**Cooking Appliances**

Total Connected Load

A“Range” is a stationary cooking appliance containing several burners built into a cooktop surface with at least one oven compartment. Ranges are usually rated in kilowatts (kW) based on a label, or nameplate, usually located somewhere on the appliance. The nameplate rating of a range is its total wattage; including all of its components (burners, ovens, clocks, timers, etc.). The Code refers to this as the “total connected load.”

Although there are several components in a range they are rarely used simultaneously, holidays being the exception ! Also, the more cooking appliances there are in one building, or in an apartment complex for instance, the less likely that they will all be used at the same time. Because of these circumstances the Code allows us to reduce the total load for cooking appliances on the service.

Although there are several components in a range they are rarely used simultaneously, holidays being the exception ! Also, the more cooking appliances there are in one building, or in an apartment complex for instance, the less likely that they will all be used at the same time. Because of these circumstances the Code allows us to reduce the total load for cooking appliances on the service.

Demanded Load

This decrease on the service is call the “demand factor.” By definition the demand factor is a reduced percent of the “total connected load” of a service. After a demand factor has been applied to the total connected load it will be called the "demand load." Article 220.55 of the Code applies to residential feeder and service demands for ranges and other cooking appliances.

Table 220.55 gives the demand loads for household electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances over 1-3/4 kW to 27 kW rating.

*220.55 Electric Ranges and Other Cooking Appliances - Dwelling Unit(s). The load for household electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances individually rated in excess of 1-3⁄4 kW shall be permitted to be calculated in accordance with Table 220.55. Kilovolt-amperes (kVA) shall be considered equivalent to kilowatts (kW) for loads calculated under this section.*Table 220.55 gives the demand loads for household electric ranges, wall-mounted ovens, counter-mounted cooking units, and other household cooking appliances over 1-3/4 kW to 27 kW rating.

Column “C”

Applying Table 220.55 to ranges is simple.

For example: One range with a nameplate rating of 12 kW. Table 220.55, Column “C” is applied to appliances rated between 1-3/4 kW (minimum) to 12 kW (maximum). Seeing as we only have one appliance within Column “C” the demand load would be...

For example: One range with a nameplate rating of 12 kW. Table 220.55, Column “C” is applied to appliances rated between 1-3/4 kW (minimum) to 12 kW (maximum). Seeing as we only have one appliance within Column “C” the demand load would be...

1 Range at 12 kW = 8 kW

A 12 kW range, in this instance, would be reduced by 67% to 8 kW. Remember, this is the kW demand to be used in calculating the feeder and service size, not the branch circuit, we’ll get to that later !

What about two ranges at 12 kW. We’re still in Column “C” but the number of appliances is now “2”...

What about two ranges at 12 kW. We’re still in Column “C” but the number of appliances is now “2”...

2 Ranges at 12 kW = 11 kW

The demanded load is 11 kW, that’s a 46% reduction. That’s not too hard, is it ?

Wait a minute ! How about 30 ranges in one house ! Looks crazy, Table 220.55 gives the demand load for household cooking appliances but not necessarily in one residence. This could be an apartment building with 30 units (one 12 kW range in each unit). The only requirement here is that they all have to be fed by one set of feeders from one main service.

According to Table 220.55, Column "C" those 30 ranges would have a demanded load of 15 kW plus 1 kW for each range, or...

Wait a minute ! How about 30 ranges in one house ! Looks crazy, Table 220.55 gives the demand load for household cooking appliances but not necessarily in one residence. This could be an apartment building with 30 units (one 12 kW range in each unit). The only requirement here is that they all have to be fed by one set of feeders from one main service.

According to Table 220.55, Column "C" those 30 ranges would have a demanded load of 15 kW plus 1 kW for each range, or...

15 kW + 30 kW = 45 kW (Col. “C”)

Remember, the total connected load of 30 ranges at 12 kW is 360 kW (30 x 12 kW), that’s a reduction to 12.5% of their nameplate rating. The average range, in this case, is only 1.5 kW per appliance. Wonder would happen if all these people tried to cook a big Thanksgiving dinner at the same time ?

