What is a Microwave?

[charlie b]

I am designing a 150 room dormitory building. Each room will have two beds, two closets, and a shared bathroom. Each room is going to have a microwave oven to which I plan to assign a load of 1kW. I am looking for a way to not have to include 150kW just for microwaves in the service load. At the present stage of the design, we are treating the outlets for microwaves as being just a receptacle (but with 1000 VA instead of 180 VA), and including them in the “50% after the first 10K” demand factor. But whether we have other options depends on how we treat the microwave.

1. Is it, for example, “permanent provisions for cooking,” in the context of the definition of “dwelling unit”?
2. Is it rather “kitchen equipment,” in the context of 220.56?
3. Would it disqualify us from using Table 220.42 because our dorms are not “without provisions for cooking by tenants”?

I prefer the answer to #1 to be “no,” because I don’t want to call this building a multi-family dwelling unit. I might be able to justify a “yes” to #2 by saying this is “other kitchen equipment” that has intermittent use. But that gives me no better than a 65% demand factor. I can get a lower calculated load if the answer to #3 is “no.” One key difference between #1 and #3 is the word “permanent.” This word appears in the definition of dwelling unit, but not in Table 220.42.

But here is my real dilemma. That table is for lighting, but we can use it for receptacles that we calculate using 220.14(I). That article says “not less than 180 VA,” and 1000 VA is certainly not less than 180. But if I know that the intent is to plug a microwave into a certain receptacle, does that put me into 220.14(A)? If so, then I think I cannot use the demand factors in Table 220.42.

Comments?

 

[Dennis Alwon]

If there is no kitchen, I don't believe a mw is considered a permanent means for cooking especially since, I assume, it is not built in, then I don't see why it cannot be used in the demand tables. I think that you have covered yourself well by using 1000 watts and since they will be plugged into standard wall outlets it shouldn't be an issue.

Now if there is a kitchen, per se, then I believe you could just use the 2 small appliance branch circuit and be done with it.

 

[sameguy]

Agree with no kitchen on plans than wave is just a load.

 

[petersonra]

Dwelling Unit. A single unit, providing complete and independent
living facilities for one or more persons, including
permanent provisions for living, sleeping, cooking, and sanitation.

Most dorm rooms do not qualify as a dwelling unit under this definition as the bathrooms are often separate and there are usually no "living" provisions as part of the dorm room itself.

In your case, having two rooms share a bathroom means the sanitation facilities are not part of the unit, thus it is not a dwelling unit.

Personally, I think if the microwave is part of the dorm room equipment it is pretty much permanent.

 

[JFletcher]

Are they built in, or just going to be on the countertop?

Never understood why microwaves and garbage disposals even need to be figured into load calculations. I think the longest I have ever run a microwave was 8 minutes to cook a baked potato. Usually runs 3 to 4 minutes then off for a minute while you stir your food. And garbage disposals, what, about 8 seconds, perhaps two at full load?

If you don't want to include them, simply add a countertop version after the units are built. You would not have to consider them as a load since at that point they do not exist.

 

[charlie b]

There are kitchens, with ranges, on two of the floors. But in the sleeping rooms (i.e., 2 beds with shared bathroom) the microwaves are not fixed in place. At present, the plans says to provide a dedicated receptacle for a countertop microwave. That wording might put me into 220.14(A). I am considering removing that text. I would like to use Table 220.42. But the words ". . . apartment houses without provisions for cooking by tenants" concern me. Regardless of whether the provision is permanent, and regardless of whether we can call it "kitchen equipment," a tenant can use a microwave to cook food.

Regarding the status of the units (i.e., dwelling unit or not), you enter from the corridor into a room that has 2 beds (certainly "provisions for sleeping") and 2 desks with a TV above them (possibly "provisions for living"). Go through a door and you have access to 2 closets. While in that area, go through another door to a toilet and a shower (certainly "provisions for sanitation"). I am calling this a "non-dwelling unit" by virtue of the microwave not being a "permanent" provision for cooking.

