2.5 Volts on Outdoor Shower

[Jimmy7]

First and foremost, I hope everyone has a Happy July 4th. In 2022, I upgraded my mother-in-law’s service in her single family home on Cape Cod to 200 amps. The soil here is a mix of sand because it’s a mile or so from the beach. In any case, we’re here on vacation this week and last night my son went to use the outdoor shower where he said he felt some tingling. This morning I put my meter on it and sure enough I got 2.5 volts ( From the faucet to the soil). When I did the service I drove two ground rods outside and then bonded the copper pipes inside, the water pipe coming in from the street is plastic. Is this voltage caused by a problem with the neutral? Could this be at the utility pole?

 

[MD Automation]

It’s possibly a utility problem.

If you are onsite, the first thing to do is see if the problem exists at the main – as compared to an issue w/ some branch circuit wiring.

Easiest test is to shut off everything at the main panel and measure both L-N voltages and L-L. You should see 120-120-240 (I'm assuming a typical single phase service), or something close to that, but hopefully pretty balanced between legs.

Then load up one side of the service with a decent current draw – toaster, hair dryer, shop vac. Needs to be a single phase 120 load. Then repeat those measurements above.

You are looking to see if you can get the Neutral to swing towards one leg. So the balance might then be something like 117-123-240. If that happens, you know there is a weak neutral upstream. Either right there in connection to the neutral bar, in the meter can, or the lateral out to the transformer.

If this test shows good balance between legs, then the problem is likely downstream in some branch circuit wiring.

If you do get the POCO onsite – a classic failure on their part is to pull the meter and measure voltages. And they declare all is good on their side and leave. Naturally, with no current flowing, the weak neutral problem is not "exposed". Either show them your test, or ask them to load the service themselves. A good lineman will have a “Beast of Burden” tester on the truck and know how to use it.

Good luck.

 

[ramsy]

When I did the service

I grew up in a college town, where neighbors rented out backyard auxiliary dwelling unit (ADU) hack jobs with outdoor showers for the college kids.

The makeshift ADU's are typically not sophisticated, so the showers come from an exterior hose bib, and outdoor & exposed Romex feeders get trampled underfoot with egress.

Looks like Cape Cod has several towns with colleges and universities.

 

[Jimmy7]

I have some more information. There is a utility pole behind house for the street behind the house (Not the pole that feeds the house). The pole has an abandoned temp service still hooked up plus a transformer at the top of the pole. I ran a wire from my house ground and the closer I got to this pole the higher the voltage got.

 

[Eddie702]

I have some more information. There is a utility pole behind house for the street behind the house (Not the pole that feeds the house). The pole has an abandoned temp service still hooked up plus a transformer at the top of the pole. I ran a wire from my house ground and the closer I got to this pole the higher the voltage got.

That's good troubleshooting. I would put an Amprobe on the GEC and see if you're reading anything. If you read something and it goes away when you kill the main the problem is in the house. If you have current on the GEC and it stays when you kill the main the problem is an outside source

 

[MD Automation]

Just to clarify a point I did not fully explain in my post#2...

What you are really looking for in my test is an increase in the L-N voltage of the leg you did NOT put the load on. There are various reasons why you might see a voltage drop in a circuit - but to see the voltage go up (with the L-L reading staying basically the same) ... that's a huge clue pointing to a weak neutral.

 

[Jimmy7]

The lineman showed up the other day and got the same readings as I did. He stated he will talk to his supervisor and decide what they want to do if anything. In any case, I have a question, if I wanted to do something about it could I treat it like a pool and bond everything together? There is one separate hose spigot and one shower stall. The shower stall has a wood frame with a hot and cold mixing valve. The shower stall floor is just pavers. How would you bond everything properly, a copper mesh grid under the pavers with #8 to the shower valve and hose spigot?

 

[kwired]

The lineman showed up the other day and got the same readings as I did. He stated he will talk to his supervisor and decide what they want to do if anything. In any case, I have a question, if I wanted to do something about it could I treat it like a pool and bond everything together? There is one separate hose spigot and one shower stall. The shower stall has a wood frame with a hot and cold mixing valve. The shower stall floor is just pavers. How would you bond everything properly, a copper mesh grid under the pavers with #8 to the shower valve and hose spigot?

that equalizes voltage between all the points you bonded together. It won't change voltage from those items to "earth". To do it like a pool you need to have equipotential bonding grid in the ground/slab in the vicinity of those other items you can touch at the same time to bring the surface you are standing on to same potential as well. keep in mind there will still be a voltage gradient at the edge of your grid area to regular "earth", the way to reduce that is to construct a "voltage gradient ramp" by making the grid gradually get deeper into the ground as you move away from the area you are intending to protect, then the voltage gradually falls over distance instead of a rapid ending at edge of the protection zone

Non conductive surfaces will help as well but water standing on them does increase conductivity of many items