Table 220.55 calculation Dilemma

[KBot9]

I have a client who originally specified (for the sake of simplicity I'll make up the numbers)... 10 Apartment Free-Standing Range top/Oven combo Appliances rated at 10kW...all to be on a new dedicated feeder riser.
220.55 Column C would have me calculate the Max Demand based on 10 units total at 25kW.

No Prob.

Now, the client would like to revise his kitchen design to instead be 10 WALL OVENS rated at say 5kW and 10 COUNTER COOKTOPS rated at 5kW. The same functions as before with the same total nameplate ratings just split to 2 units each fed by a separate breaker but on the same feeder riser. However now 220.55 says I have to use Column B for TWENTY units, so Demand Factor of 28% (100,000 wats x.28 = 28kW)

Same function, same utilization, same total wattage: one is 25kW or is 28kW.

I know I can use either column for the lowest rating when the units are the same # of units, but am I stuck with 28 now vs 25 or can I STILL option to use 25kW?

 

[petersonra]

I think you know the answer. You have to follow whatever the rules are regardless of whether they make sense to you.

 

[KBot9]

Thx Peter, I agree.

However, I think part of my confusion comes from Note 4. So per Note 4...say I feed the new counter cooktop and wall oven with a single branch circuit (calculated per note 4 combining the nameplates, would those two then be considered per Note 4 to be "one range" to count towards the feeder/Service Load and so in my example above then be 10 "appliances" for the purpose of the chart?

 

[petersonra]

Thx Peter, I agree.

However, I think part of my confusion comes from Note 4. So per Note 4...say I feed the new counter cooktop and wall oven with a single branch circuit (calculated per note 4 combining the nameplates, would those two then be considered per Note 4 to be "one range" to count towards the feeder/Service Load and so in my example above then be 10 "appliances" for the purpose of the chart?

I don't see how wiring them in any particular way changes them from two appliances into one.

 

[KBot9]

How I'm reading Note 4:

The third part of Note 4 says " The branch-circuit load for a counter-mounted cooking unit and not more than two wall-mounted ovens, all supplied from a single branch circuit and located in the same room, shall be calculated by adding the nameplate rating of the individual appliances and treating this total as equivalent to one range. "

One range. The First part of Note 4 says..." It shall be permissible to calculate the branch-circuit load for one range in accordance with Table 220.55. "
If I can calculate a counter top and wall oven who are 5kW each as One Range per Table 220.55 then I can size the branch circuit at 8kW. If I can size the Branch Circuit as 8kW as far as the code goes...why cant I use 8kW towards the service FEEDER rating?

 

[petersonra]

Cause it gives you dispensation on the branch circuit load but says nothing about the feeder?

What does the feeder calc require? Total up the bc loads or total up the individual appliances?