 

[petersonra]

There are kitchens, with ranges, on two of the floors. But in the sleeping rooms (i.e., 2 beds with shared bathroom) the microwaves are not fixed in place. At present, the plans says to provide a dedicated receptacle for a countertop microwave. That wording might put me into 220.14(A). I am considering removing that text. I would like to use Table 220.42. But the words ". . . apartment houses without provisions for cooking by tenants" concern me. Regardless of whether the provision is permanent, and regardless of whether we can call it "kitchen equipment," a tenant can use a microwave to cook food.

Regarding the status of the units (i.e., dwelling unit or not), you enter from the corridor into a room that has 2 beds (certainly "provisions for sleeping") and 2 desks with a TV above them (possibly "provisions for living"). Go through a door and you have access to 2 closets. While in that area, go through another door to a toilet and a shower (certainly "provisions for sanitation"). I am calling this a "non-dwelling unit" by virtue of the microwave not being a "permanent" provision for cooking.

read carefully the definition of "dwelling unit". It is not a dwelling unit if the bathroom is not part of the unit since it is not "independent".

 

[Strathead]

I am designing a 150 room dormitory building. Each room will have two beds, two closets, and a shared bathroom. Each room is going to have a microwave oven to which I plan to assign a load of 1kW. I am looking for a way to not have to include 150kW just for microwaves in the service load. At the present stage of the design, we are treating the outlets for microwaves as being just a receptacle (but with 1000 VA instead of 180 VA), and including them in the “50% after the first 10K” demand factor. But whether we have other options depends on how we treat the microwave.

1. Is it, for example, “permanent provisions for cooking,” in the context of the definition of “dwelling unit”?
2. Is it rather “kitchen equipment,” in the context of 220.56?
3. Would it disqualify us from using Table 220.42 because our dorms are not “without provisions for cooking by tenants”?

I prefer the answer to #1 to be “no,” because I don’t want to call this building a multi-family dwelling unit. I might be able to justify a “yes” to #2 by saying this is “other kitchen equipment” that has intermittent use. But that gives me no better than a 65% demand factor. I can get a lower calculated load if the answer to #3 is “no.” One key difference between #1 and #3 is the word “permanent.” This word appears in the definition of dwelling unit, but not in Table 220.42.

But here is my real dilemma. That table is for lighting, but we can use it for receptacles that we calculate using 220.14(I). That article says “not less than 180 VA,” and 1000 VA is certainly not less than 180. But if I know that the intent is to plug a microwave into a certain receptacle, does that put me into 220.14(A)? If so, then I think I cannot use the demand factors in Table 220.42.

Comments?

This is solely an opinion not presented as an expert interpretation. I feel very strongly that 220.56 applies. I also feel that 220.42 can be used, but I can see where an AHJ might object. Honestly, I am not sure of the wording of the table. Hotels and motels, including apartment houses without provision for cooking by tenants. Given the comma and the phrasing I would argue that it doesn't say "Hotels and motels without provision for cooking by tenants." At the same time it also doesn't say dormitory. Either way, I don't feel that any part of 220.56 allows or disavows 220.42 and I feel it is quite clearly able to be utilized. A microwave is not considered "provisions for cooking by tenants." So whether you can use 220.42 would be strictly up to the AHJ. Were I one, I would be fine with it.

The irony is that as much as we get hung up on the load calculations, and it is a solid code, the real question is whether or not the service and feeders are large enough. At the current time with the advent of LED lighting, very strict and prevalent energy codes, and a code that hasn't made a single adjustment in the load calculations to account for them, I would worry very little about using both 220.42 and 22.56 to reduce the calculated load.

 

[petersonra]

A microwave is not considered "provisions for cooking by tenants."

it is certainly there for cooking purposes. Are you trying to claim that it is not there for the tenants? Or that the occupants are not tenants?

 

[gadfly56]

Most dorm rooms do not qualify as a dwelling unit under this definition as the bathrooms are often separate and there are usually no "living" provisions as part of the dorm room itself.

In your case, having two rooms share a bathroom means the sanitation facilities are not part of the unit, thus it is not a dwelling unit.

Personally, I think if the microwave is part of the dorm room equipment it is pretty much permanent.

