Service loads

[Mr 3phase]

I am currently dealing with a customer who is renting one unit of a three unit dwelling. The main service disconnect is a 200 amp breaker. One unit has a 100 amp subpanel, the remaining two are 50 amperes each. My customer is the 100 ampere panel. She needs to add a 60 ampere 2 pole breaker to her panel for an xray machine. My questions are:
1) Is there anything in the codebook that allows for me use a 'lower demand factor' overall and increase her disconnect breaker to her subpanel to 125 amperes?
2) Is there a limit as to the largest size breaker I may install in this subpanel...can I legally and safely install a 60 ampere breaker in this panel?

I have read and re read the codebook on Services, Panelboards, Feeders, and Branchcircuits. I cannot find anything to address this matter. Help, and guidance is appreciated.

 

[bphgravity]

X-ray machine in a dweling unit? That's a big red flag...

1. Yes. Perform a load calculation to determine if an increase in serivce size is needed, and if not, you can increase your feeder to supply whatever new loads you are adding.

2. No. There is no limit to the size of overcurrent devices installed in a panel as long as you have not violated the manufactuer's labeling and instructions. A 60A would must likely not be an issue.

I hope you are first applying for a permit and consulting the local AHJ in regard to this issue...

 

[mdshunk]

On a side note, it is quite normal for a tenant of a multi-unit building to have special power requirements that exceed what exists in their suite, and sometimes even what exists to the building. In these cases, they're faced with moving or upgrading as necessary (at their expense). This can get touchy when trying to coordinate the shutdown. I have one customer (Italian restaurant) who has been waiting 4 months now for the appointed time that we can kill the service to do some work for them.