"major domo" wrote in message
...
I hired an electrician to come out and give a consult since I wrote the
questions.
He suggested option 1 at first (200A inside panel for heater and addition,
60' away from outside disconnect)
After he left, I checked the ampacity of the wire needed to feed option 1
and was told I'd need 4/0 feeder wire (at $7.50 a foot!) to carry
potentially 200amps.
Yes, 4/0 for aluminum, 2/0 for copper. And you must have a 4th equipment
grounding wire that is #4 aluminum or #6 copper. Big ugly feeder.
After reading your analysis and calling the electrician back, he said I
could optionally run 2 wires (one dedicated to inside heater, one to a
100amp panel) instead of 1 wire to do both.
That way I could run 4/3 copper 60' through the attic directly to the
heater (heater only) and 2/3 copper 60' through the attic to a 100amp
panel
for the addition (lights, sockets, stove, dryer, sewerage pump) (instead
of
a 200amp panel as per option 1), and have an outside breaker for each
seperate circuit (total of 4 circuits - old inside panel, new inside
panel,
central air heater, outside compressor).
It intuitively seems to be a better solution to distribute the load over 2
wires instead of 1.
Its actually better cost wise for one large feeder. Safety wise it shouldn't
matter as you'll protect the wires with the proper size breaker.
I rechecked my old inside main, and there is indeed a 100amp single throw
double breaker for the stove. At least when I throw it, the stove is off,
but other lights are on. The stove consists of a separate oven and
rangetop.
Have no idea why the original homeowners installed a 100amp breaker, but
it's there. I'm guessing the wire coming from it is a #6.
Wow. I'd definitely fix that when you change your power. I've never seen a
range that would be allowed to be connected to a 100A circuit. Probably
would be wise to double check all wire sizes and the breakers protecting
them.
BTW, the new central air and electric heater is a Goodman 4 ton 13 SEER
conventional unit (not a heat pump)
According to option 2 (which is what I'm tending towards now), the heater
will have it's own dedicated circuit from the outside meter base and
breaker.
Should I also have an second inside breaker/disconnect for the heater at
the
heater location (which is right above the new panel, in the new attic)?
The heater must have a disconnect within sight of the heater. If your main
panel or feeder disconnect is within sight of the heater, then you're done.
If not, you'll need a disconnect box (but it doesn't have to have a fuse or
breaker). Same rules for the outside A/C.
I appreciate your mention of separating the ground and neutral busses on
the
subpanel.
I don't know if the exisiting inside panel is able to be ground and
netural
separated. I do know that most of the wires going through the exisiting
structure do not have a ground wire. It is also good to know that a
subpanel
can have a main breaker (that was a hard one to find an answer to). Home
Repo suggested that a subpanel without a main breaker (main lug?) had to
be
used if the distance was 10 feet.
I want to be NEC-compliant and am very interested in doing it as properly
as
I can (and hoping to leave the existing inside panel untouched, minus
transferring some of the existing panel's load - stove, dryer, sewerage
pump - to the new panel)
May want to visit here if you have more questions:
http://www.selfhelpforums.com/forums...974ba858930386
db5be7e2574a3e83
--
Mark
Kent, WA