range calculations? help please

[kmc]

what is the total load calc for for a 6 kw + 4kw + 4kw ranges? I believe Mikes book is incorrect. They show adding all together and applying table 220.5 column C. Your help would be greatly appreiciated

 

[1793]

Give us your thoughts, calculations and lets go from there.

 

[kmc]

my thoughts from reading the code book and stalcups book is: apply the demand factor of column B being 65% of (6+4+4= 14kw) 65% of 14kw=9.1kw
This may not be the best example because the answer still comes fairly close to holts method. 8.8kw, but with other questions that use column A & B the answers diverge even further.

 

[1793]

my thoughts from reading the code book and stalcups book is: apply the demand factor of column B being 65% of (6+4+4= 14kw) 65% of 14kw=9.1kw
This may not be the best example because the answer still comes fairly close to holts method. 8.8kw, but with other questions that use column A & B the answers diverge even further.

(6+4+4)=3 units.
Unless I'm missing something you would need to use the 55% in column B.

 

[kmc]

you are right my mistake, but that is the correct way to apply the demand factors. So applying 55% to 14kw (6+4+4)= 7.7kw And to take this another step say 2kw + 5kw + 9kw= (2kw x .80) +(5kw x .80) + 8kw= 13.6 kw. Thanks for your reply and time.

 

[1793]

you are right my mistake, but that is the correct way to apply the demand factors. So applying 55% to 14kw (6+4+4)= 7.7kw And to take this another step say 2kw + 5kw + 9kw= (2kw x .80) +(5kw x .80) + 8kw= 13.6 kw. Thanks for your reply and time.

This is not my strong suit, but that is how I would do it.

Here to offer help and to LEARN.

 

[kmc]

Thanks for your input norb, that is how the nec seemed to explain it, , So any way thanks much for your help. If any one else has any input I would be very greatful.

 

[Wes G]

Looks good.

Looks good.

That's the way to figure it. As long as you pay close attention to the notes for T220.55 and use them in conjunction with the table you can't go wrong.
___________________
Wes Gerrans
Instructor
Northwest Kansas technical College
Goodland, KS