Range & Dryer Demand — Tables 220.55 and 220.54

8 kW. Table 220.55 Column C gives a maximum demand of 8 kW for one household range rated over 1¾ kW through 12 kW — and that is a demand in kilowatts, not a percentage. This is the single most misread table in Article 220. A 9 kW range and a 12 kW range both count as 8 kW, so the nameplate barely matters at this size. The 8 kW figure already has diversity built into it: nobody runs every element and the oven simultaneously for long.

Note 1 to Table 220.55 applies: for ranges over 12 kW through 27 kW of the same rating, the Column C figure is increased by 5% for each additional kilowatt above 12. A 16 kW range is 4 kW over, so 8 kW × (1 + 20%) = 9.6 kW. Note that the 5% applies to the table value, not to the nameplate — a mistake that inflates the answer badly. Even a 27 kW commercial-style range only reaches 14 kW of demand.

5,000 VA or the nameplate, whichever is larger, per NEC 220.54. So a 4,800 W dryer still counts as 5,000 VA, and a 5,600 W one counts as 5,600. The demand factor is 100% for one through four dryers, and only starts reducing at five: 85% at five, 75% at six, down to 50% at ten. In a single-family house there is no reduction at all — the dryer is simply its 5,000 VA floor.

Because connected load and simultaneous load are different quantities, and services are sized for the second. Ten apartments have ten ranges totalling 120 kW installed, but the probability that all ten are roasting at full output at the same moment is effectively zero. Table 220.55 counts those ten at 25 kW — an 79% reduction. Without demand factors every multifamily service in the country would be roughly four times larger than it needs to be, at enormous cost and no safety benefit.

Small appliances. Column A covers cooking appliances over 1¾ kW and under 3½ kW, Column B covers 3½ kW through 8¾ kW, and both give percentages rather than kilowatts. Note 3 permits using them in lieu of Column C for appliances in those ranges — which matters because Column C's flat 8 kW would otherwise penalise a small unit. A single 6 kW wall oven is 4.8 kW under Column B against 8 kW under Column C.

Often yes, and it saves considerable load. Note 4 to Table 220.55 permits a counter-mounted cooking unit and up to two wall ovens supplied from a single branch circuit and located in the same room to be treated as a single range by adding their nameplate ratings together. A 7 kW cooktop plus a 5 kW oven totals 12 kW, which is then a single 8 kW range demand rather than two separate appliance loads.

Neither. A gas range has no significant electrical cooking load — only its ignition, controls and clock, counted as an ordinary appliance. And Table 220.55 covers household equipment only; a commercial kitchen uses NEC 220.56, which is a completely different set of demand factors (100% for one or two units, then 90%, 80%, 70% and 65%) with a floor at the sum of the two largest pieces of equipment.

No — and this catches people who work both methods on the same house. The 220.82 optional method takes appliance nameplate ratings at full value and then applies its own single reduction: the first 10 kVA at 100% and the remainder at 40%. Tables 220.55 and 220.54 belong to the Part III standard method. Applying a range demand factor and then the 40% remainder factor double-counts the diversity and understates the load.