Note 1

Table 220.55 is based on cooking appliances rated a maximum of 12 kW. Note 1 (located under Table 220.55) allows us to exceed that amount for ranges up to 27 kW, if they all are the same rating. What the code allows us to do is adjust Table 220-55, Column “C” by adding 5% for every one kW, or major fraction (.5 or larger) that the individual range exceeds 12 kW. Remember, Column "C" is based on a maximum of 12 kW per appliance. When you exceed 12 kW you have to add 5% to Column "C." It's kind of like a special 5% tax on ranges.

Taking this a step at a time...

(1) Total the number of cooking appliances.

(2) Determine the maximum demand from Table 220-55, Column ‘C’.

(3) Subtract 12 kW from the kW rating of the appliances, all of the same rating.

(4) Increase the maximum demand from Table 220-55, Column ‘C’ by 5% for each 1 kW, or major fraction thereof (.5 or larger) that the average appliance exceeds 12 kW.

For example; let's calculate 11 ranges rated 13 kW each...

(1) Total the number of cooking appliances. = 11

(2) Look up 11 appliances in Column “C” = 26 kW

(3) Subtract 12 kW from nameplate rating (13 kW - 12 kW) = 1 kW

(4) Increase the demand Column “C” by 5% (26 kW + 5%) = 27.3 kW

The key here is to first, go to the the "number of appliances column" and find the kW demand from Column “C.” This will give us the demand of the appliances if they were rated 12 kW. We’ll call Column “C” our home base.

Only after finding our Column “C” demand will we be able to add on 5% for every 1 kW, or major fraction (.5 or larger) that we exceed 12 kW by. Let’s try another one.

For example: say we have 20 ranges at 14.5 kW...

(1) Total the number of cooking appliances. = 20

(2) Look up 20 appliances in Column “C” = 35 kW.

(3) Subtract 12 kW from nameplate rating (14.5 kW - 12 kW) = 3 kW.

(4) Increase the demand Column “C” by 15% (35 kW + 15%) = 40.25 kW

*Table 220.55, Note 1: Over 12 kW through 27 kW ranges all of same rating. For ranges individually rated more than 12 kW but not more than 27 kW, the maximum demand in Column C shall be increased 5 percent for each additional kilowatt of rating or major fraction thereof by which the rating of individual ranges exceeds 12 kW.*Taking this a step at a time...

(1) Total the number of cooking appliances.

(2) Determine the maximum demand from Table 220-55, Column ‘C’.

(3) Subtract 12 kW from the kW rating of the appliances, all of the same rating.

(4) Increase the maximum demand from Table 220-55, Column ‘C’ by 5% for each 1 kW, or major fraction thereof (.5 or larger) that the average appliance exceeds 12 kW.

For example; let's calculate 11 ranges rated 13 kW each...

(1) Total the number of cooking appliances. = 11

(2) Look up 11 appliances in Column “C” = 26 kW

(3) Subtract 12 kW from nameplate rating (13 kW - 12 kW) = 1 kW

(4) Increase the demand Column “C” by 5% (26 kW + 5%) = 27.3 kW

The key here is to first, go to the the "number of appliances column" and find the kW demand from Column “C.” This will give us the demand of the appliances if they were rated 12 kW. We’ll call Column “C” our home base.

Only after finding our Column “C” demand will we be able to add on 5% for every 1 kW, or major fraction (.5 or larger) that we exceed 12 kW by. Let’s try another one.

For example: say we have 20 ranges at 14.5 kW...

(1) Total the number of cooking appliances. = 20

(2) Look up 20 appliances in Column “C” = 35 kW.

(3) Subtract 12 kW from nameplate rating (14.5 kW - 12 kW) = 3 kW.

(4) Increase the demand Column “C” by 15% (35 kW + 15%) = 40.25 kW

Note 2

What if we have several cooking appliances at different ratings, some of which are over 12 kW, but none exceeding 27 kW. What we’re going to have to do here is find an average value for all the ranges. Then we’ll be able to treat them similar to Note 1 problems.

Taking it a step at a time...

(1) Total the number of cooking appliances.

(2) Total the nameplate ratings of all cooking appliances (use 12 kW if less than 12 kW).

(3) Divide the total nameplate ratings, by the total number of cooking appliances. This equals the average kW for each cooking appliances.

(4) Increase the maximum demand from Table 220-19, Column ‘C’ by 5% for each 1 kW, or major fraction thereof (.5 or larger) that the average appliance exceeds 12 kW.

