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I am installing a new range. The existing breaker is 40 amp.

Can I connect the new range to the existing wires (4 wires) and 40 amp breaker with a new 50 amp (4 wire) appliance cord?

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  • 1
    Is new range calling for 40 amps or more? Think there are no 40 amp plugs/outlets so they use 50 amp connections. Can go bigger, but can;t go smaller(using 30 amp connections a no-no).
    – crip659
    Sep 19, 2021 at 21:57
  • Hello and welcome to Home Improvement DIY. Also, take the tour
    – P2000
    Sep 19, 2021 at 22:11
  • Yes,the new range says to use a new UL listed 40 amp power supply cord,(can only find 50 amp coard)8 gage copper wire,or 6 gage aluminum wire.
    – Robert
    Sep 20, 2021 at 0:03
  • Just to be certain, the new range calls for a 40A breaker, correct? If it requires a 50A breaker, you could do this, but you'll probably end up with a lot of nuisance trips because the oven is trying to draw more power in normal operation than the breaker will allow.
    – FreeMan
    Sep 20, 2021 at 13:05
  • It would be almost impossible for any range to trip a 40 amp breaker. They don't draw that much current. There are some models that have a cleaning function that runs both the upper and lower oven element but the controls lock out the range burners when in cleaning mode. There may be a few models requiring a 50 amp circuit but if you have #8 wire, you would not be able to up the breaker to 50, you'd have to run a new circuit.
    – DrSparks
    Sep 22, 2021 at 1:55

2 Answers 2

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Yes. 50 amp range plugs and cords can be served by a 40 or 50 amp circuit.

If you're doing this yourself, you need to make sure you do the grounding right.

When you buy an electric range, there is either a strip of copper (usually the case) or length of wire bonding the neutral terminal to the chassis of the range. They come setup like this by default for people that still have 3 prong range outlets. If you have a three prong outlet and cord you need to leave that jumper in place. SUPER IMPORTANT.

If you have a 4 prong outlet and cord then you'll remove that jumper and attach the ground wire from the 4th prong to the ground terminal.

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A 50A receptacle/plug is the proper configuration to use with a 40A range and 40A range cord.

Pay special attention to the instructions that come with your range, they are part of the UL/CSA/ETL Listing. If the instructions specify a 50A breaker then you need a 50A breaker and wire to feed to it.

You may have a 40A breaker because a previous range specified a 40A breaker, but it is still possible that 50A wire was installed but a breaker was installed to match the range. I have never installed 40A wire for a range circuit.

Also the instructions may specify a minimum 40A cord or a 50A cord. They both use a NEMA 14-50 plug, but the 40A cord is only #10 awg wire, and is not Listed for a 50A range.

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  • There are few electric ranges on the market today that require a 50 amp circuit. I've never seen one. But a good point nonetheless.
    – DrSparks
    Sep 21, 2021 at 2:21

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