shared appliances one circuit question

[Stevenfyeager]

I read from 210.19 A (3) year 2011, I can share (tap) a 30 amp oven with a 240 v 20 amp microwave on an existing 50 amp circuit. But what if the manufacturer (Kitchen Aid KMBPP100ESS) says: "a dedicated circuit is required" ? I saw some older posts like this but wasn't sure if the manufacturer takes priority. Thank you.

 

[LarryFine]

But what if the manufacturer (Kitchen Aid KMBPP100ESS) says: "a dedicated circuit is required" ? I saw some older posts like this but wasn't sure if the manufacturer takes priority.

Yeah, it does. That's exactly what the instruction addresses.

You can still consider who will see it and decide what to do.

 

[Stevenfyeager]

Yeah, it does. That's exactly what the instruction addresses.

You can still consider who will see it and decide what to do.

Thanks. It still goes against my gut feeling,...to have a number 12 cable downstream from a 50 amp breaker.

 

[LarryFine]

Thanks. It still goes against my gut feeling,...to have a number 12 cable downstream from a 50 amp breaker.

No different from #18 fixture wires on 15a or 20a circuits.

If you do run a new circuit, make it for the smaller load.

 

[electrofelon]

I've never been quite clear on this situation. It seems that allows the conductor to be tapped and a resulting tap conductor, but does that allow me to put a 5-15/20 receptacle on it ?

 

[wwhitney]

I've never been quite clear on this situation. It seems that allows the conductor to be tapped and a resulting tap conductor, but does that allow me to put a 5-15/20 receptacle on it ?

210.19(A)(3) Exception 1 applies to "electric ranges, wall-mounted electric ovens, and counter mounted electric cooking units." Are there any such units that would have a 5-15 or 5-20 plug on them?

If so, and you use a receptacle for connecting it, sure. More likely would be a 6-20 plug, I would think.

Cheers, Wayne

 

[tortuga]

I've never been quite clear on this situation. It seems that allows the conductor to be tapped and a resulting tap conductor, but does that allow me to put a 5-15/20 receptacle on it ?

210.19(A)(3) Exception 1 applies to "electric ranges, wall-mounted electric ovens, and counter mounted electric cooking units." Are there any such units that would have a 5-15 or 5-20 plug on them?

If so, and you use a receptacle for connecting it, sure. More likely would be a 6-20 plug, I would think.

Cheers, Wayne

There are many "wall mounted" ovens that slide into cabinetry I dont see a microwave oven any different.
The tap cannot be longer than necessary for servicing the appliance which I take to mean the whip, so if that 50A circuit is #6AL or #8CU you might need to run that to the jbox behind the wall mounted oven.

 

[Knightryder12]

I've never been quite clear on this situation. It seems that allows the conductor to be tapped and a resulting tap conductor, but does that allow me to put a 5-15/20 receptacle on it ?

I don't think you can put a 5-15/20 receptacle on the tap conductors as the exception says that the tap conductors "include any conductors that are a part of the leads supplied with the appliance that are smaller than the branch-circuit conductors."
So to me that means no receptacle, it has to be hardwired.

 

[wwhitney]

I don't think you can put a 5-15/20 receptacle on the tap conductors as the exception says that the tap conductors "include any conductors that are a part of the leads supplied with the appliance that are smaller than the branch-circuit conductors."

I don't see how you go from a statement that is inclusive to a conclusion that is exclusive.

Cheers, Wayne

 

[wwhitney]

I read from 210.19 A (3) year 2011, I can share (tap) a 30 amp oven with a 240 v 20 amp microwave on an existing 50 amp circuit. But what if the manufacturer (Kitchen Aid KMBPP100ESS) says: "a dedicated circuit is required" ? I saw some older posts like this but wasn't sure if the manufacturer takes priority. Thank you.

If that's the language in the manual, "a dedicated circuit is required," that's not the same as calling for an individual branch circuit. No problem, the tap conductors will be dedicated to the 240V 20A microwave. : - )

If you don't buy that, you'd need to figure out a place for a 20A OCPD to create a dedicated branch circuit, which could be tapped from the 50A branch circuit/now feeder also.

Cheers, Wayne

 

[wwhitney]

There are many "wall mounted" ovens that slide into cabinetry I dont see a microwave oven any different.
The tap cannot be longer than necessary for servicing the appliance which I take to mean the whip, so if that 50A circuit is #6AL or #8CU you might need to run that to the jbox behind the wall mounted oven.

