Electrical ground and plumbing ground

We had this new faucet installed, it’s a Grohe Ladylux Touch. It’s the kind where you touch the faucet and it turns the water on, touch it again and it turns it off.

OK, here is the pre-ample to the problem. The sink installed is stainless steel. If you touch the sink any place on it, it acts as if you touched the faucet and it turns the water on or off. This is not desired at all.

When I first talked with Grohe support about this, they told me to remove the ground from the sink and connect it to the ground that the dishwasher is using. That was done, but it didn’t solve the problem, if you touch the sink it activities the faucet still.

Now for my questions…

There is electrical ground and then there is plumbing ground? If so, isn’t the ground for the plumbing and the electrical connected together? I asked this, because it seems like the two grounds are joined considering that touching the sink still triggered the faucet even those it was connected now to the outlet box for the dishwasher.

Should electrical ground and plumbing ground be joined together? If not, how should it be done?

Is there an easy way to create, a separate ground that isn’t shared with the plumbing? Because it seems that somehow the sink being connected to the plumbing is also sharing the same ground as the electrical.

Theres’ no such thing as a “plumbing ground.”
Plumbing may be used as an electrical ground. (I am not commenting on whether this is a good idea or not).

I would see if the faucet has an insulating gasket that is missing. The faucet should be electrically isolated from the sink.

In the old days, it used to be required that you used the cold water pipe as your home’s electrical ground, since pretty much every home had a cold water pipe coming into it. So on old homes, the entire electrical system will ground through the cold water pipe.

When PVC pipe started to become common, folks realized that the cold water pipe was no longer a reliable thing to use for your home’s ground. So now, homes are required to be grounded through a separate grounding rod (literally, a copper rod driven into the ground). However, you don’t want your plumbing to “float” electrically, as an accidental short to the plumbing could cause all of the pipes to become electrically “hot” and create a shock hazard. So your plumbing system is still required to be connected to the earth ground. Connection-wise it’s the same. You still have a connection between the neutrals and your plumbing, it’s just that the reason for it is backwards. Instead of the plumbing being the ground, the plumbing is being grounded.

This is required by the NEC, which most places use as the basis for their electrical codes.

If you have an older house, there is no requirement to update the grounds so that you are using a separate grounding rod. However, if you replace the metal piping with plastic, then you need to run a ground wire over to the remaining metal pipes. Similarly, if you “upgrade” parts of your electrical system, then generally any part that you touch has to be brought up to modern code.

By the way, just for clarity, this is what your problem is.

The grounding of the plumbing is required by the NEC. The problem isn’t that the sink is grounded (it better be, or you have a bigger problem). The problem is that the faucet apparently expects to be electrically isolated from the sink, and apparently isn’t.

There is quite a lot more to NEC 250.104, Bonding of Piping Systems and Exposed Structural Metal.
To the OP, I suspect that your problem is simply that the faucet and basin are in electrical contact with each other. Regardless what else they are connected to, touching the basin is always going to be the same as touching the faucet, if there is no insulating fitting between them.

By the way, one more thing. I’m not sure what “ground” means in this context, but if it refers to an electrical safety ground, you CANNOT use the plumbing as your safety ground. If someone actually wired the safety ground to your plumbing then I would have an electrician come out to see what else they did wrong, because they clearly had no idea what the hell they were doing.

Not being very plumbing-savvy I wonder - how do they do that nowadays, with non-conductive material on both the feed and drain lines?

I have an inspector-approved bathroom sink where the drain is through PVC and the water comes in on those flexible plastic pipes. (Part of the sink drain fitting is metal.)

Or are they just requiring that any part of the plumbing system that is metal must be grounded?

Basically this. Any metal parts have to be grounded so that they can’t float and accidentally become a shock hazard.

I do hope (after the OP gets his faucet electrically isolated from the sink), that someone will explain ‘bonding’ of remote electrical devices to the rebar in a swimming pool.

