we would get mild shock when touching the shower faucet but the cause was a failing element in our water heater. Replaced it and problem stopped. we do not have heated floors. So ck heater also.

The water heater is 1 year old and gas - and the problem started with the heated floor and went away when we turned off the heated floor. So I'm pretty sure it's the heated floor in our case!

Is your outlet grounded properly? Google stray voltage also. Several horses in abuquerque at a racetrack were electrocuted from stray voltage.

Can you run a test on the GFCI at the thermostat?

After my tub surround was constructed, I experienced the same thing you are. There was an electrical plug in the bedroom on the wall shared with the bathroom, located right behind the bathtub at the rear of the tub (not on the valve wall). Turns out the wire there was nicked by a staple during construction of the surround. It was accessed and repaired by opening the wall in the bedroom.

Was a new electrical circuit run for the in-floor heat? Probably was...so...

Find out if an electrician did the work. Or if it was "someone who knows about electricity" that did the work.

I'll ramble for a bit, but with a "new problem" occurring after "new work" was done? It's likely something that was done with the recent work, which is obvious. But sometimes old work can be disturbed so I'll offer a laundry list.

Troubleshoooting can be started by isolating the faulty circuit, then examining the loads on that circuit. The electrician can turn circuits off until the symptoms disappear. Then troublshoot the faulty circuit.

I'd start by taking a look at the thermostat itself, make sure the T-stat itself is working properly. Make sure the t-stat wiring is made up correctly. Neutral, ground, hot wires, line, and load...no switcheroos, nothing backwards. Same in the panel. That the new wiring is connected correctly. Neutrals, grounds, hots. Proper box/romex clamps used where the wiring enters the service panel.

The wire runs off the t-stat, down the wall, and into the floor. Where that wire goes from the wall to the floor, that can be a pinch point. If a metal plate wasn't used on the face of the sole plate to protect that wire, it's possible a drywall screw might have caught it, or perhaps a nail when the baseboard or other trim was installed.

These things can sometimes be the cause of a disconnected or mis-connected neutral or ground. I'd have them run through the service panel, checking the connections that have already been made. Check that all ground and neutral wires are to their respective bars. That any jumpers in the panel are still in place. There's a possibility that when the new work was done, something in the old work was accidentally disconnected.

Not sure about your house, but in some houses, the water supply tubing
itself is grounded. If there is one, ask them if the plumbing ground was broken/disconnected when work was done. Sometimes
the ground wire itself might have been disconnected, sometimes a part of the copper plumbing
run becomes ungrounded when a non-metallic fitting is added to a run of
plumbing, breaking continuity.

If a non-conducting piece of plumbing was added, a grounding jumper should have been installed across that piece to maintain the continuity of the ground.

If your in-floor heat is 240V and basic 12-2 romex with a black and a
white wire was run, I've seen the white wire incorrectly marked
(insulation left white instead of being recolored as a "hot" conductor)
and incorrectly wired as a result.

The water heater itself can be turned off to isolate that as a problem. If the problem comes and goes
as the water heater breaker is opened and closed, it could be an issue with that circuit.

It could be a fastener that was driven too deep into a framing member, with the fastener nicking the electrical.

I've seen one short where romex touched copper tubing because the installer ran romex and copper through the same holes in the framing and the romex insulation was worn through.

I've seen romex in contact with copper, with the romex insulation melted from conducted heat when copper tubing was soldered.

Quite a few opportunities for failure. A lot of mumbo-jumbo in my post. I've thrown a lot of mud at the wall so to speak. An electrician should be able to troubleshoot and diagnose effectively. "Someone who knows about electricity"? Maybe not so much. And FWIW, I'm not a licensed electrician. So I myself fall into that latter category.

In the meantime, don't use the shower. A "tingle" today can turn much worse tonight.

Good luck with it.

We did not get a shock when the heated floor was turned off at the thermostat, so it seems tied to the floor heat. There is a GFCI test button on the thermostat but I'll let the contractor/electrician check that when he comes - I don't feel like turning it on again to mess with it.

