Home generator question

Status
Not open for further replies.

Matt N

Member
Location
Alameda, CA USA
My clients house main is a 320 continuous with one of the 200’s supplying the main house. Most folks are saying a 20KW is fine for 200-amps, but when I read the specs—the 20KW pumps out only 125 amps.
should I get a 30KW to be safe?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
200a is 48Kw at 240v. A generator must be sized for the peak load, including starting currents. What do you see as a realistic maximum peak usage?

You really need to perform a desired-load calculation that includes any equipment that will auto-start (like HVAC) unless load-shedding is employed.
 

Matt N

Member
Location
Alameda, CA USA
200a is 48Kw at 240v. A generator must be sized for the peak load, including starting currents. What do you see as a realistic maximum peak usage?

You really need to perform a desired-load calculation that includes any equipment that will auto-start (like HVAC) unless load-shedding is employed.
I will do some load calculations but here’s what I know: 50-amp car charger, 30-amp dryer and 50-amp oven. All other appliances are gas (4000sqft house).
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I will do some load calculations but here’s what I know: 50-amp car charger, 30-amp dryer and 50-amp oven. All other appliances are gas (4000sqft house).
You also have to include a discussion with the customer. Most don't expect to do laundry or cook in the oven during outages.
 

Hv&Lv

Senior Member
Location
-
Occupation
Engineer/Technician
Now days POCOs can tell you what the demand is on the house. Call and ask. Or look at the meter and see if ”PD” is showing on the scroll.
 

Barbqranch

Senior Member
Location
Arcata, CA
Occupation
Plant maintenance electrician Semi-retired
You also have to include a discussion with the customer. Most don't expect to do laundry or cook in the oven during outages.
They may not even be aware that the power went out and they are running on generator.
 

shortcircuit2

Senior Member
Location
South of Bawstin
Size generator for largest expected load and use load control management on larger loads. I say the 20KW can be designed to serve your application. 30KW will be a waste of money and fuel.

Soon there will be Power Control Systems (PCS) available to incorporate the EV battery as backup to the dwelling. See 705.13 2020 NEC
 
Status
Not open for further replies.
Top