Load calculations for ranges and ovens

[rookie4now]

220.19 says that for appliances of 1750 watts or more we are supposed to use table 220.19 and the applicable notes to calculate the load. The question I have, is what do you do in the case where you have no idea what range will be installed and therefore don't know the total watts?

Is there a default number?

Thanks.

 

[S'mise]

Good question, I believe you have to know the rating of the range. If I had to guess I would say 40Amp min. See 210.19(A)(3) "....For ranges of 8.75KW or more, the minimun branch-circuit rating shall be 40 amperes."

 

[LarryFine]

Good question, I believe you have to know the rating of the range. If I had to guess I would say 40Amp min. See 210.19(A)(3) "....For ranges of 8.75KW or more, the minimun branch-circuit rating shall be 40 amperes."

40 A.

 

[Rockyd]

What will they pay for? 2 #8, a #10 and ground is minimum (40A hole), can you upsell to #6, and sell it as a feature (50A hole)? I'm assuming it all depends on who the clint is.

Looking at table 220.55 they assume you know the rating of the equipment (cooking device) to be installed.

Now this isn't code, but the additional information from the NEC 2005 Handbook states the following -

For household electric ranges, and other cooking appliances, the size of the conductors must be determined by the rating of the range. According to table 220.55 for one range rated 12 kW or less, the maximum demand load is 8 kW (8kVA per 220.55 and #8 AWG copper conductors with 60' C insulation would suffice. Note that 210.19(A)(3) does not permit the branch circuit rating of a circuit supplying household ranges with a nameplate rating or 8.25 to be less than 40 amps.

 

[S'mise]

guess game

guess game

Yes, best to run it big just incase. You will probably run the 40A and they will put in a 3KW stove. At least your covered. Why don't you call the HO an convince them to use gas? It's the choice of top chefs. :grin:

 

[Dennis Alwon]

Why don't you call the HO an convince them to use gas? It's the choice of top chefs. :grin:

Actually many chefs like gas cooktops and electric ovens.

I would also pull a number 8 wire but lately we have been seeing more ranges coming in at 50 amp which would require a #6. Get the info or tell them they will have to pay for the larger wire.

I have never seen a full sized range (not apt range) that were less than 40 amp.

 

[rookie4now]

Actually the question was for load calculating only. I seem to remember reading somewhere that 8kw is used when the load is unknown but I can't find anything now.