Replacing cooktop, need to increase wire/breaker size

[jumpstart]

I need to replace the existing 40 amp breaker with a 50 amp per the instructions with the new cooktop. The also requires increasing the wire size from 8 awh to 6 awg.

The existing wire is 3 conductor. I found the white neutral is just capped in the junction box where the appliance whip is connected. Only the black and red ( conductors) and ground is needed. With the new 6 awg, can't I just use 6/2 wire?

 

[BillK]

Only the black and red ( conductors) and ground is needed. With the new 6 awg, can't I just use 6/2 wire?

I think you actually need the neutral for the 120v control circuits. The old setup was probably using the ground for neutral too. I was under the impression that all new and upgraded installations had to be 4 wire. Hopefully somebody else will verify that.

 

[sparky 1971]

6/2 should be fine, but it depends on whether or not the new cooktop needs a neutral, I don't recall ever seeing one that did but it's been awhile. How many wires are in the new cooktops whip?

 

[wyliesdiesels]

Doubt a cooktop needs a neutral but better to verify first

 

[jumpstart]

6/2 should be fine, but it depends on whether or not the new cooktop needs a neutral, I don't recall ever seeing one that did but it's been awhile. How many wires are in the new cooktops whip?

It just has 2 wires and a ground.

 

[tfi racing]

I'm willing to bet that you can swap the existing 40A breaker with a 30A, use the existing conductors and crank all the burners to full heat and still not trip the 30A breaker...

 

[sparky 1971]

It just has 2 wires and a ground.

Then 6/2 will work

 

[alfredeneuman]

I'm willing to bet that you can swap the existing 40A breaker with a 30A, use the existing conductors and crank all the burners to full heat and still not trip the 30A breaker...

I need to replace the existing 40 amp breaker with a 50 amp per the instructions

It's a Code violation not to follow the instructions (110.3 B)

 

[Metal-Marc]

I'm willing to bet that you can swap the existing 40A breaker with a 30A, use the existing conductors and crank all the burners to full heat and still not trip the 30A breaker...

I'm willing to bet that you're wrong.

 

[Milton Shaw]

Most cooktops years ago had 4 standard wattage burners and even 20 years ago the pigtails on GE were wired black, red, white tied to bare or green. Now cooktops may have 5 or more higher wattage burners so that is why they have the amp upgrade. I would suggest the 6/3 with G so that if that new one fails early you can meet wiring requirements for it's replacement. Appliances and everything else are not lasting like they did even 15 years ago. Its much easier to upgrade once than have to do it again 5-10 years down the road.

 

[Bert_]

In my own house I would wire it to the existing circuit and in the event it ever trips the breaker I would rewire. Good chance that never happens.

I've seen a couple of ranges wired with a 30 amp breaker and #10 wire. I asked the owners about it and they said it's never tripped.

I've measured amps on my own range and it will hit the upper 30s if you turn on all the burners and the oven. But once a couple burners or the oven warm up it's down in the 20s or even less.

 

[klassenl]

In my own house I would wire it to the existing circuit and in the event it ever trips the breaker I would rewire. Good chance that never happens.

I've seen a couple of ranges wired with a 30 amp breaker and #10 wire. I asked the owners about it and they said it's never tripped.

I've measured amps on my own range and it will hit the upper 30s if you turn on all the burners and the oven. But once a couple burners or the oven warm up it's down in the 20s or even less.

In my own house I would try in the existing wiring. There was a time not that long ago 2 pole 40a breakers were scarce so some stoves got a 2p 30. Haven't heard of any problems yet.

However. We could all be wrong and the new appliance will actually draw up to 45 or more amps.

 

[jumpstart]

In my own house I would try in the existing wiring. There was a time not that long ago 2 pole 40a breakers were scarce so some stoves got a 2p 30. Haven't heard of any problems yet.

However. We could all be wrong and the new appliance will actually draw up to 45 or more amps.

I'm going to rewire and use the 50amp per manual. Manual shows max draw at 45.6amp. Probably never use it with all burners on max, but pretty easy to access wiring in basement so I'll just do it and be done.

Thanks all for the advice.

 

[75gmck25]

You may want to run 6/3, just in case you later find an upgraded appliance you want to use in a future remodel. It's not that much more per foot, and you will be prewired for a future appliance that needs a neutral (usually because part of the appliance needs 120 volts).