Existing loads

Status
Not open for further replies.
S

Sparky5150

Member
Once a 1200 amp service has been metered for 30 days and is determined to have 1100 peak amps, can 100 amps be added to it if the service equipment and feeders is 100% rated?

Or do we need to do the 220-87 calc regardless?

Thanx!

Sparx :)
 
I believe not. I think you need to add 25% to the measured load, then add the new load, and still be under the equipment rating. So you need another solution. Perhaps it is time to talk to the owner about upgrading the service.
 
I think your missing 220.87(2). Your install has to comply with the exception to (1), and also (2) and (3).
 
Sparky5150 said:
Or do we need to do the 220-87 calc regardless?
Click to expand...
Rereading this portion of your question now leads me to believe you already knew about the section that Chris and I just talked about. So perhaps my answer should have been that you do need to do that calculation, and the owner is not going to like its result.

Good luck with this one.
 
Apart from any code violation, I would say that no an extra 100 amps of load can not be added.

How do you know that the service is not already loaded to 1,200 amps or more at times ?
IMHO 30 days is not long enough for data gathering, a greater load could easily occur at some other time of year.

If data logging for a whole year showed the load never exceeding 1,100 amps, then an additional 100 amps could in practice probably be added OK.
Though it might still violate code.
 
Status
Not open for further replies.
Top