current on a grounding electrode conductor
- Thread starter ryagesh
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Re: current on a grounding electrode conductor
The amount of current you are reading is not unusual. The fact you have two paths for ground current is unusual. This is why 4 wires are run to an added panel
.
Are you reading this with a digital meter?
Bond the electrodes together. There should be only one ground electrode conductor from the panel.
There is probably nothing wrong with the neutral, if current is flowing on it.
The amount of current you are reading is not unusual. The fact you have two paths for ground current is unusual. This is why 4 wires are run to an added panel
.Are you reading this with a digital meter?
Bond the electrodes together. There should be only one ground electrode conductor from the panel.
There is probably nothing wrong with the neutral, if current is flowing on it.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
The POCO neutral I'm talking about is on the primary side of the transformer feeding this house. The reason I say that is this was one of the things that I had noticed when we had this problem with voltage on piping in a apartment building that was shocking the residents when they tried to take a shower. we measured the voltage at 56 volts to a isolated ground rod that we drove in. then we took current readings to see which way the current was flowing. this showed the water lines had been replaced with plastic, and the ground rod had about 5.8 amps on it. this was about right for the primary load on a 800 amp service at 7200 volts. when the POCO took a amp reading on the primary neutral there was no current on it and it was using the grounding electrode from the service for return path. Later on we found out why the water lines had been replaced was because of the electrolysis on it causing it to disintegrate and start leaking.
[ October 11, 2003, 12:55 AM: Message edited by: hurk27 ]
The POCO neutral I'm talking about is on the primary side of the transformer feeding this house. The reason I say that is this was one of the things that I had noticed when we had this problem with voltage on piping in a apartment building that was shocking the residents when they tried to take a shower. we measured the voltage at 56 volts to a isolated ground rod that we drove in. then we took current readings to see which way the current was flowing. this showed the water lines had been replaced with plastic, and the ground rod had about 5.8 amps on it. this was about right for the primary load on a 800 amp service at 7200 volts. when the POCO took a amp reading on the primary neutral there was no current on it and it was using the grounding electrode from the service for return path. Later on we found out why the water lines had been replaced was because of the electrolysis on it causing it to disintegrate and start leaking.
[ October 11, 2003, 12:55 AM: Message edited by: hurk27 ]
Re: current on a grounding electrode conductor
I would place a 50 ohm resistor in line and measure the voltage drop across the resistor.
This reading, you are seeing, could be from RF and the conductor is acting as an antenna.
I have seen sensitive high input meters read high on the scale, by just the leads becoming a HF antenna, in a high RF field.
I would place a 50 ohm resistor in line and measure the voltage drop across the resistor.
This reading, you are seeing, could be from RF and the conductor is acting as an antenna.
I have seen sensitive high input meters read high on the scale, by just the leads becoming a HF antenna, in a high RF field.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
Bennie most amp probes don't have leads? or are you thinking voltage meters?
Bennie most amp probes don't have leads? or are you thinking voltage meters?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
Bennie your are right about RF energy as we have a AM broadcast transmitter close to one of our subdivisions and we get some unusual readings (voltage) on wires not tied to anything. Once I thought I was going crazy when I got a little tingle from a wire that i was unspooling in the driveway getting ready to pull and I got my DVM out just to see if I wasn't imagining things and there was 47 volts on it to earth. but went away when I used a solenoid type meter. then I realized the AM radio transmitter was just behind me.
Ever try to use a tic-tracer when you have HV transmission lines over head? this was another one of those lost in space things I ran into. changed two sets of battery's before I looked up. LOL
[ October 11, 2003, 01:15 AM: Message edited by: hurk27 ]
Bennie your are right about RF energy as we have a AM broadcast transmitter close to one of our subdivisions and we get some unusual readings (voltage) on wires not tied to anything. Once I thought I was going crazy when I got a little tingle from a wire that i was unspooling in the driveway getting ready to pull and I got my DVM out just to see if I wasn't imagining things and there was 47 volts on it to earth. but went away when I used a solenoid type meter. then I realized the AM radio transmitter was just behind me.
Ever try to use a tic-tracer when you have HV transmission lines over head? this was another one of those lost in space things I ran into. changed two sets of battery's before I looked up. LOL
[ October 11, 2003, 01:15 AM: Message edited by: hurk27 ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
Yep that is true I didn't think about that. maybe an FM or TV station close by?
Yep that is true I didn't think about that. maybe an FM or TV station close by?
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
There was a Bridge in New York City that had this very problem. It was a AM radio station located just below it. And the direction of the beem was right toward it. This was in one of the electrical mags not to long ago.
[ October 11, 2003, 01:21 AM: Message edited by: hurk27 ]
There was a Bridge in New York City that had this very problem. It was a AM radio station located just below it. And the direction of the beem was right toward it. This was in one of the electrical mags not to long ago.