I do not know if the electrical guy is a licensed electrician, I will have to ask the contractor.

There IS actually an electrical outlet on the other side of the wall, in the bedroom. So it's not true that there is NO electric in that wall, I just realized.

I really hope this issue is easy to fix and fix without ripping out everything that was just done. We just moved back in, have cats that need to be kept closed up during work, and we both work FT so it's really going to be a nightmare if they have to rip open any walls or rip up tile.

I watched the install video - it's really a DIY product - and the mat was NOT cut.

https://www.youtube.com/watch?v=Y9Cp8bua2Eg

tmnca, FYI when the wall needed to be opened up to repair my nicked wiring, it wasn't a big nightmare. Inconvenient, yes, but nothing in my new bathroom install needed to be disturbed. Just a little drywall patching and paint repair in the bedroom.

Maybe that plug on your bedroom wall shares an electrical circuit with your radiant floor heating? If something is wrong with the GFCI, you could get a shock?

" ... and the mat was NOT cut."

If a razor knife was used to clean excess thinset out of the joints of the tile before grouting, it's possible the radiant heat mat could have been nicked.

jellytoast, thanks - and yes you're right damage to the mat is one of the possibilities we have to consider. I just meant it wasn't trimmed to fit the room, which is the only case in which the directions say to tape it - the mat is a self contained sealed mat unless trimmed - or cut unintentionally.

The contractor said the bathroom has it's own GFCI circuit and not shared with the bedroom, plus the thermostat has its own GFCI test button. Testing that is of course on the list, but I am not planning to turn the floor back on myself!

Good luck. Please let us know the result!

The contractor is contacting the manufacturer tomorrow to see what their suggestions are for most likely cause, and then they are coming to check (and hopefully fix) Wednesday.

Update - it turns out that the mat does not have a ground wire, and the upstairs plumbing is not grounded. They tested when the heating mat is on there is not only current in the shower plumbing but also in the other bathroom plumbing and every metal fixture upstairs. All downstairs plumbing is fine. They found there are ground wires on the copper pipes running to upstairs, but there must be some non conductive material in the walls (maybe a flex elbow they said). So grounding the upstairs plumbing is apparently step 1.

Any thoughts on this?

Your mat is leaking electrical current. You get a shock because your body is completing the circuit between the electric (at a higher potential) and the water pipe (at a lower potential). Grounding the water pipes will do no good. The 'leakage' - where the mat is damaged / missing insulation needs to be fixed.

OMG, remind me to never get underfloor heating. I have a terrible shock phobia and just the thought of this happening gives me the willies.

Be aware that simply grounding or bonding the upstairs plumbing isn't going to completely solve the problem. It may just mask the problem and still leave you with a dangerous installation.

Some how the mat's electrical circuit is leaking current. Your electrician can run the numbers for your mat and measure to see if the mat is damaged. Your mat was a single mat installation and it was not cut down in size. That should make the numbers easy to run.

I run a resistance test on the mat right out of the box to see if it is defective from the factory, it also gives a baseline ohm reading. I also run one after it is thinsetted down, after the tile is set, and after the tile is grouted. These steps let me know if the mat is damaged during any step of the installation process.

They can also do an expected current calculation and see what is going through the mat. You could be losing electricity before or after the thermostat. If before, the wiring can be corrected. If after, it's probably a rip out to replace the mat, or you cut the leads, cap them, and abandon the installation.

Shouldn't the GFCI be preventing an electrical shock?

I know someone whose mat was damaged during installation. The manufacturer sent someone out who pinpointed the area where the mat was damaged and it was repaired in place without having to tear out the entire installation.

