Demand Factors for Motel Room Appliances

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powerfill

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I'm trying to find the demand factors that would be applied to small refrigerator, microwave oven, and small coffee pot when they are being added to existing motel rooms. I wouldn't think these would fall under cooking appliances. Here's the specs:
Refer: 150 Watts
Micro: 1000 Watts
Coffee Pot: 600 Watts
These would be added to 28 rooms - the refrigerators are turned off each time the room is vacated and are often never turned on. Micro & coffee pots are definately not continuous loads... So what demand factor can be applied in this situation ( per the NEC ) ??
 
Re: Demand Factors for Motel Room Appliances

I don't believe there is a demand factor provided for these appliances. 220.17 would not apply as these are not fastened in place appliances.

Are you providing new circuits for these loads? I would imagine that these appliances will simply be using the receptacles already in place. In that case, those receptacles are already figured into the general lighting load as computed from Table 22.3(A) as specified in 220.3(B)(10).
 
Re: Demand Factors for Motel Room Appliances

If all the motel is doing is adding equipment, and not having you install new branch circuits, then I would agree with Bryan. The loads are addressed within the existing service calculation.

But this seems an unusual situation. Are these 28 rooms already in place? If these are old rooms, and if they had a place in which a fridge can now be installed, then what have they been doing with that space? If they are adding 28 new rooms, then you are into 220.3(C). But that does not sound like the case here.

My problem is that 150 plus 1000 plus 600 times 28 units gives you 204 new amps on an existing 240 volt service. That is a lot of power.

How about trying 220.31(A), ?Optional Calculations for Additional Loads in an Existing Dwelling Unit??
 
Re: Demand Factors for Motel Room Appliances

Let me clarify a few items:

1. Yes the rooms are exisitng rooms.
2. No they have never had any convenience appliances in them before.
3. Yes, I will be adding a circuit for each room as the existing rooms are 2 rooms to a circuit.
4. These new circuits will go back to a new load center with a new feeder back to the main service. Main service is 120/208 3 Phase - 1000 Amp service - Electrical demand meter indicates a peak demand of only about 250 Amps

Like I indicated in my original post I didn't know what to apply either. Logic would tell you that there would be pretty minimal load at almost all hours of the day. The coffee pots might run for 15 minutes in the morning in various rooms at different times, and people certainly aren't going to nuke a Turkey in the micro for 2 hours (are they???) so the micro wave ovens would be run for a few minutes here or there, and the refrigerator loads are minimal and would all not be running at the same time.

So I just used the calculation for additional receptacles added to dwelling unit. Which gave me a reasonable feeder size. I figured I'd run a 100A sub feed over to power the new circuits.

I put in my agreement that the calculations were based on logic and what I felt was a reasonable solution and that they should consult with an electrical engineer if they were uncomfortable with my approach.

By the way. This forum is a great. It's good to be able to get input from others. Thanks to Mike Holt's instruction and all he does for the electrical trades.

Dan
 
Re: Demand Factors for Motel Room Appliances

I would be inclined to run a new 20A circuit to each room for these additional appliances and call it good.

Its not likely that any substantial number of these things will ever be on at the same time. You might want to make a good guess about it though just to satisfy your own concerns.

This is my chain of thought.

Coffee pot - 600W but probably only a few on simultaneously.

Refrig - typically run only for a few minutes at a time, not a big load anyway.

Microwave - something that only runs a minute or two at a time.

My back of the envelope calculations would go something like this.

worst case is first thing in the morning with all the rooms in use.

1/4 of the coffee pots are on
1/2 of the fridges are rnning
1/10 of the microwaves in use

likely max power ever used is under 10Kw.

while its not an "official" calculation it certainly gives you an idea what you are likely to actually see in real life.
 
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