Pool Ladder Stray Voltage

[HughesBros.Electric]

Got a call today from an home owner saying that when they turn the microwave on, they are getting shocked on the pool ladder. They have (2) metal ladders but its just on one they get shocked on. Checked voltage to ground and the ladder had 4 volts. It only happens when the microwave is on. I havent had time to troubleshoot it all the way yet. Just want some insight on what it could be. Thanks

 

[stickboy1375]

Got a call today from an home owner saying that when they turn the microwave on, they are getting shocked on the pool ladder. They have (2) metal ladders but its just on one they get shocked on. Checked voltage to ground and the ladder had 4 volts. It only happens when the microwave is on. I havent had time to troubleshoot it all the way yet. Just want some insight on what it could be. Thanks

bond the ladder.

 

[HughesBros.Electric]

Im just curious why stray voltage is getting to the ladder when the microwave is turned on?

 

[stickboy1375]

Im just curious why stray voltage is getting to the ladder when the microwave is turned on?

i know you were, i find it hard to believe its just the microwave causing the issue....

 

[satcom]

bond the ladder.

It may already be bonded, stray is a funny duck, you can have the best bonding job and still have stray present, we have areas where entire developments can't use their pools because the stray current is high, the power company has been working on the problem for some time, short of re designing the local distribution network they tried additional grounding as some of the sub stations with limited success, some engineers feel the distribution return feeds are part of the problem, so if you bond and the problem continues, check to see if there are other pool users in the area with the same problem.

 

[stickboy1375]

It may already be bonded, stray is a funny duck, you can have the best bonding job and still have stray present, we have areas where entire developments can't use their pools because the stray current is high, the power company has been working on the problem for some time, short of re designing the local distribution network they tried additional grounding as some of the sub stations with limited success, some engineers feel the distribution return feeds are part of the problem, so if you bond and the problem continues, check to see if there are other pool users in the area with the same problem.

good video to watch....
http://www.mikeholt.com/strayVoltageVideo.php

 

[HughesBros.Electric]

i will try to bond the ladder and see if that will solve it. Thanks for the feedback guys.

 

[don_resqcapt19]

Are there any other electrical issues in the house? Voltage on the ladder only when something is turned on would have me thinking of a neutral problem.

 

[wirenut1980]

Could be a neutral problem. The problem may manifest itself with a large single phase load turned on, which a microwave is one of the largest in a house. A hairdryer would be another. This type of load would result in a larger than normal neutral current. 4 V does not scream to me there is a neutral problem or secondary fault. Proper bonding of the ladder should fix the problem.

 

[satcom]

Are there any other electrical issues in the house? Voltage on the ladder only when something is turned on would have me thinking of a neutral problem.

Yes it could be a local neutral problem and it also may be the return feed to the sub distribution needs to be sized up, he has some trouble shoots to do, and questions to ask

 

[don_resqcapt19]

... 4 V does not scream to me there is a neutral problem or secondary fault. ...

It does to me, if the voltage is only there when the microwave or other large load is turned on.

Proper bonding of the ladder should fix the problem.

It may make the voltage on the ladder go away, but it does not fix the problem.

 

[cowboyjwc]

Are there any other electrical issues in the house? Voltage on the ladder only when something is turned on would have me thinking of a neutral problem.

:thumbsup:

I wouldn't have a clue as to why it might be doing it though.

 

[wirenut1980]

It does to me, if the voltage is only there when the microwave or other large load is turned on.

It may make the voltage on the ladder go away, but it does not fix the problem.

I would agree if there was no voltage with the microwave off.

If I put 15 amps from a microwave on the neutral with a impedance of 0.1 ohms, that is 1.5 V added to whatever voltage is already existing due to primary neutral voltage drop. I think this is the more likely scenario. It would be interesting to see what the voltage measured is without the microwave on.

 

[satcom]

Mikes video on stray is excellent, I had an old westinghouse engineer explain it to me back in the 70's mikes video is right on.

Yes Don, locating the problem is not always that easy, one pool we had stray problems with turned out to be a boot leg neutral connection in a kitchen wall switch, some master hack installed recess lighting, and since there was no neutral in the switch box he ran the recess lighting neutral to the metal switch box (Bootleg) and when his daughter had her hair drier on, his wife felt the tingle in the pool.

 

[don_resqcapt19]

I would agree if there was no voltage with the microwave off.

If I put 15 amps from a microwave on the neutral with a impedance of 0.1 ohms, that is 1.5 V added to whatever voltage is already existing due to primary neutral voltage drop. I think this is the more likely scenario. It would be interesting to see what the voltage measured is without the microwave on.

I think that only the additional voltage drop on the line side of the main bonding jumper would show up between the bonded pool parts and unbonded parts.

 

[wirenut1980]

I think that only the additional voltage drop on the line side of the main bonding jumper would show up between the bonded pool parts and unbonded parts.

Nevermind,thought you said load side,not line side.

 

[goldstar]

Talk about stray voltage...check this news story out : http://www.chicagotribune.com/news/...irls-14-in-cornfield-20110805,0,2811411.story .

I'm not in Illinois but this should have been on news across tha states

 

[don_resqcapt19]

Talk about stray voltage...check this news story out : http://www.chicagotribune.com/news/...irls-14-in-cornfield-20110805,0,2811411.story .

I'm not in Illinois but this should have been on news across tha states

That was a step potential caused by a damaged 480 volt feeder. The fault current was not high enough to trip the OCPD but it set up a fatal step potential in the ground.

 

[goldstar]

That was a step potential caused by a damaged 480 volt feeder. The fault current was not high enough to trip the OCPD but it set up a fatal step potential in the ground.

Don, I didn't see any follow-up stories on this. If you have a link to news clip would you please post it. I can't imagine why this failure could not have been detected long before the tragedy occurred.

Thanks,

Phil

 

[don_resqcapt19]

Don, I didn't see any follow-up stories on this. If you have a link to news clip would you please post it. I can't imagine why this failure could not have been detected long before the tragedy occurred.

Thanks,

Phil

I don't have any links...the irrigation system feeder was damaged by lightning the day before and an electrician was on his way to check out the problem when the tragedy happened. At least this is what I have been told from some unofficial sources. I don't think we will have any firm details until the OSHA report is released 6 to 12 months from now.