Odd range nameplate 110.3(B) VS T220.55

tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Hi-end dual fuel Monogram range, manufacturers instructions say to install a 50A 240V circuit, namplate says 50A 240V (dual ovens are electric, cooktop gas).
Oddly the nameplate is not in kW and its 240V not a 120/240V circuit. I think every range I have ever seen was rated in kW.
So no problem easy math 50 X 240 = a 12kw range and per T220.55 column C it is 8kW so can be on a 8/2 NM 40A circuit (with a 50A receptacle& cord).
Or does 110.3(B) require a 50A circuit and 6/2 NM?
 
S

suemarkp

Senior Member
Location
Kent, WA
Occupation
Retired Engineer
That's a tough one. The instructions say their 48" wide range needs a 50A circuit (40A for the 30" and 36"). But if you add up the highest burner settings for the ovens, it is only around 6750 watts. Maybe they have some mode that runs the top and bottom burners at the same time. Even if they do (say a self clean mode), I wouldn't think they would run all that long before they need to turn off and that is still only 11 KW.

They may be wanting provisions for electrical in case you add an all electric range later?? Instructions seem to be cookie cutter generic.

If you are installing a new circuit, then I'd go with 6-3 just so they have future options. If it is existing 8-3, I think it will work just fine but hope the inspector comes before the range is installed. Manual indicates you need a neutral, so it is x-3 cable, not x-2.
 
infinity

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
If the instructions are part of the listing of the unit then you have to just follow them with a 50 amp circuit. Manufacturers often require things that exceed the NEC even if they don't make sense.
 
Fred B

Fred B

Senior Member
Location
Upstate, NY
Occupation
Electrician
infinity said:
If the instructions are part of the listing of the unit then you have to just follow them with a 50 amp circuit. Manufacturers often require things that exceed the NEC even if they don't make sense.
Click to expand...
I wouldn't run anything less AFA the wiring especially for "plug in" units, can always have a smaller breaker if needed for equipment listing later, but much harder to install larger wire later.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Imo, you need a 50 amp circuit. It won't hurt to have it. 40 amps will probably work especially since trhe ovens would be on and off via t-stat.

Depending on how you see this your demand may be 11kw. 2 ovens would use col. c, depending on their kw, and for 2 appliances the demand is 11kw. = 45 amps

Note 4 states for a cooktop and up to 2 ovens you add them together and treat as one unit- as you did. But the cooktop is gas so.... are e back to 2 ovens and using col C which means 45 amps again.....idk. Just use a 50 amp circuit
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Thanks for the replies all.
There is more to the story, the range is already wired with 8/3 on a 40A.
The customer noticed the 40A breaker in the panel and asked that it be changed to a 50A.
I contacted the manufacturer to see if its really part of the listing and am awaiting a reply.
 
tortuga

tortuga

Code Historian
Location
Oregon
Occupation
Electrical Design
Well the tech support called back and said its not part of the CSA listing but a strong recommendation.
I double checked with the AHJ here (whom approved the install) and now he is confused about what the 'maximum load to be served' is in [2023] 210.19 (C) or [2020] and earlier 210.19(3)
Household Ranges and Cooking Appliances. Branch-
circuit conductors supplying household ranges, wall-mounted
ovens, counter-mounted cooking units, and other household
cooking appliances shall have an ampacity not less than the rat-
ing of the branch circuit and not less than the maximum load to
be served. For ranges of 83⁄ 4 kW or more rating, the minimum
branch-circuit rating shall be 40 amperes.
Click to expand...
Is the 'load to be served' the nameplate rating or the load as calculated in 220.1 and T220.55 Note 4?
 
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