I'm right there with you, Linelle!

geoffrey_b, yes I agree with you the mat must be leaking current in order to produce this effect. Grounding things is not an acceptable remediation. Unfortunately the cost of materials is so low compared to the cost of installation. I imagine if we go further with the troubleshooting we will reach a point where it's impossible top prove whether the mat is defective or if it was damaged from install. The contractor was present when mat was installed and claims it was not damaged. The manufacturer is unlikely to warranty anything without proof of that which would presumably entail removing the floor. I think we want the contractor to finish the kitchen work (install sink, DW hookup and backsplash) and then we'll have them cap off the system and abandon it. It's on its own breaker so it's not a risk right now. I will not expect to be charged for the install, I can return the thermostat and I'll be out $200 for the mat itself worst case scenario. If I need to get an electrician in there to separately confirm that it's most likely an install issue (ie if contractor charges me for install), I will.

jellytoast that's what I said - GFCI should be shutting the thing off! Maybe the current leak isn't enough for the GFCI to flip? It's a mild tingle not a serious shock. Still very scary.

I would not give up so easily. There are procedures that when followed, should produce a quality install. They are in the business of making this happen. They should fix it. If you buy a car, and the radio doesn't work - do you ask for the money back on the radio? No - they fix the problem. Don't assume that they have to tear out the entire floor. But if they do - it's their dime. They are learning.

As I mentioned earlier in the thread, I know someone who had their mat damaged during installation ... a wire was cut. The manufacturer sent someone out and they were able to determine exactly where it was damaged and it was repaired in place without disturbing the entire floor, just one piece of tile. It was not covered under warranty, but the cost was quite reasonable. I would call them first before giving up.

I've heard that not allowing the thinset to fully cure (for 2 or 3 weeks?) before heating the mat can cause problems. Not sure what those problems are or if that happened on your install ...

It's not just about the money, we are now moved back in to the home, we are both busy and work FT and don't have time to deal with another disruption and huge mess, after we just got everything cleaned up from the renovations. Ripping up tile and mortar and redoing it is not something I want to deal with whether on their dime or not... unless they can pinpoint it to remove only a tile or 2 or something. But, yes, we will talk to them about this after the rest of the work is completed. My priority now is plumbing hooked up in the kitchen and BS & range installed (counters went in today) so we can start using it and stop eating out every meal!

jellytoast, I sure hope so! The contractor is working with the manufacturer to troubleshoot - that's how they came up with this grounding thing, which doesn't inspire my faith since I know enough about electricity to know that's closing the barn door after the horse escaped. I don't have much faith though it seems like the manufacturer (TEC) is unlikely to put too much into a diagnostic over a $200 product.

hi i just put in the same product and am having the exact same problem! only when the floor is heating do you get a tingle. what was your outcome?

kids1313 I am sorry to hear that! Our contractor spend some time trying to troubleshoot on the phone with the manufacturer, who tried to blame everything except their product. We decided to cap off the wires and remove the thermostat because we just do not want to deal with having any more work done on this house - I am 6 months pregnant and do not want to deal with this kind of thing right now. The contractor did not charge us for the install, troubleshooting or return trip to cap off the wiring.

I plan to return the thermostat at Lowes and make an argument for a refund on the mat as well (obviously not pulling up our tile to remove it for return!). I will let you know what they say but I plan to make sure they know their liability in this issue, and it's interesting to know that another customer has had the same experience with the product. Have you lodged a complaint with the manufacturer?

hi. thanks for responding. i called tec earlier today. they sounded concerned? they are sending me documentation to fill out. stay tuned.

well. the short and long of it is this. tec is telling me that the ingredients in the cement beneath and above the heat mat is causing moisture that needs to dissipate. that moisture is coming up through the tile into the water and into me causing the shock. we need to give approx. three weeks more for it to dissipate. let's see.

kids1313-

I think that is a bogus explanation, and a dangerous situation. The heating elements should normally be insulated from moisture and, if you are getting current leakage and shocks/tingles of any kind, that is a defect in my opinion. Even if the situation would improve after things are left to dry, that still suggests that there is a current path that could occur at any time, and possibly get worse in the future. You need a safe solution: you either need to get this fixed or to disconnect the wires.

kids1313;

I would concur with kudzu9. Since this is a bathroom how can you possibly escape moisture. The insulation appears to have a breach somewhere. I would not accept the explanation you have been given, This is a dangerous situation with a live circuit

" tec is telling me that the ingredients in the cement beneath and above the heat mat is causing moisture that needs to dissipate."

