Electric oven multi unit residential

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nickelec

Senior Member
Location
US
Maybe you guys can give me a little help here.

I have a customer it's an existing multi-unit residential building I think that's about 10 units being fed with 400 amps for five apartments and 400 amps for the other five apartments..

They currently have gas cooking and heating. Where do I begin to see if the servic size is sufficient and also the feeder from the basement to the apartment.

They're looking for me to give them an idea of what size electric range they should purchase and if they have the capacity to do so

Sent from my SM-S926U using Tapatalk
 
Table 220.55 gives you demand loads for cooking appliances.

Simple range of no more than 12 kW rating would normally be considered 8 kW load for the branch circuit calculation.

If you have five of them on a feeder/service the total demand to use for load calculations would be 20 kW.

You need to factor in what is there for existing load as well to know if you have capacity to add these appliances to what is there.
 
nickelec said:
Maybe you guys can give me a little help here.

I have a customer it's an existing multi-unit residential building I think that's about 10 units being fed with 400 amps for five apartments and 400 amps for the other five apartments..

They currently have gas cooking and heating. Where do I begin to see if the servic size is sufficient and also the feeder from the basement to the apartment.

They're looking for me to give them an idea of what size electric range they should purchase and if they have the capacity to do so

Sent from my SM-S926U using Tapatalk
Click to expand...
2023 NEC
Check out Part IV Section 220.80 thru 220.83 (B)
Section 220.84 Multifamily Dwelling through 220.87
TX+MASTER#4544
 
nickelec said:
Maybe you guys can give me a little help here.

I have a customer it's an existing multi-unit residential building I think that's about 10 units being fed with 400 amps for five apartments and 400 amps for the other five apartments..

They currently have gas cooking and heating. Where do I begin to see if the servic size is sufficient and also the feeder from the basement to the apartment.
Click to expand...
Assuming your building(s) where eligible for the OPTIONAL method calc and you are at 240V-1P...
400A for 5 apartments seems large.
400 x 240 = 96000VA
Using table 220.84 in reverse means your original 5 apt total load was 96000/0.45 = ~~ 213kVA.
213k / 5 = 42600VA avg capacity of each apartment or ~~ 177A @ 240V.
Seems high doesn't it. Maybe these are some very large apartments, but I have never designed one that large.

Just start with the square footages, appliance lists and HVAC loads and work through the math as others have stated, but I believe you will have the service CAPACITY, but maybe not the apartment capacity. You will need to check each individual unit feeder in your calculations too.
 
MyCleveland said:
Assuming your building(s) where eligible for the OPTIONAL method calc and you are at 240V-1P...
400A for 5 apartments seems large.
400 x 240 = 96000VA
Using table 220.84 in reverse means your original 5 apt total load was 96000/0.45 = ~~ 213kVA.
213k / 5 = 42600VA avg capacity of each apartment or ~~ 177A @ 240V.
Seems high doesn't it. Maybe these are some very large apartments, but I have never designed one that large.

Just start with the square footages, appliance lists and HVAC loads and work through the math as others have stated, but I believe you will have the service CAPACITY, but maybe not the apartment capacity. You will need to check each individual unit feeder in your calculations too.
Click to expand...
I do agree on the service capacity, 5 units with gas heat can be pretty large units before you run into troubles unless there is some other loads not so common in individual units of multifamily.

Tankless electric water heating could possibly kill your capacity I guess if there is much of that involved.
 
MyCleveland said:
Assuming your building(s) where eligible for the OPTIONAL method calc and you are at 240V-1P...
400A for 5 apartments seems large.
400 x 240 = 96000VA
Using table 220.84 in reverse means your original 5 apt total load was 96000/0.45 = ~~ 213kVA.
213k / 5 = 42600VA avg capacity of each apartment or ~~ 177A @ 240V.
Seems high doesn't it. Maybe these are some very large apartments, but I have never designed one that large.

Just start with the square footages, appliance lists and HVAC loads and work through the math as others have stated, but I believe you will have the service CAPACITY, but maybe not the apartment capacity. You will need to check each individual unit feeder in your calculations too.
Click to expand...
2023 NEC
Did you apply the demand factors found in T. 220.84(B) for the number of dwelling units?
I don't see it.
TX+MASTER#4544
 
nickelec said:
Maybe you guys can give me a little help here.

I have a customer it's an existing multi-unit residential building I think that's about 10 units being fed with 400 amps for five apartments and 400 amps for the other five apartments..

They currently have gas cooking and heating. Where do I begin to see if the servic size is sufficient and also the feeder from the basement to the apartment.

They're looking for me to give them an idea of what size electric range they should purchase and if they have the capacity to do so

Sent from my SM-S926U using Tapatalk
Click to expand...
Here is a video on Multifamily calcs that may be helpful. There are other videos (like on Range calcs, etc.) in this same series, also. I've found them to be useful.
 
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