40 Amp Range Feed

[Pizza]

I'm wiring for a dual fuel range. The specs say its needs a 40 amp feed. Cord and plug connection.
My question is can I run a 8-3 romex on a 2 pole 40 amp breaker and still put in a 50 amp range recep?
422.33 (C) says that the receptacle shall not be rated less than the rating of any appliance connected thereto. But it doesn't say it can't be bigger.
Could the inspector baulk because maybe in the future someone could put a range that draws 50 amps and then the romex would not be rated for it.
I don't want to use 6-3 romex if I don't have to, because its not as flexible in the box and more expensive.

 

[iwire]

Table 210.24 says you can.

 

[jumper]

I'm wiring for a dual fuel range. The specs say its needs a 40 amp feed. Cord and plug connection.
My question is can I run a 8-3 romex on a 2 pole 40 amp breaker and still put in a 50 amp range recep?
422.33 (C) says that the receptacle shall not be rated less than the rating of any appliance connected thereto. But it doesn't say it can't be bigger.
Could the inspector baulk because maybe in the future someone could put a range that draws 50 amps and then the romex would not be rated for it.
I don't want to use 6-3 romex if I don't have to, because its not as flexible in the box and more expensive.

You are good. Common install.

 

[infinity]

Just curious what is the KW rating of the range. If the spec says 40 amps then you'll need 40 amp conductor and a 40 amp OCPD. There is no standard 40 amp receptacle/cord and plug set so you would need to use a 50 amp device and cord.

 

[malachi constant]

Let me get this straight. The breaker and wire are rated for 40A. There is no standard 40A plug/cord, 50A is typically used in a situation like this. If someone in the future plugs in a 50A range they will be told in the installation literature to verify it is fed from a 50A circuit breaker, at which point they would presumably be alerted to the need to upgrade breaker and feeder. I'll buy that.

I don't understand what table 210.24 has to do with anything. The related text says "The requirements for circuits that have two or more outlets..." I have no idea what the purpose of this section is, but doesn't look like it applies to the OP.

Hypothetical here. If we lived in a world with two main types of ranges (40A and 50A), and each range used a different plug (40A configuration for the first, 50A for the second) would the install be recommended? In that case you would say "provide the 40A receptacle, end of story." Right? Or does code allow something like this? I suppose it is akin to feeding a 100A subpanel from a 60A breaker, which I know is allowed. The difference between panels and appliances is that panel has an infinite number of breaker combinations and loads that could be put on it, whereas the 50A appliance receptacle, in this hypothetical world, would only have one thing that could be plugged into it: a 50A load. I guess what my post really comes down to is I'm surprised to hear 40A appliances come with a 50A plug, and if that really is true then I would not be surprised that code allows what the OP proposes.

 

[kwired]

Let me get this straight. The breaker and wire are rated for 40A. There is no standard 40A plug/cord, 50A is typically used in a situation like this. If someone in the future plugs in a 50A range they will be told in the installation literature to verify it is fed from a 50A circuit breaker, at which point they would presumably be alerted to the need to upgrade breaker and feeder. I'll buy that.

I don't understand what table 210.24 has to do with anything. The related text says "The requirements for circuits that have two or more outlets..." I have no idea what the purpose of this section is, but doesn't look like it applies to the OP.

Hypothetical here. If we lived in a world with two main types of ranges (40A and 50A), and each range used a different plug (40A configuration for the first, 50A for the second) would the install be recommended? In that case you would say "provide the 40A receptacle, end of story." Right? Or does code allow something like this? I suppose it is akin to feeding a 100A subpanel from a 60A breaker, which I know is allowed. The difference between panels and appliances is that panel has an infinite number of breaker combinations and loads that could be put on it, whereas the 50A appliance receptacle, in this hypothetical world, would only have one thing that could be plugged into it: a 50A load. I guess what my post really comes down to is I'm surprised to hear 40A appliances come with a 50A plug, and if that really is true then I would not be surprised that code allows what the OP proposes.

Lets just look at the similarity with 15 and 20 amp receptacles.

One difference is there is not a 40 amp receptacle.

Otherwise we have 15 amp plugs that will plug into a 20 amp receptacle, and 15 amp receptacles are allowed on a 20 amp circuit as long as it is a multioutlet circuit.

They do make 40 amp range cords - they have smaller conductors than a 50 but still have a 50 amp plug.

You also have the ability to connect multiple cooking appliances like cooktops and ovens to the same 50 amp branch circuit even though the individual appliance may possibly only be rated low enough that a 15 or 20 amp circuit would be sufficient to power it.

I think there is not a significant number of cases where there was a problem with the practices that are allowed to justify any changes in codes that apply. Many of the rules in this area have not really changed for a long time.

 

[malachi constant]

Lets just look at the similarity with 15 and 20 amp receptacles.

One difference is there is not a 40 amp receptacle.

Otherwise we have 15 amp plugs that will plug into a 20 amp receptacle, and 15 amp receptacles are allowed on a 20 amp circuit as long as it is a multioutlet circuit.

OK, I follow. you feed a receptacle with #14s from a 15A breaker. Someone plugs in an appliance with a rated load of ~20A. Breaker probably trips. Meets code, user learns his lesson, no problem here. You are right, this is pretty much the same scenario as above.

You also have the ability to connect multiple cooking appliances like cooktops and ovens to the same 50 amp branch circuit even though the individual appliance may possibly only be rated low enough that a 15 or 20 amp circuit would be sufficient to power it.

Can't do that in any residential kitchen I've ever seen. Maybe theoretically one could rewire the circuit to allow 15A/20A devices to tap into it, but again I've never seen or heard of that being done. I don't see how that table applies.

Don't worry about it. I'm fine considering this a dead horse. I don't need to see how to weave my way through the code here - such an oddball scenario. Thanks!

 

[kwired]

OK, I follow. you feed a receptacle with #14s from a 15A breaker. Someone plugs in an appliance with a rated load of ~20A. Breaker probably trips. Meets code, user learns his lesson, no problem here. You are right, this is pretty much the same scenario as above.



Can't do that in any residential kitchen I've ever seen. Maybe theoretically one could rewire the circuit to allow 15A/20A devices to tap into it, but again I've never seen or heard of that being done. I don't see how that table applies.

Don't worry about it. I'm fine considering this a dead horse. I don't need to see how to weave my way through the code here - such an oddball scenario. Thanks!

210.19(3) exception 1 allows connecting cooking appliances to a 50 amp circuit - the taps must be at least 20 amp conductors. It does not mention nor prohibit receptacles. Without further research I would guess you need to use a 50 amp receptacle, but the cord would only need to be 20 amps if the appliance was 20 amp or less.

I don't know you consider a dead horse. You can use a 40 or 50 amp circuit and 50 amp receptacle to supply a 40 amp cooking appliance.

 

[jwelectric]

A 16kw electric range can be wired to a 40 amp receptacle.

16000/240=66.666

40 times 240 equals 9600va

16 exceeds 12 by 4
Now increase the demand in column ?C? by 5% for each kw that the 16kw range exceeds 12
8 times 120% equals 9.6 or 9600 the same as a 40 amp receptacle.

For more information see 210.21(B)(4) and 210.19(A)(3)