According to TEC's installation instructions:

8. Do wait a minimum of 28 days after installation before you turn system
on. Refer to mortar manufacturer’s guidelines.

I assume it's past 28 days.

hi. you are right. also, i was wondering why i was not getting shocked when i touched the other faucets, on the tub and sinks. i figured out that the connections from the pipe to those faucets are done in pex pipe, which is plastic and therefore is non-conductive! the shower plumbing is all metal pipe, therefore providing the ground that the floor is looking for. stay tuned.

Something you may want to consider is too have an electrician check the outlets in the bathroom to ensure they are properly grounded. This requires a special tester called a megger or insulation tester. Without trying to scare you there were multiple cases of soldiers in Iraq who were electrocuted in the shower. What happened was the contractor responsible for setting up the showers were not checking earth ground integrity. While there is some moisture in the thin set used to lay the tile which may cause some leakage I would check to ensure the safety. In Europe they have to test for grounds when performing work. Not all electricians have a megger, so you will have to check to ensure they are able to perform this test. You can search on YouTube for electrical insulation testing to gain a little more insight.

Yes it's baloney that allowing mortar to cure would remove risk of electric shock, that recommendations is to prevent buckling etc of the tile and mortar if too much heat is applied during curing. Current should not be getting out of the mat, period there will always be moisture in bathrooms and moisture in the tile grout etc in a bathroom is always a possibility. The product is defective!

Yes all our electrical was tested, and our electrical is fine - it is not the problem. They tested all the grounds and also tested the plumbing fixtures in both bathrooms (sink faucets and shower fixtures). The shocks/current only occur when the heated floor was turned on.

I'm going to Lowes tomorrow AM with my receipts - wish me luck!

Is there an organization I can report the safety issue to, regarding the product itself?

tmnca-

It may not be a defective product, but a defective installation. Good luck. Please update on what kind of response you get.

tmnca; good luck with a refund. I am not sure how they will provide you with a refund on the tile work you paid for. Pls let us know the outcome. I had a bad experience with Lowes in our area. Through personal experience I have discovered a 90% chance they will not have what I am looking for. However, they are closer. The employees who are suppose to load your vehicle hide out hoping the customer will load their own. After the third load I was not about to let them get away with it again. I made my presence known :-)

what happenned with lowes? i am still waiting.

still waiting to see if cement cures and resolves the issue that is.

kids1313-

This is a defect, and a dangerous one at that. Curing cement is not going to resolve the risk. If the shock is reduced or not in evidence immediately after everything dries out, it doesn't mean that it's fixed. Electricity is very patient in waiting to electrocute you...

kids1313, what was the resolution with this? thanks!

Exactly the same issue here - TEC from Lowes, only when heat is cycled on. This thread has been very informative, thank you. In our case two mats were used and cut to fit and it's on it's own circuit to the breaker. We waited over a month to turn on the heat after install. The shower install was a multi-piece and we have CPVC feeds but then copper from the mixer to the various heads. We have run a dedicated ground to earth which helped but not stopped. Working our way through it. Today will ground all the various pipes, track the romex to make sure it's grounded properly and check the thermostat wiring. If that doesn't fix it we have a much bigger problem. How can voltage leak in the mat traverse thinset, concrete (shower base), grout, and stone tile to complete the circuit to ground? Has anyone that did this install manage to fix it without pulling up tile?

Glad I went with the Schluter heated floor. A bit more money but none of these problems.

In case anyone is interested - I had the same problem as described above. I contacted TEC and they offered to pay for an electrician to troubleshoot the problem (June 2018). We found that we could ground the drain to the shower from the basement to remove the 55 V potential in the floor so I did that and thought it was all taken care of, if only a band aid solution masking the problem. Fast forward to October when I actually turned the system on for the season: I got out of the shower and stood in front of the vanity. As soon as I touched the faucet (or running water) while standing on the floor with wet feet, I felt the same tingling as I used to get in the shower. Quick check with a multi-meter showed 55 V between the grout lines in the tile floor and ground, and this only occurred when the system was actively calling for heat.

