Residential service size rule of thumb

Does any know a good rule of thumb about an electrical service size based on square footage of home and no gas appliances? I have a home with 125 amp service and the home is about 1500 sq feet under air.

How many panels? How many open spaces for additional breaker installations? Is this a pool home? 125 amps is low but not a big deal if the circuitry is OK. How old is this home? Are you in Florida? Please answer.

Post this in the electrical section.

From my limited Canadian knowledge, 125 amps should be adequate if all the other electrical appliances are average sized.

In Florida, no pool, two sub panels, 1 is for the main home and the other is for a small utility closet where the HVAC and water heater are.

sorry the attacment was to large

You just can’t add up all appliances by their amperages…some loads are calculated at %'s of the rated…some loads can be exclusive of each other such as heating/AC.

Go to the electrical thread!

3watts per square foot for liighting and general outlets,add this to the amount of watts for all your other items, water heater, hvac including electric heat if you have it, 2 kitchen appliance outlets=1,500 watts and the wattage of any thing else you will be running off the panel ie. shop, pool equipment ect. Now all of those things are not operating at the same time, so the NEC lets you take 100% of the first 10,000 volts-amperes and 40% of the balance. Say your total watts or volt-amperes is 40,000 so you have 10,000+0.4x30,000= 22,000 volt amperes. Now 22,000va/240v=91.7 amps round up to 92amps + 25%=115amps. This would fill up a 125 amp service panel I would recommend a 150 amp panel for future add ons. Keep in mind your limited to 42 breakers/circuits in a panel.

I hope this helps. To convert watts to amps divide watts by volts. water example 4500 watts/240v=18.75amps.that is for breaker size not service panels. attachment with my first reply was too large to upload. check my other post.