Ah, if you take the position that a built-in microwave oven is a "wall-mounted electric oven," and it has a 5-15 plug on it, then I agree you could run full size branch circuit conductors to a junction box and tap them with #12 pigtails to a 5-15 receptacle installed in the junction box.

Cheers, Wayne

 

[tortuga]

Ah, if you take the position that a built-in microwave oven is a "wall-mounted electric oven," and it has a 5-15 plug on it, then I agree you could run full size branch circuit conductors to a junction box and tap them with #12 pigtails to a 5-15 receptacle installed in the junction box.

Cheers, Wayne

If an inspector did not like it and wanted to split hairs he could say the pigtail to the receptacle is not necessary for servicing the appliance so those would also need to be the size of the branch circuit conductors.

 

[wwhitney]

If an inspector did not like it and wanted to split hairs he could say the pigtail to the receptacle is not necessary for servicing the appliance so those would also need to be the size of the branch circuit conductors.

I don't believe that a 5-15 receptacle will take #6 or #8. So using pigtails in a junction box would be the shortest you could make those tap conductors, and hence compliant with the Exception.

If I'm wrong about the 5-15 receptacle, then I agree with your hair splitting inspector. : - )

Cheers, Wayne

 

[david luchini]

Ah, if you take the position that a built-in microwave oven is a "wall-mounted electric oven," and it has a 5-15 plug on it, then I agree you could run full size branch circuit conductors to a junction box and tap them with #12 pigtails to a 5-15 receptacle installed in the junction box.

Cheers, Wayne

That would be a violation of 210.21.

 

[wwhitney]

That would be a violation of 210.21.

Ah, thanks, specifically 210.21(B).

OK, so you can't ever use a 5-15 or 5-20 receptacle on a 50A branch circuit, even under 210.19(A)(3) Exception. Scratch my earlier comments.

I guess you could use a NEMA 5-50 or 14-50 receptacle, along with a plug adapter to plug in your wall mounted electric oven with a 5-15 cord? Not sure if the plug adapter is a problem. Better to find a hardwire-able option.

Cheers, Wayne

 

[wwhitney]

But what if the manufacturer (Kitchen Aid KMBPP100ESS) says: "a dedicated circuit is required" ?

I looked at the installation instruction for KMBP100ESS (just one P), and I didn't see that language, but it does say:

"The microwave oven rated 120/240 V, 20 A, has 4 wires (L1, L2, N, and G) in the flex conduit, and should be connected to a 20 A maximum-rated circuit, overcurrent protected on both the L1 and L2 circuits."

So if "should be" is mandatory language, then you'd need to provide a 20A branch circuit.

Cheers, Wayne

 

[a.bisnath]

I read from 210.19 A (3) year 2011, I can share (tap) a 30 amp oven with a 240 v 20 amp microwave on an existing 50 amp circuit. But what if the manufacturer (Kitchen Aid KMBPP100ESS) says: "a dedicated circuit is required" ? I saw some older posts like this but wasn't sure if the manufacturer takes priority. Thank you.

Seen this before! never ends well, I firmly believe in following manufacturer's specs especially in cases where aluminium wire is used. I would also ensure individual circuit breakers

 

[Knightryder12]

I don't see how you go from a statement that is inclusive to a conclusion that is exclusive.

Cheers, Wayne

I am not following you here, maybe I am ignorant on this topic as I do not do residential work. But wouldn't the tapped conductors stop at the receptacle? I know that the illustrations in the handbook are not code, but none of them ever show a receptacle at the end of the tap, they all show a hardwired connection.

 

[tortuga]

That would be a violation of 210.21.

Good point I had to look that up again becasue I remember doing it for welders, but there is an exception in there for welders and lighting.

 

[tortuga]

But wouldn't the tapped conductors stop at the receptacle?

Generally the NEC does like to think it covers appliance cords and whips especially to fastened in place equipment.
We were talking about 210.19(C) Ex 1. that allows taps to a household cooking appliance, as long as they are not longer than necessary for servicing the appliance .
They probably did not have a receptacle in mind when they wrote that as the conductors before a receptacle would not be considered 'necessary for servicing' though one could could probably make a clever argument as to what 'servicing' means?
Is servicing
a) Supplying power to put it in service
or
b) Ability to pull out the oven to clean / repair or 'service' it?