I contacted TEC again to see if they had any further input. They couldn't come up with anything so they offered a full refund of the mat, the thermostat, and any installation extras like wiring. This totaled about $500 because my bathroom project was pretty small (15 square foot mat). I considered accepting this offer, but I had spent a lot of time installing the product and had done so exactly to specifications. I didn't do all that to not get a heated floor. Furthermore, I noticed around this time that the product was no longer available anywhere. I contacted support again and requested reimbursement for a full replacement of the floor, including all tile, a new heating system, and the labor to have someone else do it for me. I did it once myself - I have no desire to rip out a tile floor and do it again. With what amounts to essentially no evidence from me, besides the opinion of the electrician, HB Fuller (owners of TEC brand) agreed to $2440 to have someone do this for me. The re-installation is currently scheduled for mid January and I have already received the full amount for it. Overall, I'm very disappointed that I have to go through this, but I'm pretty impressed with their technical service and product support. This is a pretty low price to get out from under this for them - I'm sure it would cost much more for a larger bathroom or kitchen project, and I hope no one was hurt because of this fault.

Thanks for the update. An unfortunate situation and I'm glad you're getting it dealt with properly this round. The band-aid solution is not one that would have made me feel safe. I am impressed that the company stood up and provided you réstiturion.

Dear Everyone with this problem!

I have the same problem in Hungary as Tmnca has. After installing film electric floor heating in our house, we experienced electic shock when touching shower fixture while electric floor heating is on in the bathroom. Has anybody a magic solution for this? What do you know about our rights as getting compensation. What the installation company must do in this situation?

Thanks for every promising words or solution, we are very hopeless after some tries.

Best wishes,

Tamas

Dear

@kids1313

@HU-542723787

@Tmnca

@Nick!

Do you have solutions for your electric shock problems? I would very appreciate your help, because I have the same problem, and I am very hopeless for solving this issue.

Thanks,

Tamas

V. Tomi-

Shut off the breaker that feeds this circuit before someone gets injured or killed, and get an electrician in to see if it can be fixed. If it can't be fixed without tearing up the floor, the electrician should be able to disconnect it to prevent this hazard without affecting anything else on the circuit.

Tamas,

I'm sorry to hear you are also having this problem. It seems this product is defective by design (and the company knows this) which is why it has been completely unavailable in the US since the middle of 2018. I don't believe there is a way to fix this besides removing the system and totally replacing it. Obviously this is costly and labor intensive - see my post above for what happened in my case - but a master electrician coupled with the company's technical support could not determine a feasible solution. I reached out to HB Fuller directly and received acceptable compensation. This may be your only course of action at this point besides taking legal action. -Nick

I am sorry to hear others have had this problem and it’s outrageous that it’s been sold Even after my report to Lowes. They only refunded me the thermostat which was removed BtW didn’t even give me store credit for the faulty mat because they said unless I removed it and returned it i couldn’t prove it was not an installation issue.

I did not have the time to pursue any further complaints on the product, I wish others better luck!

Thanks for the answers! Best wishes!

Hey, I have the same problem with my heated floor. When it's on, it shocks, when it's off its fine. When I have the outlet torn apart, and all the wires clearly not touching anything, I turn it back on and it shocks again. Very mild. I see three possibilities with my situation. 1. I knicked the wire in the wall and I cannot see where or feel where-Not Likely because I felt up and down the wire and did not feel a knick. 2. I somehow damaged the wires leading out to the mat when I put them in the wall, so I will check by taking out one piece of border tile and see if I knicked it. Likely, but probably not. 3. The other end of the floor where I cut off the mat, I did not insulate the ends that were cut off well enough and so I need to rip up part of the floor and insulate the ends. Most likely, but unknown if that could be the problem because it is farthest away from the sink on the other end of the room. Can someone who knows electricity tell me if the other end of the heated floor mat about 7-8 feet away, covered in mastic and stone tile could possibly be shocking me (very mildly) through the wall and the copper piping that there are no wires touching the copper piping, that far away? (It's the opposite wall too.) So, not even the same wall that the copper water pipes are in?