(Electrically Connecting) installing a cook top

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Old 02-01-10, 10:32 AM
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(Electrically Connecting) installing a cook top

Kitchen 220 line has:

red wire
black wire
white wire

Cooktop has: rew wire, black wire and bare copper wire.

I connected red to red, black to black and white to copper.

Seems like no power to cooktop. Should I connect the white house wire
to the red or black wire on the cooktop? If I do this, should I cap the
bare copper wire from the cooktop or connect this wire to the junction box?

Thanks!

Mark
 
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Old 02-01-10, 11:12 AM
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You should connect black to black, red to red, white to white, and connect the green to the white (bonding jumper) at the cooktop. The cooktop should describe this process in the instructions under "three-wire circuit" installation.
 
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Old 02-01-10, 11:24 AM
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cooktop only has red, black and bare copper wires

Ben,

Many thank for the reply. The cooktop only has a red wire, a black wire and a bare copper wire. It doesn't have a white or green wire. There is no bonding jumper on the cooktop.

So, I'm not sure what to do with the white wire from the house
220 line with respect to connecting to the cooktop.

Thanks!
 
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Old 02-01-10, 11:34 AM
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Oh sorry, I missed that. Your original wiring should have worked fine unless something is wired incorrectly at the breaker. Also, it's a little sketchy to use the white wire as a ground in terms of code but there's really no harm that can come of it in this case.

Have you checked the wiring at the breaker? If you have a voltage tester, your house circuit should read 120V from black to white, 120V from red to white, and 240V from black to red.
 
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Old 02-01-10, 12:58 PM
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cooktop still not working

Thanks again Ben. I'm starting to think that the new cooktop is not working. I wired red to red, black to black and white from house to ground (bare copper) wire from cooktop. I'll check the
house wiring voltage as you suggested. The previous cooktop
had black, red, white and green wires. That cooktop
was wired red to red, black to black and then the white and green wire on the cooktop was wired to the white house 220 wire.

So, it seems like the new cook top wired red to red, black to black and white to copper (bare) should work, unless there
is something funny at the breaker.

Thanks again, Mark.
 
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Old 02-01-10, 01:52 PM
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I agree that if the previous cooktop worked as described, then the new unit may be defective. Perhaps the unit is shipped in a "safe" configuration? Maybe you need to remove a lockout tab or some type of packaging material? Occasionally you will see something like that in the instruction manual.
 
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Old 02-01-10, 02:53 PM
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So, it seems like the new cook top wired red to red, black to black and white to copper (bare) should work, unless there
is something funny at the breaker.
Is this cable or conduit?

Pros since you do not have a combined neutral ground can a white wire be used as a ground?

Bures000, sorry for going off track of your main problem but just curious if a white wire #6 or smaller can be used as a straight ground when no neutral is required for the device? Inefect you have a 240v device not a 120/240 so should 240v device rules apply rathen usual stove rules?
 
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Old 02-01-10, 04:07 PM
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house 240 line is a cable

Ibpooks and Ray2047, thanks for all the input. The house 240 line is a cable, not a conduit. It is a thick cable, outside is
black insulation. Inside the cable are three untwisted copper
wires of the same thickness, one red, one black and one white.

I'll check to see if the cooktop was shipped in a safe mode, but the manual does not mention this. I called the manufacturer today and they did not mention anything about this. They refused to answer questions about wiring, and how to match my house wiring to their product's wiring (very disappointing).

Sure seems like the way I wired it should work. Do you think
I should connect the white house wire to the red or black wire of the cooktop? I'm wondering if the white house 240 wire is 'neutral' and if it needs to be connected to something other than ground to complete the circuit--not sure if this makes sense.

Thanks,

Mark
 
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Old 02-01-10, 06:27 PM
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If you give us the make and mode numberl someone may be able to find an on line manual.
 
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Old 02-01-10, 06:52 PM
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cooktop make and model

The cooktop is a Bosch, model number NET8054UC.
The installation instructions have very little about the
connection. Says it needs a 3 line 240v power source,
red to red, black to black and bare copper wire to ground.

Thanks,

Mark
 
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Old 02-01-10, 07:20 PM
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Originally Posted by bures000 View Post
Do you think I should connect the white house wire to the red or black wire of the cooktop?
Definitely not; that might wreck it.

I think your next step is to inspect the wiring at the breaker panel. The black and red conductors should go to the two poles on the breaker and the white wire should go to the ground/neutral bar.

The next step would be to test the voltage with a multimeter. Set the meter to the 250V scale (or AC volts if autoscaling meter) and carefully test from each wire to each other wire.
 
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Old 02-02-10, 03:48 AM
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new cooktop has no fan

Thanks for the reply. I'm not sure how to get the breakers out of the box to take a look.

Here's a new thought. The old cooktop had a fan and I've read that on such appliances, the third line in the 240 supply is to help run the fan (so the white wire is in the house 240 line to run the fan). The new cooktop does not have a fan,
so I'm thinking for the new cooktop, red to red, black to black. Then I would dead end (cap) the white wire on the house 240 line. Finally, I would connect the bare copper (ground) wire from the new cooktop to the junction box for ground. Think this is OK?

Thanks,

Mark
 
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Old 02-02-10, 08:42 AM
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Thanks for the reply. I'm not sure how to get the breakers out of the box to take a look.
You don't actually need to remove the breakers, just remove the cover from the panel box. Be careful though as there are live parts inside even when the main breaker is off. If you have never done this before, I recommend enlisting the help of someone who has.

You can test the voltages at the cooktop location without opening the panel box.

Originally Posted by bures000 View Post
Finally, I would connect the bare copper (ground) wire from the new cooktop to the junction box for ground. Think this is OK?
That would be the correct method if you could verify that the junction box is grounded. It is probably not grounded as there was an exception in the code prior to 1996 that allowed ranges to be installed without a bare ground wire. If your home is older than that, you probably do not have a separate bare ground. It may be okay to re-identify your white wire as a ground in this case, but I'd like to see that the new cooktop is functional before messing with the house wiring.
 
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