Proper Breaker for Electric Range

[SAS]

The Samsung electric range in our new house says in the installation manual that, "A range cord rated at 40 amps with 125/250 minimum volt range is required. A 50 amp range cord is not recommended but if used, it should be marked for use with nominal 13⁄8” diameter connection openings. Care should be taken to center the cable and strain relief within the knockout hole to keep the edge from damaging the cable."

Currently the 6 foot 50 amp cord is preventing the range from sitting flush against the wall. I have already moved the box from the floor where it was clearly in the way to the wall. Even with that done, it is extremely difficult to get the cable out of the way in order to get the stove all the way to the wall. I'm going to have to move it out again to install an anti-tip bracket, so I figure I may as well switch to a 4 foot 40 amp cord. At that point is there any reason to change the breaker from 50 amps to 40?

 

[wwhitney]

As long as the range manual doesn't call for a 40 amp breaker, and as long as the wiring in the wall has an ampacity of 50 amps, leaving the 50 amp breaker is fine. [The latter means #6 Cu if using a 60C wiring method likes NM cable; or #8 Cu if using a 75C wiring method like MC cable or conduit; or #6 Al.]

Cheers, Wayne

 

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[Reach4]

I would think that an electric range tipping over would be a pretty rare event.

 

[WorthFlorida]

The new ranges are very lightweight. The oven doors are taller than the old ranges of 30 years ago or so. With the oven door fully opened and pushing down on the door, the range will tip forward. I've tried it on my Samsung and it is scary. You sure don't want anything hot dumping off the stove stop with a little kid nearby. I put in the tip over bracket on my last house and my current home.

 

[Jadnashua]

The electrical code calls for the wiring and breaker to be derated to 80% when the device can be on for extended periods of time...so, if they call for a 50A breaker, you should use it along with wiring that can handle that current. 80% of that 50A circuit would be 40A you'd be allowed to use long-term. If you were to replace it with a 40A breaker, in theory, you'd only be able to draw 32A continuously from the circuit. You'll run into similar things if you ever install an EVSE to charge an electric vehicle. The smaller the gauge wire (bigger number), the more voltage drop you'll have, and things can heat up. Over time, that heat can damage things. Circuit breakers tend to be like a thermostat...enough current, the sensor gets hot, and it trips the thing...long-term, constant high current can do it, as can a momentary exceptionally high current (like a short).

So, if the instructions say you can use a 40A cord, but they still could call for a 50A circuit...sort of like plugging in a lamp...might only be a 50W bulb, but the wiring TO the outlet, because it's usually on a 15A circuit, would still need to be at least 14G...the CB is to protect the wiring up to the plug...what you plug in is dictated by the device.

 

[hj]

The anti-tipping bracket is a CYA by the manufacturers in case it ever did happen.

 

[wwhitney]

The electrical code calls for the wiring and breaker to be derated to 80% when the device can be on for extended periods of time

Yes, but that doesn't apply to an electric range. And to be a bit more precise, the breaker is derated to 80% for continuous loads, but the wires size needs to be matched to the breaker. If for some reason the breaker weren't the weakest link, the wires would not need any derating for continuous loads.

Cheers, Wayne