I recently took a test that required that the service loads be calculated without house loads. I cannot find what is meant by the term "house loads" and this obviously affects the total service load. Any ideas about what constitutes a house load or a reference book that might define them?
Defining House Loads
- Thread starter jimegg
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- Lockport, IL
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- Semi-Retired Electrical Engineer
Re: Defining House Loads
I would add the elevators and the building owner's offices (e.g., the rental office). Put another way, you would install a separate meter for each tenant, and a separate meter for electricity used by the owner/property manager.
I would add the elevators and the building owner's offices (e.g., the rental office). Put another way, you would install a separate meter for each tenant, and a separate meter for electricity used by the owner/property manager.
Re: Defining House Loads
So essentially house loads are common areas in multi-family dwellings. Now what if this term were to apply to a duplex or single family dwelling unit? Does it mean laundry loads or small appliance branch circuits?
A duplex is a two-family dwelling unit so loads are calculated using dwelling unit calculation methods, not multi-family calculations, correct?
I find this test especially tough due to the time restraints.
So essentially house loads are common areas in multi-family dwellings. Now what if this term were to apply to a duplex or single family dwelling unit? Does it mean laundry loads or small appliance branch circuits?
A duplex is a two-family dwelling unit so loads are calculated using dwelling unit calculation methods, not multi-family calculations, correct?
I find this test especially tough due to the time restraints.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Defining House Loads
In the context of the types of exam questions you are describing, the phrase "house loads" has no meaning unless you have more than one dwelling unit at a facility, and unless the owner gets a bill for an electric meter that is different from the electric meters associated with the residents. So it does not apply to a single-family dwelling. Also, it would probably not apply to a duplex, because a duplex probably only has two meters (one for each resident), without a third meter for the owner/property manager.
In the context of the types of exam questions you are describing, the phrase "house loads" has no meaning unless you have more than one dwelling unit at a facility, and unless the owner gets a bill for an electric meter that is different from the electric meters associated with the residents. So it does not apply to a single-family dwelling. Also, it would probably not apply to a duplex, because a duplex probably only has two meters (one for each resident), without a third meter for the owner/property manager.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Defining House Loads
No. For an apartment complex with a common laundry area, the laundry loads would be on the meter for which the owner pays the bill. That counts as a ?house load.? But the laundry circuit and the small appliance circuit that are required by NEC Article 210.11(C) are not ?house loads.? Do not allow the word ?house? to confuse you. It is used in the same context as when they say of casino?s that ?the house always wins.? In that example, the casino itself is the ?house.?
A duplex is a multi-family dwelling unit. Therefore, the service calculation for the duplex as a whole is done as a multi-family dwelling unit. However, the feeder to either of the two units is calculated for a single-family dwelling unit.
Re: Defining House Loads
Thanks for your prompt reply. I had thought of the casino parallel to the "house" also, and it makes sense but I'm not sure if the test question was on multi-family dwelling units or single dwelling units.
I'll re-read the code, but I thought that a dwelling unit was defined as one or two dwelling units and three or more are considered multi-family.
Thanks for your prompt reply. I had thought of the casino parallel to the "house" also, and it makes sense but I'm not sure if the test question was on multi-family dwelling units or single dwelling units.
I'll re-read the code, but I thought that a dwelling unit was defined as one or two dwelling units and three or more are considered multi-family.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Defining House Loads
Article 100 defines one-family, two-family, and multi-family dwelling units. The thing to keep straight is whether the test question is asking about a single dwelling unit, even if it is part of a complex that has many dwelling units. In other words, are they asking about one apartment or about the apartment building as a whole?
One example of how this can get tricky is doing an optional method for an apartment building. For the overall service calculation, you get to count all the dryers and all the ranges in the entire complex. That way, you get to use the smaller demand factors from Tables 220.18 and 220.19. On the other hand, if they are talking about a single apartment, then you have to use the demand factor that is associated with 1 dryer or with 1 range.
Article 100 defines one-family, two-family, and multi-family dwelling units. The thing to keep straight is whether the test question is asking about a single dwelling unit, even if it is part of a complex that has many dwelling units. In other words, are they asking about one apartment or about the apartment building as a whole?
One example of how this can get tricky is doing an optional method for an apartment building. For the overall service calculation, you get to count all the dryers and all the ranges in the entire complex. That way, you get to use the smaller demand factors from Tables 220.18 and 220.19. On the other hand, if they are talking about a single apartment, then you have to use the demand factor that is associated with 1 dryer or with 1 range.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Defining House Loads
Let me say a few things about language.
A common trap that exists throughout the English-speaking world is the confusion that arises when conversational terms are intermixed with technical or precisely-defined terms. The term ?duplex? is a common enough English term. But as far as the NEC is concerned it does not exist, or at least not in the context of a living space. The NEC only uses the word ?duplex? in combination with the word ?receptacle.?
So you need to treat the question as having used the word ?duplex? as a conversational term, and not as a technical term. You need to interpret that term as meaning what Article 100 defines as a ?dwelling unit, two family.? That is the technical term that the question should have used.
But keep your focus on one key aspect of the question (as I had mentioned before): Are they asking about one of the two sides of the duplex, or are they asking about the building as a whole?
Let me say a few things about language.
A common trap that exists throughout the English-speaking world is the confusion that arises when conversational terms are intermixed with technical or precisely-defined terms. The term ?duplex? is a common enough English term. But as far as the NEC is concerned it does not exist, or at least not in the context of a living space. The NEC only uses the word ?duplex? in combination with the word ?receptacle.?
So you need to treat the question as having used the word ?duplex? as a conversational term, and not as a technical term. You need to interpret that term as meaning what Article 100 defines as a ?dwelling unit, two family.? That is the technical term that the question should have used.
But keep your focus on one key aspect of the question (as I had mentioned before): Are they asking about one of the two sides of the duplex, or are they asking about the building as a whole?
Re: Defining House Loads
They are talking about the service demand for a duplex (dictionary definition: 2)and since there are multiple appliances connected to the same load, I take from the code that I can use the demand factors to calculate the service demand for multiple appliances, heaters, etc. and I think that this is where I went wrong, I was just not familiar enough with the code. Are air conditioners always calculated as air conditioners and not appliances, especially 120-volt single phase units? And do you need to use the entire demand load of multiple air conditionere if not considered appliances?
They are talking about the service demand for a duplex (dictionary definition: 2)and since there are multiple appliances connected to the same load, I take from the code that I can use the demand factors to calculate the service demand for multiple appliances, heaters, etc. and I think that this is where I went wrong, I was just not familiar enough with the code. Are air conditioners always calculated as air conditioners and not appliances, especially 120-volt single phase units? And do you need to use the entire demand load of multiple air conditionere if not considered appliances?
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: Defining House Loads
Air conditioners are not appliances, and there are no special demand factors that apply to them. You count them all. But make sure you compare the air conditioning load to the heating load. In most cases, you don't have to count both, but rather count only the larger of the two.
Air conditioners are not appliances, and there are no special demand factors that apply to them. You count them all. But make sure you compare the air conditioning load to the heating load. In most cases, you don't have to count both, but rather count only the larger of the two.
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