I want to wire a new Jenn Air Radiant downdraft cooktop. The wire from
the breaker only has three wires (Black,White, and Copper). I checked
the Black and White which were both "hot'. The directions say I need a
3 wire 120/240volt circuit). The cooktop has three wires in the
connection box - balck, red, and white ( No copper). Do I connect the
Black and Red wires from the cooktop to the balck and white "hot" wires
form the breaker.? What do do with the white from the cooktop and the
copper from the breaker? Thanks
You don't have what the manufacturer requires. You need a three conductor
with ground to feed it. The metal flex on the cooktop will be grounded by
the bare wire in the cable. The neutral and two hots get connected color for
But is it acceptable to code; presumably there is a jumper to connect the
frame to the neutral.
On a dryer it would be fine, but they plug in. Is is also fine on
permanently wired machines, or is that considered new work?
Thanks for the information. I just hooked it up so the two hot wires
(black and white) from the service are connected to the black and red
wires coming from the cooktop. I then connected the copper wire from
the service to the white wire from the cooktop. All seems to work fine.
Should I jump from the copper/white wire connection to a screw on the
metal frame box? It mayl be a while (maybe several weeks) before an
electrician can come out if necessary. Is there a problem with this
setup for a while? I think my previous cooktop had a similar
arrangement where the common and ground where connected, although that
top didn't have a fan. Thanks again for any advice.
It will work, and in certain circumstances it's legal, but doesn't meet
current code. In your case, the manufacturer specifically calls for a
120/240 volt three wire circuit, which you don't have. My guess is that this
cooktop pulls more current through the neutral than the manufacturer wants
to go through a shared neutral-ground.
Look at page 3 of your installation manual under the heading "Electrical
wiring information". If it indicates that the neutral is bonded to the
frame, you can use the existing wiring provided the cable is large enough to
carry the amperage of the unit
Thanks RBM> The instructions do indeed say the nuetral is grounded to
the frame. Does that mean I'm OK with the existing wires and it OK
that I have the bare copper from the service connected to the white
neutral from the Jenn Air. Is this OK for a permanent setup or do I
still need to have a new line run. It would be nice to not have to
bring the electrician out. Thanks again for all your time.
RBM (remove this) wrote:
Yes, that's what I mean. Provided the ampacity of the line is large enough
for the amperage draw of the new cooktop. The NEC requires new installations
to have both neutral and ground conductors, but does allow the use of an
existing three conductor feeder, and since the manufactures does not
specifically require separate neutral and ground, you're good to go
240V wiring is supposed to have black and red. I suppose that
electrician used what he had. It's that way in my house too. Just make
sure the wires are big enough. If you want to be more correct, you
could put a bit of red tape around that wire.
[But need to be opposite phases (240V [not 0V] between them).
Connect the white wire from the cooktop to the bare wire. Make sure
ground is connected to neutral on the cooktop. This'll work, but there
may be some rule about not using a bare wire as a current-carrying
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