I could understand this when the drain and return lines were steel, but these lines are PVC and certainly NOT going to conduct electricity.
And I’m not certain that connecting a pump (which could, conceivably, send a current down the bonding line) to the, say, (metal) niche lights and into the pool water, is such a good idea.

Nonetheless, I have dutifully connected bonding lines as well as ground lines, to the pumps i installed,

I’m just wondering, from an electrical standpoint, WHY I did so.

My suggestion is go to the hardware store and get a sheet of neoprene. Pull up the faucet (I know, it sucks), make the approtiate holes in the neoprene (smaller then need be), reinstall the sink and trim the sheet to size*. This should isolate the faucet from the sink.
Short of installing a non-conductive sink, I know of no other easy way to fix this problem. My whole house is grounded. The only way to eclectically isolate the faucet would be to install some pex between the shutoffs (after the dishwasher tap) and the sink. But even that wouldn’t work since the disposal is probably grounded and electrically (WRT the sink) connected to the sink.

IMO, finding a way to isolate the faucet from the sink is probably your best bet. I think a sheet of neoprene, carefully cut to size is at least worth a shot. You might even be able to leave the plumbing connect and just loosen the nut(s) that hold everything down and slide it in place. The question is going to be if it shows and if it bothers you that it shows.

I’m also guessing that you’re going to have this problem with any similar sing unless they include they’re own workaround gasket/plastic piece to do it for you.

I’m not exactly what you’re asking (because I’ve never worked with pools), but this would make sure that the rebar* and the pool pump (if it comes in contact with the water) have a potential of zero, since they’re electrically connected. The idea, I think, is that if the pump shorts to the water the rebar will provide a path to ground (if the pump doesn’t ground it first. Also, any lights or even a radio falling in, have a ground path. It’s just one more safety precaution to keep the pool from becoming electrically hot. It’s an easy thing to do while building a pool. Honestly, even, just driving a few of the pieces of rebar a few feet into the ground and tieing them off to the mesh would work as well.

*I’m guessing this is in case the outside of the pool is lines with plastic so concrete itself can’t act as a ground.

When I was young, I built four 100 Watt amplifiers from kits. There were various problems, 60 Hz hum being one. I connected some cheap, very inexpensive speaker wire to the chassis, ran it out my bed room window and wound bare wire around the water hydrant. All was well. A month or so later, when watering the lawn, I saw that the insulation near the hydrant had melted and the wire was charred.

I had some 60hz hum on one of my TVs, never could get rid of it. I did everything I could come up with to eliminate it. But it sounds like you had way more then a little ground leak…like I’m surprised you didn’t get a shock at some point.

Mama’s house was built in 1955 with two conductor outlets. G-d knows what was going on.

But Smoke on the Water and* Der Ring Das Nibelugen* sounded cool as hell with 400 Watts. :slight_smile:

While I consider myself fairly well versed in DIY stuff, I’ve never worked on a house with no ground. So I can’t speak to that (but I probably would have connected it to a water pipe). Did you get rid of the hum? I never did, I even picked up a power conditioner, made sure the entire entertainment center was on the same outlet*, bonded all equipment with a copper wire and electrically connected all the coax splitters in the house and grounded them to a water pipe. There should have been no loop.

*Come to think of it now, the network gear is ungrounded, so maybe it was that. I never thought to unplug it all and check then. As I’ve upgraded all my equipment, it’s gone now, but it was really annoying to watch bars rolling up the TV.

Yes, Brunhilde with dynamic range! :slight_smile:

Update: Thanks for all the replies. It got me thinking and I also talked with Grohe technical support on this. Support had me remove the battery and adjust settings to basically reset the control box for it. That didn’t help. I was also told to place ground from the control box (for the Grohe touch thingy) to the stainless steel sink, then the plumbing and finally not connected to anything. None of these things made any difference. So that convinced led me away that this isn’t a ground issue at all.

Technical support did come to the conclusion as some of you did here, that somehow the sink is connected to the faucet touch part. Which is why when you touch the sink, it behaves as if you touched the sensor on the faucet. Technical support said I should the plumber who installed this back out there and have them talk with technical support to resolve this, because they believe it was installed where something is making a connection.

