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View Full Version : Ground for a dishwasher, two wire, install rod in cellar?


porlalps
Sep 18, 2010, 05:58 AM
Hello, I think I may have confused myself reading some of the other questions and answers and would like some clarification.
The house in question was built in 1839 and is a stone built farmhouse in the French Alps. It has a distribution box, below which is the meter and then a single breaker marked 2 phase 30A.
Frankly the whole place is a wiring nightmare, everything is either buried in walls or in some kind of conduit. Eventually when the whole place is rebuilt this will be put in order with a normal panel etc.

I have an outlet behind where our cabinets are and where the dishwasher will be going, this outlet has two wires going to it, neutral and hot. I've tested the dishwasher all is fine, except when touching the casing of the dishwasher you get a slight tingle, this is sporadic and seems to depend on how much other stuff is running.

I have galv. Steel water lines which will be used to plumb the dishwasher nearby. These lines run about 2 feet into the basement and then about 18ft along the ceiling to where it connects to a rubber supply pipe.

My thought is to run a ground wire from the outlet and clamp it to the cold water line, then in the basement where the water pipe comes out, clamp another ground wire to the pipe and run it the 6 feet to a ground rod driven into the floor. The floor is dirt and rocks, lots of big mountainy rocks!

There is no way at all of bringing a wire back to the supply at the moment. Will this solve the tingling? And is it safe, or at least safer than what we have?
Thanks in advance.

Stratmando
Sep 18, 2010, 06:10 AM
You say an Old Farm House in the French Alps, Sounds Very Serious, I need to get there right away.
I wish.
Depending on the Pipe, You may end up energizing the whole pipe.
Their may be something within the dishwasher making a connection to the case making it live. Hard to say without being there.
I would wait for addition info.
Good Luck

stanfortyman
Sep 18, 2010, 06:22 AM
I have galv. steel water lines which will be used to plumb the dishwasher nearby. These lines run about 2 feet into the basement and then about 18ft along the ceiling to where it connects to a rubber supply pipe.

My thought is to run a ground wire from the outlet and clamp it to the cold water line, then in the basement where the water pipe comes out, clamp another ground wire to the pipe and run it the 6 feet to a ground rod driven into the floor. The floor is dirt and rocks, lots of big mountainy rocks!This is NOT the "ground" you are looking for.

A ground rod or pipe electrode is not, and cannot be, a circuit ground.
The water pipe sounds very sketchy and may only be used as an equipment ground in VERY specific cases, in the US at least.

As Strat said, you may very well be creating an even more dangerous situation by connecting a ground wire to the pipe.

porlalps
Sep 18, 2010, 06:52 AM
Hi thanks for the answers so far, and I think I'm getting things a bit more straight. I realize this wouldn't be up to US code, but I'm not in the US anyway and also to put this completely correct would require a total rewire and change of supply, more than we can do at the moment.
Strat... I can understand why you'd want to rush over! I'm originally from St Pete FL and moved here just a year ago, I do not miss the humidity one bit!
I did check the wiring inside the dishwasher, all the wires are connected to the correct terminals and the ground connected to the body as from the factory.

Do you have any other suggestions assuming that I cannot get a ground wire back to the supply.

Stratmando
Sep 18, 2010, 09:18 AM
If you have a Multimeter, you could look for continuity between the ground and incoming supply wires, on Dishwasher.
I remember when I was a Kid playing a pinball machine and got shocked, I unplugged and plugged in backwards, and the shocking was gone, this was before many plugs were polarized.
I still think I need to get there right away, will bring a Meter and Skis. Take Care

hkstroud
Sep 18, 2010, 07:59 PM
I realize this wouldn't be up to US code, but I'm not in the US anyway
Does electricity behave differently in the French Alps?

I would think you would want to find out why you are getting shocked and fix the problem.

porlalps
Sep 19, 2010, 12:38 AM
HK, I don't think it does, I only mentioned US code and not being there because I 'm pretty sure any advice adapting this situation would be just that, adapting (read rigging). I believe the problem is that there is no ground wire in the outlet, so when I plug the dishwasher in the ground is the case of the dishwasher as this is where the ground terminates. Also this is not a shock, more a light tingle, like static, I would only feel it when I was kneeling down next to the machine while working around it, my rubber shoes are enough to stop the feeling.
Will check the continuity as advised.
What if I were to eliminate the water pipe from the equation and run the ground wire directly to the ground rod in the cellar?

stanfortyman
Sep 19, 2010, 04:52 AM
I believe the problem is that there is no ground wire in the outlet, so when I plug the dishwasher in the ground is the case of the dishwasher as this is where the ground terminates.Absolutely false. The case is NOT the "ground". The case is becoming energized by a fault. It is not grounded or bonded so you are feeling this tingle.





What if I were to eliminate the water pipe from the equation and run the ground wire directly to the ground rod in the cellar?Please read replies #2 & #3.

hkstroud
Sep 19, 2010, 05:00 AM
Sorry but a tingle is a shock, just a mild one. More importantly, it a sign that you are in contact with electrical current somehow. It is only a tingle or a mild shock because you are not very well grounded. With rubber shoes on you are not grounded at all. When kneeling you are probably grounded through the moisture of the stone floor. Poorly grounded granted, but enough for electricity to pass through your body.
What will happen when you touch the dishwasher and your water faucet or some other well grounded object.
If you successfully ground the frame of the dishwasher you will probably blow the circuit. Grounding is just not the way to try to fix the problem.
The problem is that the frame of the dishwasher is in contact with electrical current. That could be with in the dishwasher itself or it could be through the metal piping. It could be faulty wiring in contact with the plumbing. If the electrical system ground is also connected to the water piping system as here in US, it could be the lack of a proper ground rod or a poor connection connection in that system.
You also said,
this is sporadic and seems to depend on how much other stuff is running.
To me that indicates that there is possibly a fault on the neutral side of the "other stuff".

I would start by disconnecting the dishwasher and checking for continuity between the dishwasher wiring in the connection box and the frame of the dishwasher with a sensitive meter.
The way you describe the water piping it sounds like your piping is in contact with the earth but just barely. I would also check for voltage between the piping and a known good ground.

Stratmando
Sep 19, 2010, 07:18 AM
Try turning off power to the Dishwasher and see if voltage is still present.