For example, Take the following list of appliances...

1 Cooktop at 8-3/4 kW

1 Range at 12 kW

2 Ovens at 16 kW

(1) Total the number of appliances = 4

(2) Total nameplate ratings of all appliances

(use 12 kW for any appliances less than 12 kW) = 56 kW

(3) Divide total rating by number of appliances (average)

(56 kW/4 = 14 kW) = 14 kW

(4) Subtract 12 kW from the average rating (14 kW- 12 kW) = 2 kW

(5) Look up 4 appliances in Column “C” = 17 kW

(6) Increase the demand Column “C” by 10% (17 kW+10%) = 18.7 kW

Don’t forget that appliances rated less than 12 kW must be raised to 12 kW. Then, once we find an average value of all of the appliances (14 kW) we revert back to a Note 1 problem: 4 cooking appliances at 14 kW. Then, it’s just a matter of adding 10% on to Column “C”...

*Table 220.55, Note 2: Over 8-3⁄4 kW through 27 kW ranges of unequal ratings. For ranges individually rated more than 8-3⁄4 kW and of different ratings, but none exceeding 27 kW, an average value of rating shall be calculated by adding together the ratings of all ranges to obtain the total connected load (using 12 kW for any range rated less than 12 kW) and dividing by the total number of ranges. Then the maximum demand in Column C shall be increased 5 percent for each kilowatt or major fraction thereof by which this average value exceeds 12 kW.*Taking it a step at a time...

(1) Total the number of cooking appliances.

(2) Total the nameplate ratings of all cooking appliances (use 12 kW if less than 12 kW).

(3) Divide the total nameplate ratings, by the total number of cooking appliances. This equals the average kW for each cooking appliances.

(4) Increase the maximum demand from Table 220-19, Column ‘C’ by 5% for each 1 kW, or major fraction thereof (.5 or larger) that the average appliance exceeds 12 kW.

For example, Take the following list of appliances...

1 Cooktop at 8-3/4 kW

1 Range at 12 kW

2 Ovens at 16 kW

(1) Total the number of appliances = 4

(2) Total nameplate ratings of all appliances

(use 12 kW for any appliances less than 12 kW) = 56 kW

(3) Divide total rating by number of appliances (average)

(56 kW/4 = 14 kW) = 14 kW

(4) Subtract 12 kW from the average rating (14 kW- 12 kW) = 2 kW

(5) Look up 4 appliances in Column “C” = 17 kW

(6) Increase the demand Column “C” by 10% (17 kW+10%) = 18.7 kW

Don’t forget that appliances rated less than 12 kW must be raised to 12 kW. Then, once we find an average value of all of the appliances (14 kW) we revert back to a Note 1 problem: 4 cooking appliances at 14 kW. Then, it’s just a matter of adding 10% on to Column “C”...

17 kW + 10% = 18.7 kW

Note 3

Up to now we’ve dealt with larger size ranges and other cooking appliances. Note 3 deals with smaller ones...

Remember, Note 3 is in lieu (instead) of the method provided in Column “C.” It is listed for cooking appliances between 1-3/4 up to 12 kW and even more with the use of Notes 1 and 2. In order to use Column “A” all of the appliances must be rated between 1-3/4 up to 3-1/2 kW. In order to use Column “B” all of the appliances must be rated between 3-1/2 up to 8-3/4 kW.

Here are the steps:

(1) Total the number of cooking appliances.

(2) Total the nameplate ratings of all of the cooking appliances.

(3) Multiply the sum by Column ‘A’ by demand factor for appliances between

(4) Multiply the sum by Column ‘B’ by demand factor for appliances between

A Column “A” example: Calculate the demand for four ranges at 3 kW.

(1) Total the number of cooking appliances = 4

(2) Total the sum of all of the appliances (4 kW x 3) = 12 kW

(3) Find the demand factor in Column “A” for 4 appliances = 66%

(4) Multiply the sum by demand factor (12 kW x .66) = 7.92 kW

A Column “B” example: Calculate the demand for seven ranges at 8 kW.

