Example D2 (a) optional calculation

[parttimemuso]

Re: dwelling calculation; page 70-717. Why is the range caluclated at 12 KVA for feeder hots but downgraded to 8 KVA, as per Table 220.55, prior to 70% multiplier for calcualting neutral? Base KVA rating should be the same for either hot or neutral calculation prior to using multiplier I would think. I haven't found an explanation for this. Any answers?

 

[Dennis Alwon]

The neutral for a range is generally used for lights in the oven and perhaps a downdraft motor. Some of the higher scale ranges don't even use a neutral.

 

[parttimemuso]

I understand compeltely about the neutral on the oven and how minimal it usually is load-wise. My question is why is the base load KVA figure knocked down from 12 to 8 prior to adding the 70% multiplier for neutral and why is there no explanation for it? As a comparison the dryer load is at full 5 kva multiplied by 70% for neutral calculation. The dryer essentially doesn't have any more 120 volt bells and whistles ie-light bulbs or timers than an oven does. Why does the base number on a dryer stay the same prior to neutral calculation?