Current in earth-ground wire

[MikeF2316]

An easy one this time. What is a typical current in the wire to the earth ground in a suburban setting? My wire is about 25 feet long and connected from electrical panel to the cold water pipe between the outside basement wall and water meter.

2 nights ago, I checked mine with a cheap clamp on meter that has a 0-200 amp scale, so not super accurate. I was getting .5 amps sometimes, and at others around 1.1. Tonight I checked again, I'm now getting readings of 0.0 and 0.1. At both times I was barely using any power, 9 amps in one leg, 5.5 in the other and 3.5 in the neutral.

It's pretty hard finding anything on google, I did find one where they seemed to indicate anything up to 6 amps was within spec.

 

[theoldwizard1]

An easy one this time. What is a typical current in the wire to the earth ground in a suburban setting?

In theory, it should always be zero.

My wire is about 25 feet long and connected from electrical panel to the cold water pipe between the outside basement wall and water meter.

Likely that was acceptable based on what version of NEC was used when the house was built.

2 nights ago, I checked mine with a cheap clamp on meter that has a 0-200 amp scale, so not super accurate. I was getting .5 amps sometimes, and at others around 1.1. Tonight I checked again, I'm now getting readings of 0.0 and 0.1. At both times I was barely using any power, 9 amps in one leg, 5.5 in the other and 3.5 in the neutral.

If you really want to follow up on this, get a more accurate clamp meter.

 

[Rookie2]

There is a bad connection somewhere ,probably a neutral. IMO

 

[rockwithjason]

there is always a little flow because it's not a perfect world. I wouldn't worry about 1/2 an amp.

 

[sberry]

In a suburban setting with city water its hard to find something like that. Like Jason said, not a real deal but you could flip off circuits to see is one was leaking, possibly outdoor underground one.
Now,,, for the Wizzard,,, its wired correctly then and now.

 

[myredracer]

Normally should be zero. I would try and find the cause by shutting off circuits one by one. It is possible to be something that could get worse over time. Could be a bad hot water tank element or defective appliance. If whatever is causing it were to be on a GFCI receptacle or breaker, that amount of current is way more than a GFCI needs to trip.

The current reading may not always be the same if the cause happened to be a faulty HWT element since the element turns on and off as the thermostat calls for heat, or in an appliance that is turned on and off.

But yes, perhaps a cheap meter is not the best tool for diagnosing this. You could take say a toaster or hair dryer with a known wattage, calculate the current at 120 volts and see what the meter reads. Some meters also do not read very accurately near a zero reading - put on lower scale if it has one. In any event, you still could have something faulty in the house and should not dismiss that possibility. Might even try checking tightness of all terminations in your panel as a matter of course too.

 

[sberry]

An appliance is an interesting thought, maybe someone could come up with a connection between it and an element but this is current flowing in or out of the house. Shut the main off,,, may not even be from your house since its on city water and interconnected electric.

 

[dave*99]

First, you did measure the correct components. The neutral wire should carry the difference in current between the phase legs. If your meter is accurate and your readings are really 5.5 and 3.5 in the phase legs, then the neutral should carry 0.5 Amps.

Keep in mind that assumes the neutral has good continuity all the way back to the distribution transformer.

When the neutral becomes resistive, as in a bad connection etc., the current will then travel on the ground conductor. I would repeat the measurements with a better meter.

It may help to measure the voltage between the neutral and the ground conductor too.

There are other ways current can get on the ground conductor, but first things first.

 

[checkthisout]

An easy one this time. What is a typical current in the wire to the earth ground in a suburban setting? My wire is about 25 feet long and connected from electrical panel to the cold water pipe between the outside basement wall and water meter.

2 nights ago, I checked mine with a cheap clamp on meter that has a 0-200 amp scale, so not super accurate. I was getting .5 amps sometimes, and at others around 1.1. Tonight I checked again, I'm now getting readings of 0.0 and 0.1. At both times I was barely using any power, 9 amps in one leg, 5.5 in the other and 3.5 in the neutral.

It's pretty hard finding anything on google, I did find one where they seemed to indicate anything up to 6 amps was within spec.

Induction.

 

[Mustang51js]

You will also pick up small amps from cable grounds, disconnect cable ground and see if it goes away

 

[MikeF2316]

Thanks for all the replies, I think rockwithjason and sberry are correct. When I got home from work today, the ground wire was reading around .8 amps. My wife wasn't home, so nobody to squawk if there's no power for a few minutes. I flipped the main breaker, there was no change. My service is connected to the overhead wires at exactly the same point (well within a foot) of my next door neighbour and 2 houses across the street. Obviously our neutrals are going to be at exactly the same potential. The earth grounds are obviously much further apart, both physically and electrically. I know the guy next door has a plastic water service (just redone about 5 years ago), so he must be using ground rods. And the houses across the street are about 120 feet away.

