stasha
New member
- Location
- Louisville, KY
Sorry to bother this forum with probably simple and basic questions, but the info on the internet appears conflicting, is overwhelming, and I do not trust my level of understanding.
BUT I WANT TO UNDERSTAND THINGS BETTER, especially since I am doing most work myself.
So, here goes...
DETAILS ABOUT ELECTRICAL STATUS OF THE HOUSE:
The house we got now has about 3500SF, with finished basement and attic.
It has a 200AMP main box with the usual AC, washer/dryer, Microwave, oven, three refrigerators, etc., plus 60Amp breaker feeding a subpanel in a detached garage (full of power tools, air compressor, etc).
All circuit breaker openings in the 200A box are occupied (with several 2-in-1-space breakers).
I ALSO recently installed a 100Amp subpanel to accommodate a 60a/220V swim spa, and I also moved several of the 2-in-1 breakers over to this subpanel to increase space in the 200A box for the 100A breaker whose line fed the new 100A subpanel.
(I somehow have to figure out how to attach pix of the two breaker boxes, showing the amps/breakers.)
Furthermore, NOW, I have almost completed the installation of a DIY ductless 18000 BTU heat pump (30A/220V) to air condition the finished attic.
...and I am concerned that I may be over-reaching the capacity of my 200A main box.
The sum of the amps of the circuit breakers in BOTH the 200A main and 100A subpanel each greatly exceed the 200A and 100A ratings of their respective boxes.
Comments, reactions, warnings, etc, are most definitely requested at this point.
HOWEVER, here are my basic questions:
1) How can I calculate whether the loads on my breaker boxes are maxxed out or even dangerously exceeded? In other words, should a 200A box with two subpanels (100A and 60A subpanels) be able to handle just about anything a household can throw at it?
2) In regards to powering my new ductless 30A/220V heat pump... can I just install a 30A/220V breaker in the 100A subpanel to feed the outside AC cutoff box? Would this overtax the 100A subpanel so that I should add yet another separate subpanel from which to feed the AC unit?
3) I am uncertain about whether I should use a fused or a non-fused outside box for the heat pump, since I plan on using a 30A/220V circuit breaker on the inside subpanel. Is this something that a city building code would prescribe, or is there a universal answer?
4) Also in regards to the outside box for the heat pump – since I would have a 30A/220V circuit breaker feeding it, CAN I USE A NON-FUSED but 60A outside box for the heat pump? They are much cheaper than the 30A boxes at Lowes, for some reason.
That’s it for the questions for now.
Appreciate any input.
Thanks.
BUT I WANT TO UNDERSTAND THINGS BETTER, especially since I am doing most work myself.
So, here goes...
DETAILS ABOUT ELECTRICAL STATUS OF THE HOUSE:
The house we got now has about 3500SF, with finished basement and attic.
It has a 200AMP main box with the usual AC, washer/dryer, Microwave, oven, three refrigerators, etc., plus 60Amp breaker feeding a subpanel in a detached garage (full of power tools, air compressor, etc).
All circuit breaker openings in the 200A box are occupied (with several 2-in-1-space breakers).
I ALSO recently installed a 100Amp subpanel to accommodate a 60a/220V swim spa, and I also moved several of the 2-in-1 breakers over to this subpanel to increase space in the 200A box for the 100A breaker whose line fed the new 100A subpanel.
(I somehow have to figure out how to attach pix of the two breaker boxes, showing the amps/breakers.)
Furthermore, NOW, I have almost completed the installation of a DIY ductless 18000 BTU heat pump (30A/220V) to air condition the finished attic.
...and I am concerned that I may be over-reaching the capacity of my 200A main box.
The sum of the amps of the circuit breakers in BOTH the 200A main and 100A subpanel each greatly exceed the 200A and 100A ratings of their respective boxes.
Comments, reactions, warnings, etc, are most definitely requested at this point.
HOWEVER, here are my basic questions:
1) How can I calculate whether the loads on my breaker boxes are maxxed out or even dangerously exceeded? In other words, should a 200A box with two subpanels (100A and 60A subpanels) be able to handle just about anything a household can throw at it?
2) In regards to powering my new ductless 30A/220V heat pump... can I just install a 30A/220V breaker in the 100A subpanel to feed the outside AC cutoff box? Would this overtax the 100A subpanel so that I should add yet another separate subpanel from which to feed the AC unit?
3) I am uncertain about whether I should use a fused or a non-fused outside box for the heat pump, since I plan on using a 30A/220V circuit breaker on the inside subpanel. Is this something that a city building code would prescribe, or is there a universal answer?
4) Also in regards to the outside box for the heat pump – since I would have a 30A/220V circuit breaker feeding it, CAN I USE A NON-FUSED but 60A outside box for the heat pump? They are much cheaper than the 30A boxes at Lowes, for some reason.
That’s it for the questions for now.
Appreciate any input.
Thanks.
