Heated bathroom tile slight shock problem

Status
Not open for further replies.

renosteinke

Senior Member
Location
NE Arkansas
I can't access all my resources - I'm too busy, in Arkansas, making tornados to export to my Southern neighbors - but pause to think about it for a moment.

Here you have a fine wire mesh, wrapped in rubber. During installation, it will be walked on. There might be sharp rubble on the floor. The edges of trowels can get razor sharp with use. Tiles themselves have some pretty good edges, and all the weight of the tile behind them when they fall. I see plenty of opportunity for the insulation to get damaged.

Now ... how will you inspect for damage? All a continuity tester (or ohm meter) will tell you is if the wire is at least somewhat complete from one end to the other. You can remove ALL the insulation, and the meter won't see the difference.

A megger, on the other hand, can best be described as a tool that 'fills a wire with pressurised electricity' ... and then lets you know if even a little bit is leaking out. With something like a heat mat, you don't test between the hot and the neutral - they're supposed to be connected - you test between each of them and the ground. There better not be any electricity getting into that ground . If there is no ground wire, you test between each lead and the mat itself. All the electricity is supposed to stay in the wires.

Now ... do you want to do this only at the start of the job? At the end? Or, at each step along the way? I'd say it's in your interest to stop work as soon as a fault develops. I really like the 'alarm' fulthrotl described. because no one is likely to volunteer to pay to replace the floor, or trash the production schedule.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
I cant seem to find the word megger in the first link here

http://www.nuheat.com/customer-care/manuals.html

Acquire a digital ohm / multimeter with alligator clip attachments or equivalent testing
device.

Actually, since they specify a DVOM, I wouldn't use a megohmmeter for the required testing.

During troubleshooting I would also hold off unless a DVOM showed infinity and I was certain that putting 500 volts into the mats wouldn't damage them.
 

CAsparky

Member
Location
San Diego
Thanks for the replies. Still trying to find what brand was installed. It is a new install. Not sure if the problem occurred right out of the gates. There is a dead space behind a cabinet where all the wires come up. They are thhn which i was told are the wires that come from the mats. They are spliced to a low voltage cable which goes to the attic. It splits off to the thermostat and comes back to the transformer. The transformer is the one that came with the mats and it plugs into a properly grounded outlet.

When i go back I guess Ill disconnect all the thhn wires and do a continuity check to see if I can find a short. If so then the mat will probably get eliminated as I doubt the owner wants to tear up the new tiles.
 

K8MHZ

Senior Member
Location
Michigan. It's a beautiful peninsula, I've looked
Occupation
Electrician
Thanks for the replies. Still trying to find what brand was installed. It is a new install. Not sure if the problem occurred right out of the gates. There is a dead space behind a cabinet where all the wires come up. They are thhn which i was told are the wires that come from the mats. They are spliced to a low voltage cable which goes to the attic. It splits off to the thermostat and comes back to the transformer. The transformer is the one that came with the mats and it plugs into a properly grounded outlet.

When i go back I guess Ill disconnect all the thhn wires and do a continuity check to see if I can find a short. If so then the mat will probably get eliminated as I doubt the owner wants to tear up the new tiles.

The Nuheat link provided requires a GFCI

It is mandatory to install a Class ?A? GFCI or GFCI circuit breaker with each Nuheat Mat Installation.
 

growler

Senior Member
Location
Atlanta,GA
A friend of mine has heated tile in his bathroom. When the heat is on and he turns on his faucet he gets a slight shock and he is barefooted.

It is a new install.


If it's a new install it should be under warranty so tell the homeowner to call the company that did the installation and tell them they have a problem.

As Gerald Ford said "the buck stops there" ( or something like that ). :roll:
 

hurk27

Senior Member
Thanks for the replies. Still trying to find what brand was installed. It is a new install. Not sure if the problem occurred right out of the gates. There is a dead space behind a cabinet where all the wires come up. They are thhn which i was told are the wires that come from the mats. They are spliced to a low voltage cable which goes to the attic. It splits off to the thermostat and comes back to the transformer. The transformer is the one that came with the mats and it plugs into a properly grounded outlet.

When i go back I guess Ill disconnect all the thhn wires and do a continuity check to see if I can find a short. If so then the mat will probably get eliminated as I doubt the owner wants to tear up the new tiles.

