Mark Lloyd wrote:
On Fri, 12 Dec 2008 09:57:17 -0600, bud--
wrote:
wrote:
My gas furnace is hard wired to the main panel. In the event of an
extended power outage in winter, I'd like to have the option to run it
off my small Honda generator. The only real electrical draw is the
small 110V blower motor.
If we were in for an extended outage right now, I would probably just
jury-rig it with wire nuts and a sacrificed 12ga extension cord. I'd
like something a little more... sophisticated, something that is ready
on a moment's notice.
What if I:
1. Cut the existing hard line above the furnace and install a box with
an L5-20 twistlock socket.
2. Continue the hard line to the furnace from a second box adjacent to
the first.
3. Bug a short piece of 12-3 flexible cord to the hard line in the
second box.
4. Terminate the flexible cord with an L5-20 twistlock plug.
Is this kosher with NEC?
Don't think so.
The suggestion I have seen is put a double pole double throw switch on
the H and N wires and switch them to a male socket to which you attach
an extension cord when necessary.
Any reason it needs to be that complicated? No need for a switch at
all, just put a regular plug on the wires going to the furnace and
move it to either a regular receptacle or an extension cords.
A switch and an "inlet" isn't much more complicated.
The NEC limits the use of cords to connect equipment (422.16 is
relevant). Cord and plug connection is permitted for maintenance and
repair or frequent interchange. (Specifically alloweded are garbage
disposers, range hoods and wall mounted ovens.) If boilers and furnaces
were allowed to be cord and plug connected you would probably have
receptacles provided, and boilers and furnaces would come with cords the
HVAC installer would plug-in. (Would there be an electrical inspection?
If there was no furnace circuit outlet would someone connect to a
general use outlet with an extension cord?) IMHO hard wired is more
reliable for an essential function.
As I said in another post "aside from the code, the plan sounds
practical and safe."
--
bud--