33 millivolt NEV Reading At Service

Ravenvalor

Senior Member
Hello,

After reading Mike Holt's pdf titled 'How to Verify the Electrical System of a Pool is Safe in Accordance With the NEC' and watching his accompanying videos on this topic I decided to test the bonding system on a swimming pool for a subdivision.

Thanks for referring me to the pdf and videos in an earlier thread located here.

Here are the most interesting NEV readings.
First, I could only get a maximimum 33-millivolts between the service neutral inside the meterbase and a ground rod located about 20' away driven about 2' into the ground. The pedestal transformer was only about 50' away max and I made sure that my rod was not inbetween the service and the transformer. Maybe I should have driven the rod inbewteen those two in order to get a higher reading. I got a consistent reading of about 33-millivolts on everything that I tested around the swimming pool. A couple of water readings were 30-millivolts and one water reading was 26-millivolts but most of the water readings were around 33-millivolts.
I could never get a NEV reading on the concrete deck surrounding the swimming pool though. Neither could I get any continuity readings on the wet concrete deck even when the ohmmeter leads were about 6" away.
I checked the NEV on the 4 - underwater lights and they were all about 33-millivolts but that could have been the water reading and not the lights since they were submerged.
While I was out there I checked the resistance on the chlorinator equipment grounding conductor, the pump motor equipment grounding conductor and the pool equipment electrical panel equipment grounding conductor. Those readings were good.
There was an 'E-STOP' button on the fence about 10' away from the pool for someone to turn off the pump motor in the event of an emergency that I did not bother to measure EGC resistance. It was however in a pvc enclosure and fed by circuit conductors in a pvc raceway. There was also a swimming pool well being fed from the swimming pool electrical panel that I did not measure the EGC resistance.

That about sums it up. Thanks for the help with this and thanks for referring me to those videos. They are an eye opener.
 
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