Hi, What is the optional method for a load calc? Can this be used on a sub panel?
I used an online calculator and got the following:
General Light and Receptacle Load 1308sqft x 3VA = 3924VA ________________________________________ Small Appliance Circuits Load 2 x 1500VA = 3000VA ________________________________________ Laundry Branch Circuit(s) Load 1 x 1500VA = 1500VA ________________________________________ Total General Load Less Demand sum of above less T220.11 demand sum of above = 8424VA first 3000 at 100 % = 3000 next 117,000 at 35% = 1898 remainder at 25% = 0 sum less demand = 4898VA ________________________________________ Fastened In Place Appliances Load Disposal = 1176VA Garage Door = 1000VA Dish Washer = 1600VA Attic Fan = 700VA Microwave = 975VA sum less 75% demand = 4088VA ________________________________________ Clothes Dryer Circuit(s)Load Total dryer circuit(s) load = 0VA ________________________________________ Cooking Appliance(s) Load Range 9.5kVA T220.19 Column A = 8kVA T220.19 Column B = 0kVA T220.19 Column C = 0kVA Total calc.d range load = 8kVA ________________________________________ Heating or Air-Conditioning Load Air Conditioner = 4240VA ________________________________________ Largest Motor Load 25% of largest motor = 1000VA ________________________________________ Total Computed Load 22226 Volt-Amps ________________________________________ Computed Amperage 22226 divided by 240 = 93Amps
Is there anyway to get this down so I could connect a dryer to it?
See NEC 220.30. This usually comes in smaller than the standard calculation. You also must have a service or feeder rated at 100A or more in order to use it (so I think you're OK with a 100A subpanel if its on a 100A feeder).
When I run your numbers with the optional calculation, I get 90 amps including a dryer. This was based on: 3.92 KVA living space 4.5 KVA small appliance circuits 5 KVA Dryer 9.5 KVA range 1.6 KVA Dish Washer .98 KVA Microwave 1.18 KVA DIsposal 1 KVA Garage Door Motor 0.7 KVA Attic Fan
This comes to 28.38 KVA. The first 10 KVA are 100% and the remaining is 40%. So this reduces the load to 17.35 KVA. Then we add the Air Conditioner at 4.24 KVA giving a total of 21.6 KVA which is 90A.
About the only thing I can comment on your standard calculation you included is what air conditioner amp rating did you use? Was it MCA or FLA+RLA? If its MCA, that already has the 25% factor for the largest motor so you can remove that item from the calculation.