I'm interested in the brand also, I have never seen a low voltage mat system for inside floors, (not that they don't make them) the only ones I have seen was for drives and patios, the current at lets say @ 30 volts would be quite high, and this in itself would be a danger, I just cant see low voltage being used. outside I can see it.
 

Riograndeelectric

Senior Member
Thanks for the replies. Still trying to find what brand was installed. It is a new install. Not sure if the problem occurred right out of the gates. There is a dead space behind a cabinet where all the wires come up. They are thhn which i was told are the wires that come from the mats. They are spliced to a low voltage cable which goes to the attic. It splits off to the thermostat and comes back to the transformer. The transformer is the one that came with the mats and it plugs into a properly grounded outlet.

When i go back I guess Ill disconnect all the thhn wires and do a continuity check to see if I can find a short. If so then the mat will probably get eliminated as I doubt the owner wants to tear up the new tiles.



If this is a new installation I would question why the customer did not call the installer to check matt out?

I have never seen factory conductors that were THHN conductors. all of the mats I have installed have the factory conductors as a shielded conductors and require that the conductors from the heat mat be installed in a conduit system.

if it is low voltage I doubt that it is listed as a Class 2 power and wires would need installed in a conduit system Flex , smurf tube etc.



low voltage mats would require a lot of current.Ii have not heard or saw low voltage Matt's or heating mats that plug in.

can you get a hold of the instructions that came with the mat?

sounds to me like a Jerry rig Job

lets us know what you find out
 

Steviechia2

Senior Member
Location
Massachusetts
I'm interested in the brand also, I have never seen a low voltage mat system for inside floors, (not that they don't make them) the only ones I have seen was for drives and patios, the current at lets say @ 30 volts would be quite high, and this in itself would be a danger, I just cant see low voltage being used. outside I can see it.

Lo-voltage + high wattage, that sounds warm already :grin:
 

Fulthrotl

~Autocorrect is My Worst Enema.~
I can't access all my resources - I'm too busy, in Arkansas, making tornados to export to my Southern neighbors - but pause to think about it for a moment.

Here you have a fine wire mesh, wrapped in rubber. During installation, it will be walked on. There might be sharp rubble on the floor. The edges of trowels can get razor sharp with use. Tiles themselves have some pretty good edges, and all the weight of the tile behind them when they fall. I see plenty of opportunity for the insulation to get damaged.

Now ... how will you inspect for damage? All a continuity tester (or ohm meter) will tell you is if the wire is at least somewhat complete from one end to the other. You can remove ALL the insulation, and the meter won't see the difference.

A megger, on the other hand, can best be described as a tool that 'fills a wire with pressurised electricity' ... and then lets you know if even a little bit is leaking out. With something like a heat mat, you don't test between the hot and the neutral - they're supposed to be connected - you test between each of them and the ground. There better not be any electricity getting into that ground . If there is no ground wire, you test between each lead and the mat itself. All the electricity is supposed to stay in the wires.

Now ... do you want to do this only at the start of the job? At the end? Or, at each step along the way? I'd say it's in your interest to stop work as soon as a fault develops. I really like the 'alarm' fulthrotl described. because no one is likely to volunteer to pay to replace the floor, or trash the production schedule.

ok... here is the supervisor that should be kept continuously on the mat
until you trim out and power it up....

http://www.nuheat.com/products/accessories/matsense-pro.html

as for meggering the mats, the nuheat mats have a shield around the
power leads, and you megger from the power leads to the shield.

i use a fluke digital meggar, and megger them at twice the working
voltage... my meter can be set from 50v to 1000v, so 250 volts is
reasonable.

now, if we are gonna get anal about it, the mats need to have insulation
rated at 600 volts... and from my days in capacitor manufacturing, a
very common hipot voltage was 150% of the rated voltage.... so you
should be able to hipot 600 volt insulation at 900 volts without any issues.

the whole advantage of insulation resistance, hipot, or megger tests is
that it loads the insulation, and gives a real world idea of where the
insulation integrity is at.

simple resistance from a meter leaves too much to chance, imho.
i megger the mats before taking them outta the box, after placing
them, after the grout is poured over them, and after the tile is set.
then i megger them right before i put the power to them.

that's my nickels worth.


randy
 
Status
Not open for further replies.
Top