(1) Total the number of cooking appliances = 7

(2) Total the sum of all of the appliances (8 kW x 7) = 56 kW

(3) Find the demand factor in Column “B” for 7 appliances = 40%

(4) Multiply the sum by demand factor (56 kW x .4) = 22.4 kW

Wait a minute ! If we look up 7 ranges in Column “C” the demand is only 22 kW. That’s less than using Column “B” ! Remember, Note 4 says that Column “A” and Column “B” can be used “in lieu” of Column “C.” If you can do better in Column “C” use it. In this case we’re better off using Column “C."

*Table 220.55, Note 3: Over 1-3⁄4 kW through 8-3⁄4 kW. In lieu of the method provided in Column C, it shall be permissible to add the nameplate ratings of all household cooking appliances rated more than 1-3⁄4 kW but not more than 8-3⁄4 kW and multiply the sum by the demand factors specified in Column A or Column B for the given number of appliances. Where the rating of cooking appliances falls under both Column A and Column B, the demand factors for each column shall be applied to the appliances for that column, and the results added together.*Remember, Note 3 is in lieu (instead) of the method provided in Column “C.” It is listed for cooking appliances between 1-3/4 up to 12 kW and even more with the use of Notes 1 and 2. In order to use Column “A” all of the appliances must be rated between 1-3/4 up to 3-1/2 kW. In order to use Column “B” all of the appliances must be rated between 3-1/2 up to 8-3/4 kW.

Here are the steps:

(1) Total the number of cooking appliances.

(2) Total the nameplate ratings of all of the cooking appliances.

(3) Multiply the sum by Column ‘A’ by demand factor for appliances between

__1-3/4 and 3-1/2 kW__.(4) Multiply the sum by Column ‘B’ by demand factor for appliances between

__3-1/2 to 8-3/4 kW.__A Column “A” example: Calculate the demand for four ranges at 3 kW.

(1) Total the number of cooking appliances = 4

(2) Total the sum of all of the appliances (4 kW x 3) = 12 kW

(3) Find the demand factor in Column “A” for 4 appliances = 66%

(4) Multiply the sum by demand factor (12 kW x .66) = 7.92 kW

A Column “B” example: Calculate the demand for seven ranges at 8 kW.

(1) Total the number of cooking appliances = 7

(2) Total the sum of all of the appliances (8 kW x 7) = 56 kW

(3) Find the demand factor in Column “B” for 7 appliances = 40%

(4) Multiply the sum by demand factor (56 kW x .4) = 22.4 kW

Wait a minute ! If we look up 7 ranges in Column “C” the demand is only 22 kW. That’s less than using Column “B” ! Remember, Note 4 says that Column “A” and Column “B” can be used “in lieu” of Column “C.” If you can do better in Column “C” use it. In this case we’re better off using Column “C."

Note 4

Up to now we have been calculating feeder and service demands. Note 4 deals with branch circuits exclusively...

Table 220.55, Note 4: Branch-Circuit Load. It shall be permissible to calculate the branch-circuit load for one range in accordance with Table 220.55. The branch circuit load for one wall-mounted oven or one counter-mounted cooking unit shall be the nameplate rating of the appliance. 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.

There’s actually three parts to Note 4...

Part 1: Allows us to use Table 220-55 in calculating the branch circuit requirements for one range.

For example: A 12 kW range would be rated 8 kW according to Table 220.55. Converting 8 kW to amps...

Table 220.55, Note 4: Branch-Circuit Load. It shall be permissible to calculate the branch-circuit load for one range in accordance with Table 220.55. The branch circuit load for one wall-mounted oven or one counter-mounted cooking unit shall be the nameplate rating of the appliance. 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.

There’s actually three parts to Note 4...

Part 1: Allows us to use Table 220-55 in calculating the branch circuit requirements for one range.

For example: A 12 kW range would be rated 8 kW according to Table 220.55. Converting 8 kW to amps...

8,000 watts / 240 volts = 33.3 amps

Our branch circuit would then require #8 THW conductors and a 35 amp breaker.

Part 2: The branch circuit load for either one wall-mounted oven, or one counter-mounted cooking unit shall be the nameplate rating of the appliance. So, forget about using Table 220.55 for these guys.

Part 2: The branch circuit load for either one wall-mounted oven, or one counter-mounted cooking unit shall be the nameplate rating of the appliance. So, forget about using Table 220.55 for these guys.

