Voltage difference between metal handrail and metal light [Swimming Pool]

[throwaway1]

Good morning everyone!

I have measurements from an electrician that measured 0.93V at the metal light casing and 0.33V at the metal handrail with their buildings and equipment in service. When they turned off their buildings in the perimeter and pool equipment, there was 0.62V at the light casing and 0.02V at the handrail. If this was grounded and equipotentially bonded, why is there still approximately 0.61V difference in voltage between the light and the hand rail? Shouldn't they both be the same voltage with reference to deck?

A couple of years ago, all of the primary equipment was replaced and the customer says it fixed the issue. A couple of years later they said it came back. What would have changed on the primary side? The residents of the pool have complained of a shocking sensation near the light.

 

[Dennis Alwon]

If the pool area is bonded properly the voltage should be the same in all areas around the pool. The equipotential bonding may not have been done well. It is certainly worth opening up the light and checking that the rails are bonded properly

 

[throwaway1]

The electrician is adamant it is stray voltage caused by the primary and that they have "verified" the bonding, but wouldn't a proper equipotential bond and ground mitigate this issue?

 

[don_resqcapt19]

If they are actually bonded together, there will be no difference in potential unless you have enough current flowing on the bonding system to create that much voltage drop.