Power meter

bannerd · October 14, 2021, 07:27:00 AM

He all, trying to gauge what size generator I need and wondering if there is a meter I can run before our power company meter? I want to get some metrics for a generator and also some supplemental options(solar). Our power company runs an average so it's far from exact(More profit).

I found some hub kits on amazon... but the look pretty cheap (sense energy). Open to ideas, Thanks!

firefighter ontheside · October 14, 2021, 07:42:10 AM

What do you have that's electric? Furnace, oven, dryer, water heater? If you don't have those, your generator needs will be much smaller. I have a 17.5 kw generator and it will run everything but my electric furnace. With all gas appliances, you probably don't need more than about 7 kw.

YellowHammer · October 14, 2021, 08:00:13 AM

What do you estimate you need as far as current and voltage?

The best way is to get a clamp on ammeter, rated for your input voltage. Probably, you'd need one sized for HVAC use, because they can measure high currents. Clamp it on one of your line service lines going into your breaker. panel, downstream of the power meter, and start up your equipment one by one and read the current going through the service line.

Power (Watts) = Current (amps) x Voltage.

Then take the actual measured maximum power requirement, multiply by 1.2 (generators have an 80% service factor) and that is the minimum power your generator needs to provide.

These meters are invaluable, they will help you diagnose all kinds of electrical motor related problems. Get a good one, you'll use it the rest of your life.

You can then directly measure your requirements for each machine, all you machines combined, average needs, and most importantly the start up "inrush" or startup current, which spikes much higher than steady state and must be covered by your generator.

You can also estimate your requirements form reading the faceplates from each machine you use, it will have the current requirements. However, the best way is to just measure it.