral isn't bonded to the case
in the subpanel and run a separate ground and (insulated) neutral from the
Many thanks to all. I put in a small sub panel via a nipple. Feed was from a
60 amp double breaker on the main panel. The sub panel has six spaces which
also accept twin breakers. I have installed four single breakers and two
twin breakers for a total of eight circuits. Everything works OK.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.