I recently bought a Coleman Powermate Genny. It's 7000 watts, 8750
surge. While I'd love to backfeed my main panel for convience reasons,
I do realize it's illegal and unsafe. I'm considering a double pole 200
amp cutoff switch before the meter. (The main line is buried, comes up
to the meter and exits behind the meter to the main panel inside the
house). The main panel is a Cutler-Hammer 200 amp box. I don't see
where an interlock switch(at the main breaker) is available for my box.
Would a double pole cutoff switch make it safe to backfeed? I have a
120/240 30amp plug on the genny and already have an existing 50amp
socket on the wall for my compressor. Can I backfeed the 30amp line
thru the 50amp socket?
If backfeeding can't be accomplished, I'd consider a manual transfer
switch if I could find the right switch for my application. Most are up
to 7500 watts but I don't know if that will be enough with the surge
capability of my genny.
To comply with the US National Electric Code the connection arrangement
for your generator must be immune from human error. That means it must
be impossible to connect the generator to the public power lines even by
accident. Since it is physically possible to connect the generator to
the house with that double pole switch closed it is unlawful to connect
it that way. Additionally double male plugs are known as suicide cords
for a reason. One mistake means that you or a loved one could die. Do
it right or don't do it. The least expensive way to connect a generator
to the entire house would be to install a new SquareD feed through panel
ahead of your existing panel and install the SquareD interlock kit in
it. The cost of the equipment will be Two Hundred Fifty dollars ($250).
You would have to rearrange your existing panel to separate the
neutrals and Equipment Grounding Conductors (EGCs) onto separate buss
bars and isolate the neutral buss from ground. That new panel can be
tied in anywhere between the meter and the existing panel but if you use
an exterior panel you gain a place to supply outdoor equipment, branch
circuits, and feeders. The equipment could include well pumps, air
conditioners, pool equipment, jacuzzis, or fish ponds. The branch
circuits and feeders would be those serving separate buildings or the
loads I just listed. A two hundred ampere transfer switch, on the other
hand, would not give you any of those advantages and would cost $340 for
the indoor version of just the switch itself.
"This alternating current stuff is just a fad. It is much too dangerous
for general use." Thomas Alva Edison