[ October 11, 2003, 01:21 AM: Message edited by: hurk27 ]
karl riley
Senior Member
Re: current on a grounding electrode conductor
I can add one other possibility from my experience: if you are near salt water and your rod penetrates the salt water table it can conduct the amps you measured.
Guys, if he has opened the main switch and sees no amps on the rod, how could it be primary neutral? Unless he is the only load for the neighborhood.
Karl
I can add one other possibility from my experience: if you are near salt water and your rod penetrates the salt water table it can conduct the amps you measured.
Guys, if he has opened the main switch and sees no amps on the rod, how could it be primary neutral? Unless he is the only load for the neighborhood.
Karl
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
there is one other way for this to happen:
A remote sub-panel where the grounds and neutral are tied together and has lost the neutral would return from electrode to earth to electrode.
the other thing I can think of is a underground feeder or branch circuit that has been compermized could do this too.
[ October 11, 2003, 07:23 PM: Message edited by: hurk27 ]
there is one other way for this to happen:
A remote sub-panel where the grounds and neutral are tied together and has lost the neutral would return from electrode to earth to electrode.
the other thing I can think of is a underground feeder or branch circuit that has been compermized could do this too.
[ October 11, 2003, 07:23 PM: Message edited by: hurk27 ]
Re: current on a grounding electrode conductor
Does everyone think that 2 to 5 amps on the ground electrode conductor is excessive?
Once I hit a copper vein in Arizona, while working on an Early Warning Radar Site. The ground path impedance was probably less than the neutral conductor.
Does everyone think that 2 to 5 amps on the ground electrode conductor is excessive?
Once I hit a copper vein in Arizona, while working on an Early Warning Radar Site. The ground path impedance was probably less than the neutral conductor.
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: current on a grounding electrode conductor
Yes unless as you stated.
there should always be more on the water pipe than the electrode unless the water pipe has an isolator in it.
Yes unless as you stated.
there should always be more on the water pipe than the electrode unless the water pipe has an isolator in it.
pierre
Senior Member
- Location
- Westchester County, New York
Re: current on a grounding electrode conductor
Grounding Electrode Conductors were not designed to be current carrying conductors.
Yes I think that 2 to 5 amps on these conductors is too much.
Other than short duration fault current or lightning, etc... why should there be any current at all?
Pierre
Grounding Electrode Conductors were not designed to be current carrying conductors.
Yes I think that 2 to 5 amps on these conductors is too much.
Other than short duration fault current or lightning, etc... why should there be any current at all?
Pierre
websparky
Senior Member
- Location
- Cleveland, Ohio
Re: current on a grounding electrode conductor
Pierre,
Good point!
Pierre,
Good point!
whrobinson
Member
Re: current on a grounding electrode conductor
Its not unusual to see this in my area, its a common occurance when the power company loses its neutral, or grounded conductor. Its necessary to ensure proper bonding through the use of a "Kenny Clamp" grounding electrode connector. This can help where a choke effect may occur, when current is dumped on the grounding conductor.
Its not unusual to see this in my area, its a common occurance when the power company loses its neutral, or grounded conductor. Its necessary to ensure proper bonding through the use of a "Kenny Clamp" grounding electrode connector. This can help where a choke effect may occur, when current is dumped on the grounding conductor.
- Location
- Illinois
- Occupation
- retired electrician
Re: current on a grounding electrode conductor
Don
The building grounding electrode will always have current flow if the utility has grounded conductor feeding the building. The grounding electrode system places the earth in parallel with the grounded conductor. The better the grounding electrode system, the more current that will flow. As stated in other posts, a significant percentage of the grounded conductor current will flow on a common metal underground water piping system. This case is unique in that there is more current on the ground rod then on the water piping system. There must be an isolation joint on the water system, or the water main at the street is nonmetallic.
Don
Re: current on a grounding electrode conductor
The difference in current is due to the difference in impedance, which is proof the electrodes are not bonded. Should the electrodes be bonded the current will be equal.
This is why bonding is required for multiple electrodes. This situation establishes two different earth potentials. Current will circulate though the loop.
The difference in current is due to the difference in impedance, which is proof the electrodes are not bonded. Should the electrodes be bonded the current will be equal.
This is why bonding is required for multiple electrodes. This situation establishes two different earth potentials. Current will circulate though the loop.
karl riley
Senior Member
Re: current on a grounding electrode conductor
Bennie, I didn't follow that last post, but I am still wondering why you didn't file a claim and start a copper mine?
Karl
Bennie, I didn't follow that last post, but I am still wondering why you didn't file a claim and start a copper mine?
Karl
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: current on a grounding electrode conductor
I saw the Kenny Clamp at the Orlando IAEI meeting. I'm not sure if our AHJ will require it, even though it is a good idea...nad actually the only way to meet code in terminating the GEC into a panel.
I saw the Kenny Clamp at the Orlando IAEI meeting. I'm not sure if our AHJ will require it, even though it is a good idea...nad actually the only way to meet code in terminating the GEC into a panel.
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