Example No. D1(b) One-Family Dwelling

Assume same conditions as Example No. D1(a), plus addition of one 6-ampere, 230-volt room air-conditioning unit and one 12-ampere, 115-volt room air-conditioning unit,* one 8-ampere, 115-volt rated waste disposer, and one 10-ampere, 120-volt rated dishwasher. See Article 430 for general motors and Article 440, Part VII, for air-conditioning equipment. Motors have nameplate ratings of 115 V and 230 V for use on 120-V and 240-V nominal voltage systems.

From Example No. D1(a), feeder current is 78 amperes (3-wire 240 volts).

	Line A	Neutral	Line B
Amperes from Example No. D1(a)	78	61	78
One 230-V air conditioner	6		6
One 115-V air conditioner and 120-V dishwasher	12	12	10
One 115-V disposal		8	8
25% of largest motor (see 430.24)	3	2	2
Total amperes per line	99	83	104
Therefore, the service would be rated 110 A.
*(For feeder neutral, use largest of the two appliances for unbalance.)