calculating additional loads on service

[jcole]

Whats up guys and gal? Have a project where I am adding a full living quarters (kit,bath,living room, bedroom,laundry,central air, ) to a doctors office. The doctors office was considered a one family dwelling back 30 or so years ago before it was converted. How would you guys figure out if an additional service or service upgrade is needed? Would you treat the entire building a dwelling and use 220.83 or seperate the existing load as non-dwelling per art. 220 and the new addition as dwelling and use 220.80 and add the 2 calculated loads together. Need to do a correct service load calculation to justify additonal service. Thanks in advance for all replies.

 

[kkwong]

Not having my NEC handy, I would think you would calc out the load in the residence and then add the two loads together since you have two different occupancies. Just my thoughts...

 

[Jomaul]

I would think it depends on the type of construction. if there is a fire wall that will seperate the 2 then you could calaculate each load then add them together, but if there is no fire wall then the building would be classified 1 commercial structure and you would have to figure the load accordingly as per 220.16 B

 

[jcole]

Just wanted to add that the areas are not separated by a fire wall or ceiling. I added this thought because the fact they are not keeps me from adding an additional service just for dwelling area per 230.2. I think? Anymore thoughts would be appreciated.

 

[satcom]

Just wanted to add that the areas are not separated by a fire wall or ceiling. I added this thought because the fact they are not keeps me from adding an additional service just for dwelling area per 230.2. I think? Anymore thoughts would be appreciated.

You may want to check with the city, and see how they have the building classified, before you proceed with any work, do they have a set of plans approved for the addition? will the doctors office, and the appartment be on one meter? and just a quick check with your AHJ might help resolve some of the issues.

 

[haskindm]

You would probably not be able to add an additional SERVICE unless the occupancies are separated by fire walls, but you could add an additional meter and each occupancy could have its own distribution panel. Don't get panels and meters confused with services. Each occupancy would be calculated using article 220 according to its use and then the occupancies would be added together to get your total service load.

 

[cowboyjwc]

Here we don't allow mixed use like that. It's either residential or it's commercial, so how it's zoned would then decide on how you do your load calc.

 

[JohnJ0906]

You may want to check with the city, and see how they have the building classified, before you proceed with any work, do they have a set of plans approved for the addition? will the doctors office, and the appartment be on one meter? and just a quick check with your AHJ might help resolve some of the issues.

I think this would be your best bet.