Apartment Building House Loads Demand
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DrSparks
The Everlasting Know-it-all!
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- Madison, WI, USA
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- Master Electrician and General Contractor
Art. 220 p. III. for special loads references other parts of the code (e.g. elevator). For general lighting, you would use table 220.12. So for corridors, halls and stairways you'd calculate 1/2 VA/Sq ft. For storage spaces you'd calculate 1/4 VA / Sq ft, etc. Electric space heaters would be 100% continuous. No VA requirement for "convenience receptacles " but would be for a receptacle serving a specific load, like a sump pump.
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How can there be no requirement for VA/sq ft for receptacles? Could I use 1VA/sqft for receptacles if I wanted to? Is it a judgment call on what VA/sqft for receptacles is?
DrSparks
The Everlasting Know-it-all!
- Location
- Madison, WI, USA
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- Master Electrician and General Contractor
No. In residential, any receptacles that are not part of a special circuit, like the kitchen appliance circuits, laundry, bathroom GFI, are considered part of the general lighting circuits. So the VA/Sq ft applies to lighting and receptacles. You can have unlimited receptacles on these circuits. For lighting, you are limited by the maximum wattage rating ofbthe fixtures.
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Yea but but I’m talking about public light and power AKA house loads, not dwelling units.
Also, do you count motors at 100% demand when doing house loads?
MyCleveland
Senior Member
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- Cleveland, Ohio
Bad advice I believe...public areas of an apartment complex do not fall under rules for the actual apartments themselves.
MyCleveland
Senior Member
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- Cleveland, Ohio
Look over table 220.12 again.
Mptors....see 220.14C, probably should be reading all of 220.14 a few times over.
Do your apartment loads allow you to use 220.84 ?
DrSparks
The Everlasting Know-it-all!
- Location
- Madison, WI, USA
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- Master Electrician and General Contractor
Right. That's why I advised looking at 220.12. There are specific VA/sq ft. rules for different areas.
Can't use 220.84 because there are gas ranges. Also 220.14C is not clear because those articles mentioned don't tell you what demand to do. Are motors considered 100% demand?
MyCleveland
Senior Member
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- Cleveland, Ohio
I am sorry, I struggled to follow.
How are the receptacles covered in the lighting load ?
Post 4: what cut’s can have unlimited receptacles?
MyCleveland
Senior Member
- Location
- Cleveland, Ohio
220.84…you can use if it benefits you. I am very sure your gear size will fall.
Read the exception that follows 220.84 A 2.
430.24 - follow 1-4. If you are looking for some multiplier that lets you reduce your total motor or hvac load by some percentage…it does not exist.
If I do the exception, then all the apartment services will be too high which results larger wire and overcurrent protection because of adding the 8kw for range
MyCleveland
Senior Member
- Location
- Cleveland, Ohio
What does the first sentence of 220.84 say…
This is about sizing feeders to meter stacks and the overall service calc for the building.
What are you using for calculating these values ? 220 part 3 or part 4 ?
I believe you stated you had 140 apartments.
If you have a total apartment load calculated…let’s say 20kVa per unit x 140 = 2800kVA. Using table 220.84 let’s you knock that 2800 x .23 down to 644kVA.
Adding the 8kW per unit is just for the feeder and service calls to mimic them actually having an electric range which then gives you access to table 220.84.
MyCleveland
Senior Member
- Location
- Cleveland, Ohio
I forgot to ask, but you must also meet criteria of 220.84 A 1…meaning ALL apartment loads are served by apartment panel. In all of these threadsI don’t believe you ever mentioned have systems or hot water.
I got to be the dumbest engineer out there lol! I can't believe I didn't realize this the key sentence...
For each individual apartments I used part 3 standard method to calculate my demand because of gas ranges, but I'm gonna use optional method to calculate the overall demand and mimic the 8kw range per unit to get the lower result.
Could you clarify what that condition actually means?
In your example you didn’t add the 8kva range per unit, shouldn’t it be 28kva per unit not 20kva like you said, am I missing something?
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MyCleveland
Senior Member
- Location
- Cleveland, Ohio
auto correct is killing me…will have to pay better attention.
MyCleveland
Senior Member
- Location
- Cleveland, Ohio
Everything powered within the apartment, the source must be the apartment panel.
The 20kVA number was just a number…assumed the range load was already added in.
It was just to show you the value of gaining access to table 220.84.
Hot water is supplied by the building panel.
Also, I am getting a higher total demand doing the optional method… is that normal?
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