Really?? I'll have to have a chat with the tax assessor since there is only one bathroom shared by three bedrooms in the house. Who knew I didn't have a dwelling unit? :roll:

 

[gadfly56]

it is certainly there for cooking purposes. Are you trying to claim that it is not there for the tenants? Or that the occupants are not tenants?

If you can unplug it, pick it up and carry it out, it's not "permanent".

 

[charlie b]

read carefully the definition of "dwelling unit". It is not a dwelling unit if the bathroom is not part of the unit since it is not "independent".

Perhaps I wasn't clear in my description. Two students will share a room that has 2 beds and 2 desks. They also share a bathroom that is only accessible to those two students. There are 150 "dorm units," and each has its own bathroom. So that would not disqualify them from being dwelling units. That said, I want to disqualify them from being dwelling units, and I am using the notion that a microwave is not a permanent provision in order to get there.

 

[gadfly56]

Perhaps I wasn't clear in my description. Two students will share a room that has 2 beds and 2 desks. They also share a bathroom that is only accessible to those two students. There are 150 "dorm units," and each has its own bathroom. So that would not disqualify them from being dwelling units. That said, I want to disqualify them from being dwelling units, and I am using the notion that a microwave is not a permanent provision in order to get there.

Is there a sink and refrigerator on the plans? That might tip things toward "dwelling unit", and their lack might tip things the other way.

 

[charlie b]

I feel very strongly that 220.56 applies.

I agree, but perhaps not strongly. However, that would not help me. The designer who did the load calculation applied the “50% over 10K” rule. 220.56 would give me a demand factor no lower than 65%. 220.42 is a better deal, if I can use it.

I also feel that 220.42 can be used, but I can see where an AHJ might object. Honestly, I am not sure of the wording of the table. Hotels and motels, including apartment houses without provision for cooking by tenants. Given the comma and the phrasing I would argue that it doesn't say "Hotels and motels without provision for cooking by tenants."

I noticed the placement of the comma as well. This dorm building is closer to a hotel than anything else. If I can use the comma placement as justification of saying I have a hotel and the ability of the tenant to cook anything is irrelevant, then I can save about 50KW on the overall load calculation.

A microwave is not considered "provisions for cooking by tenants."

Let me repeat that this article does not include the word “permanent,” in the phrase “provision for cooking.”

So whether you can use 220.42 would be strictly up to the AHJ.

Dis bein govmt work. We don’t gots no AHJ. :happyno:

 

[charlie b]

Is there a sink and refrigerator on the plans? That might tip things toward "dwelling unit", and their lack might tip things the other way.

Bathroom sink, yes. Kitchen sink or fridge, no.

 

[petersonra]

If you can unplug it, pick it up and carry it out, it's not "permanent".

So a dishwasher is not permanent? Or a range? Or a disposal?

By that definition almost nothing would be permanent.

 

[gadfly56]

So a dishwasher is not permanent? Or a range? Or a disposal?

By that definition almost nothing would be permanent.

In my experience, dishwashers are hard wired and you have to unscrew the retainer plate and wiggle the unit out to disconnect them. It's permanent. The range, likewise, with the addition of hard-piped gas. The disposal is bolted onto the bottom of the sink. It's permanent. None of these things are going out the door under your arm.

 

[petersonra]

Dis bein govmt work. We don’t gots no AHJ. :happyno:

I guarantee there is an AHJ. It is just not a local inspector.

In any case, I'd be inclined to take the 50 kW hit. It is not going to change much in the price of a 300 bed dormitory. Chances are people are going to bring in all kinds of electric appliances from popcorn poppers to hot plates to coffee makers to electric heaters. Better to have more juice available than less.

 

[gadfly56]

Bathroom sink, yes. Kitchen sink or fridge, no.

Can you post a screen cap of a typical suite?

 

[petersonra]

In my experience, dishwashers are hard wired and you have to unscrew the retainer plate and wiggle the unit out to disconnect them. It's permanent. The range, likewise, with the addition of hard-piped gas. The disposal is bolted onto the bottom of the sink. It's permanent. None of these things are going out the door under your arm.

so it's permanent if you have to use a tool to remove it? where is that in the code?