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Old 04-12-2009, 12:32 AM
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Home KW Hour Meter "Close Up"

Hi All,

In a earlier thread and maybe unrelated was a discussion on "Home Kilowatt Hour Meters" the four jaw type, rated at 200 amps at 240 volt and this is some of my explanations on the importance of load balancing.

The way the watt hour meter operates is the amperage or load is divided into two power legs or phases 120 volt line to ground circuits, each of the two being metered on a home 3-wire system (utility transformer or power lines to utility watt hour meter base). If one leg or phase of the 120 volt line to ground is at 40 amps and the other 120 volt line to ground is at 80 amps your pay for the 80 amps the higher of the two. If both 120 volt line to ground legs or phases are balanced at 60 amps per leg or phase ..... right you pay for the 60 amps ..... not the 80 amp high leg or phase on a unbalance 3-wire system.

The residential 240 volt 4-jaw meter uses CT's ( current transformers ) there is no center tap transformer in the old style 5 dial kilowatt hour meter, if you turn the meter up side down ...... the meter runs backwards, thus sealing tabs for no tampering with the utility meter configuration.

Always any modifications to your electrical service system should be done by qualified person or electrician.

Now I'm fairly sure of my explanations but ..... for further clarification ...... I have several KWH meters that are the type we are talking about that was purchased 15 years ago for "House Meters" where sub metering of a electrical service is required, commonly done today.

After breaking the side seal and removing the four cotter pins and drilling out the rivets heres the inside of a standard home KW hour meter ......

If anyone can figure out by the photos exactly how this puppy really works, it would possibly be helpful to someone here in the Energetic community, any other images needed just holler

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