And yes, it's a crappy meter, with only 2 scales, 0-200 and 0-1000 amps. And the reading isn't steady.

 

[wyliesdiesels]

With an insulated screw driver, remove the GEC from the water line. Then recheck for current.

 

[zmaxmotorsports]

I remember changing out a water heater years ago and getting sparks and the lights went off when I unhooked the union on the gas line,I about pissed my pants on that one!
Lost the neutral on service coming into the house and it somehow was using the steel gas service to complete the circuit.

 

[rockwithjason]

I remember changing out a water heater years ago and getting sparks and the lights went off when I unhooked the union on the gas line,I about pissed my pants on that one!
Lost the neutral on service coming into the house and it somehow was using the steel gas service to complete the circuit.

yeeee hawwwww! git r done!

 

[sberry]

I had a call about a spark at a garage panel. The dipstick were trying to insulate it, wonder they didn't get in series with it. Turns out gramps figures himself a spark and runs power to the garage thru an old water line. Hooks the n at the main to the pipe with a clamp and the other end to an old service panel as a sub.
2 side feed. Whole place is a neutral conductor, shocks everywhere. I really want no part but I did take a wire he had fished for a loop for a lite and convert it to N.

 

[sberry]

I seen some shabby **** but that was bad. I got another bud you cant splain a missing link to as he knows more than most do about this sort of thing,

 

[redmondjp]

So it sounds like the source of the stray ground current is from outside your residence - it just happens to be finding a lower-resistance path back to its source through your ground connection. Make sure that all of your metal service entrance piping (water, gas, etc) is properly bonded to ground per the NEC and you should be good.

 

[MikeF2316]

So it sounds like the source of the stray ground current is from outside your residence - it just happens to be finding a lower-resistance path back to its source through your ground connection. Make sure that all of your metal service entrance piping (water, gas, etc) is properly bonded to ground per the NEC and you should be good.

Yes, I had a feeling that was the problem all along. I will definitely monitor this.

 

[MikeF2316]

With an insulated screw driver, remove the GEC from the water line. Then recheck for current.

Ha ha, this was easier said than done. The ground wire was zip tied to the cold water pipe leading from the basement ceiling down to the floor where the meter is. Some were behind drywall, but I could reach up and feel. I got the ground wire isolated from the pipe everywhere. At this time the clamp meter was reading only 0.1 amps over near the panel.

To keep myself safe, I used my motorcycle jumper cables to connect the wire to the pipe while making meter connections. Using a much more accurate meter, I got .085 amps or .022 volts. When the wire was disconnected (or reading voltage) the clamp on meter went to 0.0

All was a waste of time, though. The ground clamp was a bit of a mess, cobwebs, dirt and corrosion. I took the time to clean it up, including the wire and pipe.

 

[wyliesdiesels]

I remember changing out a water heater years ago and getting sparks and the lights went off when I unhooked the union on the gas line,I about pissed my pants on that one!
Lost the neutral on service coming into the house and it somehow was using the steel gas service to complete the circuit.

I had a shocking (literally; pun intended) service call recently where the water line was energized. Tenants were being shocked when they touched the hose bibs and washing machine.

After i checked things out, i discovered that the water service (right below the panel) wasnt bonded to the neutral bar.

So i found the breaker that was feeding it, and turned it off.

To make a long story short, after a day of poking around(this was a large house that had a rental unit scabbed onto it, with the offending circuit feeding different things in each unit) i tracked the issue down to an energized ground terminal on the outlet for the gas range. This caused the gas line to be energized and thus the water line.

Turns out that the ground and hot wires in the NM-b feeding the outlet were both energized from the same leg. So Im guessing that someone smashed a staple into the wire somewhere. However, the landlord didnt want to rip out all the sheetrock throughout the house to find the bad spot as there was tenants living there and she didnt have the money.

So i shut off the breaker and bonded the line. Turned the breaker back on and it instantly tripped. Had the water line been bonded in the first place, the shock potential wouldve been stopped by the breaker.

They ended up using a different outlet for the time being.

So it sounds like the source of the stray ground current is from outside your residence - it just happens to be finding a lower-resistance path back to its source through your ground connection. Make sure that all of your metal service entrance piping (water, gas, etc) is properly bonded to ground per the NEC and you should be good.

Where is the transformer located?

Im trying to picture how the current is flowing from your panel into the rod if its from a neighbor's service instead of through the neutral in your drop?

Maybe u have a bad neutral connection?

 

[sberry]

I think he is hooked to city water.

 

[MikeF2316]

...
Where is the transformer located?

Im trying to picture how the current is flowing from your panel into the rod if its from a neighbor's service instead of through the neutral in your drop?

Maybe u have a bad neutral connection?

I figure that my ground on the city water pipe is at a slightly different potential than my neighbour's ground rod. So the current flows from his ground rod to his panel, then his neutral, then through to my neutral via the line on the street and on to my ground wire and water pipe. Or maybe the other way around.