Part 3: Now, if we had a situation where in one room (preferably the kitchen) we have one counter-mounted cooking unit and (up to) two wall-mounted ovens (all of which are on the same branch circuit), we could add together all of their nameplate ratings and treat them as one range. Then we could go back to "Part 1" and use Table 220.55 for the branch circuit requirements for one range. This looks like one of those kitchen remodeling jobs where they take out the old range and replace it with fancy new ovens and a cooktop.

Neutrals

Article 220.61(B)(1): For a feeder supplying household electric ranges, wall-mounted ovens, and counter-mounted cooking units, the neutral load shall be considered as 70% of the load on the feeder conductors (as determined by Table 220.55). A 70% reduction, for the neutral, more than covers the 120 volt components which include the clocks, timers and lights used in most ranges.

Note 5

Note 5 allows us to use Table 220.55 for household cooking appliances used in “school instructional programs.” This is the only exception to the residential use of Table 220.55.

For other than dwelling units, or commercial applications, Article 220.56 and Table 220.56 would have to be used.

*Table 220.55, Note 5: This table shall also apply to household cooking appliances rated over 1-3⁄4 kW and used in instructional programs.*For other than dwelling units, or commercial applications, Article 220.56 and Table 220.56 would have to be used.

Non-Residential (Commercial) Cooking Equipment

Article 220.56 covers non-residential, or commercial electric cooking equipment. In this situation, all kitchen related equipment would be included; ranges, ovens, dishwashers, booster heaters, water heaters, coffee pots, toasters, etc. would count as kitchen equipment. Air-conditioning, space-heating and ventilating equipment would not count.

However, in no case shall the feeder or service calculated load be less than the sum of the largest two kitchen equipment loads.

Table 220.56 replaces Table 220.55 for commercial appliances and is much easier to use.

*220.56 Kitchen Equipment - Other Than Dwelling Unit(s). It shall be permissible to calculate the load for commercial electric cooking equipment, dishwasher booster heaters, water heaters, and other kitchen equipment in accordance with Table 220.56. These demand factors shall be applied to all equipment that has either thermostatic control or intermittent use as kitchen equipment. These demand factors shall not apply to space-heating, ventilating, or air-conditioning equipment.*However, in no case shall the feeder or service calculated load be less than the sum of the largest two kitchen equipment loads.

Table 220.56 replaces Table 220.55 for commercial appliances and is much easier to use.

Keep in mind that the demanded load of all of the cooking equipment cannot exceed the sum of the largest two kitchen equipment loads. We’ll have to keep a look-out for that possibility.

Here are the steps:

(1) Total the number of cooking equipment loads.

(2) Total all of the nameplate ratings of all of the appliances.

(3) Find the demand factor in Table 220.56.

(4) Multiply the sum of all the appliances by the demand factor.

(5) Compare the demanded load to the sum of the largest two equipment loads.

For example, Say we have to find the feeder and service demand for the following commercial kitchen equipment loads...

1 Range at 16 kW

1 Oven at 10 kW

1 Dishwasher at 3 kW

1 Booster Heater at 3 kW

1 Coffee Pot at 2 kW

(1) Total the number of cooking appliances = 5

(2) Total the sum of all of the nameplate ratings = 34 kW

(3) Find the demand factor in Table 220.56 = 70%

(4) Multiply the sum by demand factor (34 kW x .7) = 23.8 kW

(5) Compare to largest two equipment loads (16 + 10 kW) = 26 kW

All that derating for nothing !

Here are the steps:

(1) Total the number of cooking equipment loads.

(2) Total all of the nameplate ratings of all of the appliances.

(3) Find the demand factor in Table 220.56.

(4) Multiply the sum of all the appliances by the demand factor.

(5) Compare the demanded load to the sum of the largest two equipment loads.

For example, Say we have to find the feeder and service demand for the following commercial kitchen equipment loads...

1 Range at 16 kW

1 Oven at 10 kW

1 Dishwasher at 3 kW

1 Booster Heater at 3 kW

1 Coffee Pot at 2 kW

(1) Total the number of cooking appliances = 5

(2) Total the sum of all of the nameplate ratings = 34 kW

(3) Find the demand factor in Table 220.56 = 70%

(4) Multiply the sum by demand factor (34 kW x .7) = 23.8 kW

(5) Compare to largest two equipment loads (16 + 10 kW) = 26 kW

All that derating for nothing !