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# Measuring total house current

## Measuring total house current

#1
07-17-14, 02:26 PM
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Join Date: Jul 2014
Location: USA
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Measuring total house current

To determine what size generator I need, I want to know how to determine the total current draw when I have both 110 and 220 devices running. I have an AC/DC Fluke clamp adapter but I'm not sure if I measure each hot leg of the 220 entrance and add them to get the total draw?

#2
07-17-14, 02:55 PM
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Welcome to the forums.

You could measure both legs of the service to compute current draw but usually you add up the wattages of the connected loads. During a power failure you need to conserve power and not everything needs to run.

#3
07-17-14, 03:10 PM
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I agree...you'd have to turn on every appliance, A/C, fan, lamps, etc, to get an accurate representation. That can be hard to do when some loads are intermittent (fridge, A/C, etc).

Better to just read the nameplate data on essential items such as fridge, freezer, A/C or heat, lights, computers, TV, and such. Adjustments can always be made when Mama/Daughter absolutely needs her blow dryer when the power is out.

Most people could easily live almost normal life with an 8KW steady load standby genset. If you want every modern amenity with no lifestyle impact, then it could shoot up to 20KW pretty easily.

If you really want a whole house standby gennie...then it will probably need Pro install and they will do any load calcs needed.

#4
07-17-14, 03:51 PM
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Join Date: Mar 2006
Location: Wet side of Washington state.
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Unless you have money to burn sizing a generator to supply the entire load of your house is extreme overkill. A kitchen range all by itself could use between 8 and 12 kilowatts, a water heater is generally 4.8 kilowatts. Air conditioning could be a minimum of 6 kilowatts and the A/C would also have a starting load that could be three times the running load.

A 200 ampere (at 240 volts) service is 48 kilowatts. A 100 ampere service is 24 kilowatts.

I have a 200 ampere service but I have a 2.8 kilowatt generator (3 kilowatts surge for 20 minutes) and I have no problem living with this when the power goes out. It handles my furnace, refrigerator, microwave oven (or table top convection oven or hot plate) along with my TV and video equipment pr Internet connection and a few lights. The smaller the generator the less it costs to purchase and the less it costs to operate.

#5
07-17-14, 06:24 PM
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WHAT ?!!?!?!? No blow dryer Furd

I consider myself lucky in that all my appliances are natural gas. I use a 5K Honda and run the entire house. Washer and dryer same time. Microwave no problem. No central air.... just ceiling fans. I used about 5-6 gallons of gasoline a day.

#6
07-17-14, 06:27 PM
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There are demand load calculations for generators available online.

#7
07-17-14, 10:44 PM
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Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 16,321
WHAT ?!!?!?!? No blow dryer Furd
Nope, no women have lived here for quite some time. I think it has been eight years or more since one even spent the night.

#8
07-18-14, 05:15 AM
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Nope, no women have lived here for quite some time. I think it has been eight years or more since one even spent the night.

To the OP, google generator load calculator and you should be able to find a handy tool to calculate your load. However, if this is a whole house standbye generator, don't sweat it, the electrician you hire for the install will do the appropriate load calculation to assure you have an efficient sysystem installed... all you have to worry about is signing the check.