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Discussion Starter #1
Does it matter if the meter was designed for 240volts?

I thought it just reads watts?

Thanks

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Discussion Starter #3
Hello Mike,

Normally most meters are design for 120/240 vac and rated for either 100 or
200 amp.

There should be two incoming cable lugs on top, and load lugs on the bottom.
There should also be a insulated neutral bar down the center with a ground
strap connected to a ground bar that is bonded to the meter housing.

In some meters, the rotating drive unit is power by 120 vac. To meter 120
vac only, come in the top feed lugs with the same 120 vac line. Run the
incoming wire to one lug and jumper over to the other lug. Connect the
neutral to the center solid neutral bar.

Disconnect the grounding bond strap that goes from the center solid neutral
bar that goes to the ground bar if there is one install. Because this is
not the first disconnect device from the service transformer, you then run a
separated ground wire from your breaker panel to the meter.

Only at the first disconnect, the neutral is bonded to ground and then to a
ground rod. This is not necessary if you are using this meter as a sub
assembly, but you must run a separated ground wire.

Your 120 vac feeder should be a 3-wire, a Line 1, a neutral and ground wire
rated at the same ampere as the branch breaker you connect to.

On the load side lug, you can connected to the same side that the Line 1
came on top feed lugs and also the neutral and ground connections.

Put a load on the meter and see if the meter turns. If not than switch the
120 v wire on the load side to the other lug. Normally the meter motor is
taken off only one of these meter lugs. It may be best to install a wire
jumper from one load lug to the other, so it does not make any difference
which load lug you take off.

Roland


----- Original Message -----
From: "mike golub" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Thursday, August 23, 2007 10:10 AM
Subject: [EVDL] hooking up old house watt meter


> Does it matter if the meter was designed for 240volts?
>
> I thought it just reads watts?
>
> Thanks
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev
 

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Discussion Starter #4
Unless you mean using a power meter meant for house power to measure
DC battery power? That may or may not work; depending on how they
measure AC power, it may give inaccurate results for DC.


The typical household watt-hour meter will only work for AC at the
design frequency and power factor. It will be out of calibration
at another frequency, or power factor, and not work at all on DC.
You can check the calibration by using a known load (ie a resistor)
such as a household heater).

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