After the phone call, I remembered that I have an electrical continuity tester. For those that don’t know, it’s a simple device operated by batteries which there is an alligator clip at one end and a needle-probe at the other end. If you touched it to itself, the light comes on and that shows you got a “continuity” meaning there is a connection. OK, so I took the continuity tester and touched it to the part of the faucet where it would activate the sensor and the other part to the sink, and bingo, the light came on! To me that confirms there is a connection path going on somehow.

Now the real issue is what the hell to do about it. The counter top has a stainless steel under mount sink. Looking under the sink, you can see that the lip of the sink extends out about an inch or so. I tried the continuity tester with the soap dispenser which on the other side of the where the touch faucet is installed and that test failed, the light didn’t come on. No surprise there, because I could see in that area that the lip of the under-mounted sink wasn’t touching the soap dispenser.

However, where the faucet is, it is much harder to tell. I stuck my iPhone under there to take some photos and it doesn’t look like any part of the lip of the sink is touching the faucet but I can’t be absolutely certain.

With so much focus on if it was touching the faucet, I wonder if it might be getting there another way. There is a InSinkErator batch feed garbage disposal installed and I can’t help from wonder if the metal from the sink touching the garbage disposal is coming in contact with the plumbing water supplies and eventually leading up to the faucet.

As you can imagine, this is frustrating. Certainly people have used these products or type of products in this configuration without a problem. Technical support did ask me several times if there is a black plastic ring under the faucet that can be seen on top of the counter. And it is there, because tech support it’s behaving like it isn’t. It is there and installed correctly, well, it had to be because I recall when the plumbers installed this that black plastic ring was part of the whole thing and no way to remove it.

There could be something else under the counter from the faucet that wasn’t installed because the part was missing or the plumbers simply didn’t install it, I don’t know. But I don’t know if that is the source of the problem or not.

I do have a reason for the same plumbers to come out for some other work, and I could bring it up with them there how it is not working and what I found it. Maybe they can find a way to easily do something to isolate it. They might have to re-installed the faucet just to see what is going on, of course, in the end it could be the garbage disposal and in that case how can they possibly isolate that from the sink while it still works with the sink?

The sink is connected to the faucet, period. The disposal shouldn’t play into this at all. Just looking at a picture of the faucet and very, very quickly glancing at an installation video it appears they do what they can to electrically isolate it from the sink. Rubber/plastic grommet between faucet and sink, plastic nut under the faucet, plastic supply lines to the valves. However, I do see one thing…they have SS hoses that connect to the actual faucet. Check to see if any of those are touching the sink (or the threaded base of the faucet) is making contact with the sink anywhere.

You said you have a multimeter, set it continuity, take the battery out of the faucet, disconnect any electrical connections, attach the probes to the faucet and the sink and then move the supply lines around and see if you can get the resistance to go from 0 to infinity. If you’re sure the supply lines aren’t touching anything (including the disposal now that I’m thinking about it), try sliding the faucet around in the hole to make sure the brass threads aren’t touching the SS.

If you really want to go all out, you could remove the nut from under the sink, lift the faucet out, make 100% sure any stainless or copper supply lines aren’t touching anything and then touch the sink…I’ll bet it doesn’t turn on*. In that case, you’ll know it’s the faucet making contact with the sink.

*Of course you’ll be making the connection at that point, so put on a glove or hold it with a dry towel or something.

One wonders if the plumber left any of these off. Can the OP check to see if they are present?

Just looking at a picture, I can see a big black piece of plastic meant to insulate the faucet from whatever it’s mounted on. Is that there on yours? As for everything else…
1)You can’t really substitute the nylon nut underneath, but you can check to make sure it’s nylon and not metal, but I’d be surprised if the plumber was like ‘well, I’ve got my own, I’ll just use this one’.
2) Check all the stainless steel supply hoses, make sure none of them are in contact with the sink or disposal
3)Um, no three yet, start there.

ETA, if that piece of plastic isn’t there…if your faucet is directly mounted in your sink, that’s your problem.