Should there be amps on my main ground???


Old 08-31-05, 02:17 PM
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Should there be amps on my main ground???

I am new to this forum so I just wanted to begin by saying greetings to all.
-- I have been having a problem with my electrical bill. It is always about double that of my friends and neighbors. The local electric company has been less than helpful in this situation. I have been rewiring and replacing appliances with high efficiency ones but none have changed the usage per month of electricity.
I recently started checking wires with my amp clamp and most everything seems normal accept the main ground. I discovered about 9 amps on the main ground from the cb box to the meter. I narrowed it down to 2 breakers at about .75 amps each and the furnace fan at 7.5 amps. The largest draw only shows when the furnace fan is running not the AC unit. I checked the fan out and found none of the 3 wires shorted to ground or leaky.
Is this normal???
Any help would be great.
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Old 08-31-05, 02:43 PM
Join Date: Sep 2000
Location: United States
Posts: 18,497
That much current on your ground wire is not particularly good, but it's not a smoking gun of your problem either.

Many power companies offer an energy audit service at a nominal price. If yours offers such a service, I suggest you take advantage of it.

Compare your home with your friends and neighbors. More or less people living there? Better or worse insulated (has anybody upgraded the insulation)? More or less air conditioning? At what temperature is the thermostat set? Are the major appliances gas or electric? Do you have the same kind of windows? More or less square feet? Does anybody in your family take long showers? Do you have a pool or hot tub? Do your kids leave the doors open? Do you have a chest freezer in the garage or basement? Do you wash your clothes in hot water? Are you on the same rate structure?

Any of these differences might be significant.

Are you running the furnace at this time of year?
Old 08-31-05, 02:55 PM
Join Date: Sep 2003
Location: Central New York State
Posts: 13,973
I suspect that you may be confused and are actually measuring the neutral, or return, current, and NOT ground current.

The utility supplies you with power on two wires. These two wires measure 240 volts (ac) between them. To enable you to have 120 volts, they also supply you with a neutral wire. Back at the transformer where they make these connections is important, but to you all that matters is that there is 120 volts between each hot wire and this neutral wire, and 240 volts between the two hot wires. However, the utility only provides you with these three wires. None of these three wires is ground.

If all of your electricity being used were 240 volts, there would be no current on your neutral wire, as the return current for 240 volt devices in on the two hot wires themselves. An example would be an electric water heater. If this was all that was running in your house, you would not need a neutral.

Likewise, if you managed to pull the exact same amount of power through each hot wire for 120 volt devices, you would also not need a neutral back to the utility, as there would be no return current. An example here would be two 100 watt light bulbs, each one powered from a different incoming hot wire into your house.

However, in reality you don't have a perfect match and there is some current that must return to the utility via the neutral wire. So measuring current on the neutral wire that goes back to the utility means nothing, especially the way in which you have described it.

Now enter the ground connection.

To provide a reference point for the voltage and to allow for some margin of safety, the neutral wire is connected to ground somewhere at your residence. It should only be connected to ground at one place. This is usually either at your main circuit breaker panel or at the meter itself. The ground connection will be through some metal into the ground. Depending on the installation, it may be through more than one location. Common connections include the metal incoming cold water pipe and one or more ground rods inserted into the ground.

Now if you measure current on the ground wire that runs to the metal water pipes, or on the wire that runs to the ground rod then there is something to investigate.
Old 08-31-05, 03:59 PM
WFO is offline
Join Date: Feb 2004
Location: usa
Posts: 247
The neutral current should be the difference between the currents of the two hot legs.

"I have been having a problem with my electrical bill. It is always about double that of my friends and neighbors."

Like John Nelson said, no two homes are identical and no two lifestyles are identical. Comparing house bills is comparing apples to oranges.

On the other hand, if they do all the expensive things (washing a lot, low AC settings, lousy insulation) and you don't, start looking!

Most high bills at our Co-op utility arise when something that you rely on to function correctly, doesn't. For example, a faulty thermostat that doesn't cut off, a well that is water-logged and cuts on and off repeatedly, a leak in the water line that makes the well run, a leak in the hot water line that makes the H2O heater run too much, low freon levels in the runs continuously because it can never cool enough (same goes for the 'fridge), a tear or break in the cooling ducts spilling air into the attic, etc.

I've seen underground (URD) circuits with high impedence faults to ground that don't draw enough current to trip the breaker, but spin the heck out of the meter!

We've even had several occasions where the AC and heat strips operate simultaneoulsly!

After 20 years in the Co-op meter dept., the fastest meter I ever tested was 30% fast (and it had taken a direct shot of lightning....everything in the house was fried). The second fastest was 9%. In fact, I can count them all on one hand (out of literally thousands tested) that were fast enough to require a billing adjustment. When a meter is off, they are usually off to the customers favor (slow) and nothing makes a high bill customer madder than when we have to speed up his meter because it was too slow

Just letting you know that it usually isn't the meter, and the test can go for or against you. If you decide you do want it tested, you have that least in Texas.
Old 08-31-05, 09:08 PM
Join Date: Nov 2004
Location: CA
Posts: 2,041
Be careful inside the panel! What you are interested in is how much current is flowing in each circuit. You didn't tell us what your kilowatt usage was, but your bill probalby itemizes 'X' many KWH per day. Start to add up what you have running. eg. a 120 watt bulb running 1 hour = 0.1 KWH

The "stealth" loads that can add up are things like power cubes plugged in 24/7. Each on of these uses a numer of watts even it the device they feed is turned off. Light dimmers set on very low, instead of OFF. Etc.
Old 09-01-05, 10:07 AM
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
I once investigated an increase in a utility bill, and the problem was a large combination freezer/fridge appliance.

Any freezer/fridge/A.C. must first absorb heat,and then dissipate the heat absorbed.This unit was located on an inside wall and wedged between two base cabinets so that the absorbed heat was "trapped",bad enough, but the "culprit" was the defective fan motor which circulated air across the compressor motor.

The hotter the air surrounding the compressor motor and condensing-coil, the more the compressor motor has to consume electrical energy in order to dissipate the heat energy.

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