Residential Wiring "Real World" Practices and NEC calculations

[new_ee]

Is a refrigerator (a standard kitchen one) receptacle usually on its own circuit? Or is it connected to the counter top receptacle circuits (i.e. small appliance branch circuits)?

I usually assume the refrigerator load is included in the two 1500A small appliance branch circuits for my calculations. I also do the same with microwaves.

I use 220.30 (the optional method) to do my calcs. 220.30 (B) (3) has me wondering. It says "... the nameplate rating of all appliances that are fastened in place, permanetly connected, or located to be on a specific circuit..." need to be included in the calcs.

If thats the case, and I connect the refrigerator to its own circuit, then do I now need to include it in my calcs? But if its on the same circuit the counter top receptacles then I don't have to include it in the calcs?

I usually put the dishwasher and disposal on their own seperate circuits and I include them seperately in my calcs.

Another question I have is about the HVAC loads. Assuming the residential design work I do has a heat pump split system with an air handling unit (usually w/aux. electric heat) and an outdoor condensing unit. I have been including the loads from both the AHU and the CU at 100% in my calcs. I'm not sure that this is right. I'm not sure about the operation of the split system and whether both the AHU and the CU will operate simultaneously.

 

[new_ee]

Also I have one more question. I've seen a high end condo unit that had enough kitchen counter top space to require in upwards of 10+ receptacles. I usually only like to put 2 or 3 of the counter top receptacles on a circuit. In this case I'd have 3 or more circuits serving the countertop. For calculation purposes would I have to use more than the two required 1500A small appliance branch circuits?

I guess the same question would apply to the scenario of 2 countertop receptacle circuits and then a seperate one serving the dining room.

 

[bphgravity]

See 210.52(B)(1) and Excpetion 2 for your first question. It can be either - or.

Your second question is answered by 220.52 and its exception which permits the refrigerator to be included in the small appliance calculation. The microwave, if permanently installed, must be included in the calc.

A heat pump and the aux. heat can and will operate at the same time.

 

[dahualin]

Refrigerator: it can have its own dedicated circuit or put in the small appliance circuit. I normally give it a dedicated circuit.
Microwave: If it is fixed above stove, it needs a dedicated circuit. Otherwise it can be powered by small appliance circuit.
I usually include both refrigerator and microwave in load calc (Microwave is fixed above stove).
HVAC: AHU and condensing unit will work together in Summer; AHU and auxiliary heater will work together in winter. If you are using heat pump system, then the outdoor heat pump unit will also work in winter. You shall compare the load for cooling in summer and heating in winter and take the larger one for load calculation.

Small appliance circuits: Code requires minimum 2 small appliance circuits for each residential kitchen area. If you have 3 small appliance circuits, it is allowed by code. I have done once with 3 small appliance circuits for a very big kitchen.