mivey
Senior Member
Because 3 volts is your NEV and you are not bonding well to it everywhere.
What is the current in your bond wire at the one end?
Neutral voltage
- Thread starter cknight
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What is the current in your bond wire at the one end?
kwired
Electron manager
- Location
- NE Nebraska
From within OP:
He disconnected bond wire (main bonding jumper?) and isolated service neutral from local bonding/grounding - the service neutral still had 3 volts on it - the stray voltage is coming from something ahead of the service, could be in the meter, at the drip loop (if overhead service) at the first pole, three miles away on MGN. Something is causing a rise in voltage on that conductor. If main is off it isn't voltage drop on the service neutral, though that is one place where such a rise can occur when on and loaded.
:thumbsup:
Then the premises side would have had the voltage on it instead of the service side when the bonding was opened, and likely would have risen even more after opening.
It's a back to back service. I removed the ground wire going to the ground rod and re checked the earth at the ground rod for NEV and it was down from 3 v to .3 v. Then removed the pool bond wire and got the same. All area surrounding the pool, the service,the water and the concrete was at .3 v. The neutral still had 3 v on it at the main panel. This is testing by using a probe with a wire on it hooked to one side of the meter stuck in the front yard and then using the other meter lead to these misc. areas.
kwired
Electron manager
- Location
- NE Nebraska
Nothing wrong on the premises, 3 volts is coming from utility, and there is some chance there is nothing you can do about it, and a reason equipotential bonding is required at pools. If you are having voltage issues at the pool there must be holes in the equipotential bonding system, or there is little or no bonding been done to begin with.
kwired
Electron manager
- Location
- NE Nebraska
I think you are looking at things the wrong way. I went and reread your OP again - sounds like most everything except water is rising the same 3 volts you are getting on the service neutral. That tells me those items apparently are bonded pretty well - but for some reason water isn't and is much closer to "ground " potential.
When I said you are looking at things the wrong way - with this equipotential bonding you really don't care about "ground", you want everything a pool user can simultaneously contact to be at same potential regardless of what voltage it may be to "ground". That leaves pool users in similar situation as a bird sitting on a high voltage line, doesn't matter what voltage that line operates at - they don't get shocked because they can't touch anything that is at a different potential.
mivey
Senior Member
The parts that do not reach the neutral voltage have a bad bond.
West side concrete is at 3 volts. It has a good bond.
East side concrete is at 0.5 volts. It has a bad bond.
mivey
Senior Member
Could just be a lot of single-phase load on a radial feeder. May not be stray voltage at all. What is normal for that feeder is unknown but a NEV of 3 volts would not necessarily be abnormal.
If unusual for that feeder, POCO could check to see if a capacitor fuse is blown or line regulator not working correctly.
kwired
Electron manager
- Location
- NE Nebraska
I agree, but isn't stray voltage only "stray" until you know what is causing it?
Most of what people call "stray voltage" on a neutral is just results of voltage drop somewhere on that MGN, cause might be from primary current, might be from secondary current - either way there is a rise in voltage to "ground" when there is voltage drop across an otherwise grounded conductor, and if current is flowing there is some voltage drop across that conductor.
even if the bond is bad wouldn't the NEV be the same on both sides of the pool? Or at least close. The east side and the water read the same. Disconnect the bond and everything reads the same. Usually the NEV is the same all the way around the pool right? At least in the earth. Probably overthinking this. What is safer? No bond connected back to pool pump and all at the same reading or bonding it and having 3 volts present.
NEV will remain same if ground resistance is zero. In your case it is not so. So you see different NEV's at different measurement points.You cannot dispense with bonding. It is a code violation. Apparently, with bonding you are getting shocked. The solution may be as I suggested earlier: Provide (additional) loop with a metal strip around the pool bonding all the nearby metal objects.
kwired
Electron manager
- Location
- NE Nebraska
The east side and the water appear to both be at "ground" potential. Some point. They either are not bonded or some point in bonding between those and the other items has failed. You want everything at same potential - hence the reason for all the bonding. but you must also bring EGC to pool pump or other electrical equipment in the vicinity - that introduces any rise in voltage from the service grounded conductor (which is normal to have low levels of rise on it because of voltage drop when it is carrying current) If everything is bonded well, you won't measure that voltage in the pool vicinity, you will measure it to ground references placed away from the pool area though. If you do measure it in the pool area one item is at ground potential and the other is at the equipotential bonding system potential.
Again you are not "grounding" objects in the pool area, you are "bonding" them together so there isn't any potential between them.
mivey
Senior Member
Stray voltage is a potential that should not exist during normal equipment or system operations. The 3 volt NEV may be completely normal but we do not know. I would call 10 volts abnormal under most conditions. 3 volts is not so rare.
Normal NEV is, by definition, not stray voltage.
mivey
Senior Member
The NEV will be the same on both sides if you have a good bond between both sides.
It is safer with a bond and 3 volts all around.
Don't think I worded that correctly. I meant the NEV in the earth. Not the concrete. The concrete is only 6' around the pool, then just dirt. I would think the NEV would be the same in the dirt if that's what it was. Disconnect the bond and it's not there in the earth.
kwired
Electron manager
- Location
- NE Nebraska
I am assuming "NEV" means neutral to earth voltage.
Earth is earth, the pool and everything that is supposed to be bonded to it very well may be different potential then earth - I keep trying to stress this point - it is the reason equipotential bonding is necessary for safety of users of the pool. We don't care what NEV is we care what potential is between objects in and around the pool. The fact that the EGC of pool pump and any other electrical items involved is also connected to the service neutral means the pool and entire EPB system will be at same potential as service neutral (if EPB is done correctly and has no holes in it)
The fact OP has voltage between items that should be bonded together means there is a failure of bonding somewhere. Anything that is at same potential as "remote earth" is what isn't bonded to the EPB system.
Earth is earth, the pool and everything that is supposed to be bonded to it very well may be different potential then earth - I keep trying to stress this point - it is the reason equipotential bonding is necessary for safety of users of the pool. We don't care what NEV is we care what potential is between objects in and around the pool. The fact that the EGC of pool pump and any other electrical items involved is also connected to the service neutral means the pool and entire EPB system will be at same potential as service neutral (if EPB is done correctly and has no holes in it)
The fact OP has voltage between items that should be bonded together means there is a failure of bonding somewhere. Anything that is at same potential as "remote earth" is what isn't bonded to the EPB system.
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