looking for ideas. went to a call, owner saying that they are getting a shock when they touch a hose bibb. stuck a probe in the ground and attached a meter lead to it and the other to the bibb 14 volts present. went though the usual test turning off breakers and watching meter. turn off all single pole breakers and no change start turning off two pole breakers, turn off pool pump and voltage drops to 9 volts, turn off water heater and drops to 5 volts, turn off a/c and drops to 2 volts, with all breakers off still has 2 volts. water lines are all copper, bonded to to the ground rod conductor. panel is bonded, all connections tight. this is a home built in the 70's three wire entrance from meter to panel. about 25'. called Power co. they came out changed some ground rods a transformer, underground service from trans to meter about 30'. does no mater which two pole breaker is no or combination of two pole breakers the voltage goes up and down about 4 volts each accordingly. also measured at the ground rod with probe in the ground about 2 feet from ground rod one meter lead on probe the other on ground rod conductor 5-6 volts. measured from hose bibb to ground rod conductor 0 volts. any help will be welcome. Thanks
voltage at hose bibb
- Thread starter MichaelJ
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starbolin
Senior Member
- Location
- Rancho Buenaventura, California
Install has at least two, maybe more, problems. First is something is putting current on the GES. Current on the GES means a fault from hot to ground. Your voltages suggest the current is somehow related to load. Odd that these are supposedly balanced loads. An amp clamp on the GEC may be more illuminating here.
Problem 2 is the water bond and GES are not doing their job of reducing voltage on the water system. What is the ground impedance? Question is, is the water system energizing the GES or is the GES energizing the water system? You'll need to open the water system bond to find out. After safeing the occupants of the house of course.
Problem 2 is the water bond and GES are not doing their job of reducing voltage on the water system. What is the ground impedance? Question is, is the water system energizing the GES or is the GES energizing the water system? You'll need to open the water system bond to find out. After safeing the occupants of the house of course.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
The bond from the grounded service conductr to the water pipe, grounding elecrode, equipment grounding system, etc. does not reduce voltage on those items, it brings them all to same potential as the grounded service conductor. Should there be a reason for elevated voltage on the grounded service conductor (and I bet there is), it will raise everything bonded to it to same level. I'd be looking for bad connection in the grounded service conductor or even long undersized conductor causing voltage drop when loaded - the more balanced the neutral load is the less current it carries - the less voltage drop is present. You must also remember if you turn the service disconnect off and still have voltage present - that voltage is possibly coming from POCO, whether it be from other customers on a same feed and the voltage drop their load creates, or from voltage drop on the neutral of the primary side of the transformer - it is also bonded to the secondary neutral and and rise in voltage above ground on that will be imposed on everything bonded to it.
- Location
- Placerville, CA, USA
- Occupation
- Retired PV System Designer
If the voltage to remote ground us 14 volts, and if the POCO transformer neutral is close to remote ground, then if the resistance of the POCO neutral to house is only one ohm, then the current would have to be 14A, which is very large.
If the neutral is compromised, the current could be lower.
As for the existence of neutral voltage and current with a balanced load, I suppose it is possible that a similar impairment of one of the hot wires could shift the neutral voltage of the system as well.
If I lifted the water pipe bond, I would have all of the main open and apply loads directly (but carefully) to the service wires.
Or close only one breaker with only receptacle loads and plug in only my test load. Otherwise I would be risking anything energized in the house if there really was a neutral impairment.
Finally, if the POCO transformer secondary midpoint is really moving 14 volts away from remote ground, it would be an indication that even if the direct ground electrode is in good shape, the resistance to ground of the entire MGN is a lot higher than it should be.
If the neutral is compromised, the current could be lower.
As for the existence of neutral voltage and current with a balanced load, I suppose it is possible that a similar impairment of one of the hot wires could shift the neutral voltage of the system as well.
If I lifted the water pipe bond, I would have all of the main open and apply loads directly (but carefully) to the service wires.
Or close only one breaker with only receptacle loads and plug in only my test load. Otherwise I would be risking anything energized in the house if there really was a neutral impairment.
Finally, if the POCO transformer secondary midpoint is really moving 14 volts away from remote ground, it would be an indication that even if the direct ground electrode is in good shape, the resistance to ground of the entire MGN is a lot higher than it should be.
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