Apartment Sub-Panel Size

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krmelectricbwm

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Hello everyone,

I am supposed to start a second floor apartment renovation soon for a customer/colleauge. It will be a full gut job with all new wiring, boxes, ect. The apartment's distribution is currently provided by a 50 Amp Murray sub-panel inside the unit supplied by a NM sheathed copper cable from a FPE panel in the basement. I intend to replace the panel with a newer Cutler Hammer unit. However, the customer indicated that he also wants to add a rooftop central air conditioner unit and a unitized/stackable washer/dryer. I told him that I could not install both from the sub-panel due to the 30 Amp 240 Volt load required for each unit. Am I correct about this situation or is there some de-rating factor that I am missing that will allow such an installation and still work safely?
 
Re: Apartment Sub-Panel Size

In my opinion, you need to perform a basic load calculation to determine if the additional loads are within the capacity of the existing installation. I would guess that it will not be. Considering this is a complete renovaton job, you will have to provide all required circuits for loads as specified in Article 220. I doubt you will get by with anything less than at least a 60A supply if not 100A.

I hope its the FPE panel that you plan on replacing.
 
Re: Apartment Sub-Panel Size

Thanks for your speedy reply Bryan,

Unfortunately I haven't convinced him to address the Federals sitting in the basement yet. I felt that the existing feed was sufficient enough for the apartment loads without doing a calculations until he hit me with the desired washer/dryer and A/C unit. I based my price on a 120 Volt receptacle for gas operated laundry equipment and told him the situation in the basement should be on the top of his priority list.
 
Re: Apartment Sub-Panel Size

I'm learing, this is a good forum. I had to look up Federal Pacific Electric (FPE panel) it Federal Pacific Electric panel. from what look up it not a good panel.
That these panels pose a latent threat and could be a hazard. The circuit breakers may fail to trip in the case of an overload or short-circuit. A circuit breaker that fails to trip could cause a fire or personal injury.

The problem with these panels is that some double pole 220volt circuit breakers and some single pole 120volt circuit breakers may not work or trip causing a fire
 
Re: Apartment Sub-Panel Size

Here's an update,

I calculated the load as suggested and explained thorougly by members of this fine forum. Thank you all!!! A 60 Amp feed would be the minimum size that I could supply the apartment with and that still would not be enough to handle the demand load of the electric dryer with the other fixed loads and central A/C unit. It looks like I will be walking away from this job anyhow due the price I quoted the customer and what he believes it should cost. Oh well, every bump in the road is an opportunity to learn something new.
 
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