Two GFI’s for a 220volt install?
Hey all…..
I installed a warm floor (wwww.warmtiles.com) in my bathroom floor. Because of the size of it I utilized a 220volt cable system and thermostat.
Never thought of the the GFI issue, but now realize it needs a GFI circuit breaker at the source. Question is this…. can I buy two 110 volt GFIs, one for each leg of the 220, or do I have to buy a dedicated 220volt GFI, which is about $135 compared to $25 or so for each 110 GFI?
Replies
dedicated....
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What amperage? 60 amp hot tub ones are about $85. Got the whole kit with recpt for service and gfci in wx proof box for $85 at Lowes. Where are you getting 120v for $25? I ended up paying $42 for GE 15A and 20A.
It is less than 15 amps. In fact, I think it is around 4 amps.Wallyo & USangiel........I looked at that website Wallyo and checked out that control. I have a similar control for my Warm Tiles which also states that it has an internal GFI. However, there is an asterisk by that statement so if you read the fine print it says that it requires a GFI protected circuit according to the National Electric Code. I will have to call Warm Tiles tomorrow and ask them what is up.
Also, the cables run into my walk-in shower. There is an area about 4 feet deep and 2.5 feet wide were we will stand to dry off that is heated. The cables were embeded per the instructions (mortar bed with cables in that, then the Kerdi waterproofing membrane, then the floor tiles on top of that, plus the epoxy grout), but I would feel better maybe if it was connected to a GFI circuit.
Edited 6/15/2008 8:12 am ET by jurassicjet
There is a special control just for this type of flooring with a built in GFCI. About $175. Check Homedepot online or http://www.warmlyyours.com
A 220volt GFCI is a one piece unit and priced high.
Why does it need a GFI is my question? I have never seen an electric heater of any type in a bath that needs a GFI. Not saying it doesn't just asking the question.
Wallyo
The short version is 'because the instructions say so.' A 240v circuit needs the expensive two pole GFI breaker. Single pole ones won't work. Installing floor heating mats is a delicate business. The instructions call for megger testing of the insulation ... and documentation of the tests .... at numerous times during the installation. The entire reason for these tests is to discover damage to the insulation as soon as possible - and to be able to assign the blame. More to the point ... with no other electric heat do you actually walk on it with wet feet. That heater in the wall can be a real shock factory - and you might never get zapped. Do you want to take the same chance as you step out of the shower? If our OP is not doing the required megger tests .... well, adios any guarantee, and it's his loss.
In the OP's case he is running it into what sounds like a drier but still wet portion of a shower.
That I understand.If just under a bath floor is a GFI still required? Again I am not doubting it just surprised, I have never installed one but have seen them installed on various home show too numerous too mention, and never heard talk of a GFI being used. I have heard how to test during installation, the alarms etc from the sound of it I would not install a mat withou, testing the system may not work as a result. So are you saying if you test you don't need a GfI?Wallyo
Under-tile heating mats are popping up like mushrooms after a rain ... I can't pretend to have read EVERY vendors' instructions. Yet, the ones I've seen all specify GFI protection. Bathroom floors get wet - that's just reality. Even the parts outside of the shower pan. because of the potential harm to a person standing on a charged floor, then touching a well-grounded bit of plumbing, I suspect the folks at UL are behind the GFI requirement. Also, the required megger testing suggests it's pretty easy to damage the mat during installation. You really want some protection. Consider the GFI to be a critical part of even the best mat install. Now, it's possible that the GFI protection was built into the controller / switch. I have noticed some mats insist you use only the supplied controller. Indeed, every mat maker I've encountered will sell only custom mat packages ... rather than, say, selling just the mat by the square foot. I don't understand the 'alarms' you refer to. A 'megger' is a particular - and expensive - piece of test equipment. While every sparky should have one, few have even seen one these days. There is no substitute for megger testing when you're checking insulation. There are several times during the installation when you test with the megger - and you keep a log of the results. Starting when you first take it out of the box, you test again when you put it down ... and again when you lay the mortar bed, and again when you set the tile, and again just before powering it up.
I have never seen the merger test done just, I guess a basic continuity test is what I have seen. Like the old ones used for auto applications, the lead battery and screwdriver type device. Except the one I am talking of has a 9 volt battery, attaches to the two leads during install, should the element get broken an alarm sounds.So your points are well taken for the doit your selfer electrician. There may be extra cost to add in should the controller not have a GFI built in. One should think about this in a 110 vs 240 application, and comparing system brands. Matt + controLler + GFI =$$$VSMatt +controller w built in GFI =$$$Plus the systems above in 110 vs 240.Thanks for the education and enlightenment. IF YOUR A DAD HAPPY FATHERS DAY!Wallyo
Thank you for your kind thoughts ... A megger works on a principle similar to a continuity tester. Think "continuity tester on steroids." That is, it is able to measure extremely small changes to the voltage that it applies to the wires. The tiniest loss indicates a flaw in the insulation. Also, unlike a continuity tester, a megger uses a much higher voltage - one that is high enough to hurt you if you're not careful. Whether or not you have a GFI, you should test the mat at the times I mentioned. You have an interest in finding a faulty mat before the tile is all set in place. Wire that 'meggers' well won't let anything out to shock you. A GFI shuts the power off after the leakage becomes enough to shock you. The two work together. Since insulation does degrade over time, this is an important protection.
Thanks for the heads up on the circuit breaker issue. It looks like I will have to utilize a dedicated 220 volt GFI circuit breaker.
As far as megger testing, I did not do that. Never heard of it actually but then I am not an electrician either. I did do an ohm test after the cable was placed and also again after the floor leveler was put down. As far as assigning blame, I am the one who did the install so the blame would be mine. I have plenty of blame to go around for the rest of the contractors though....like improper window install, but I digress.
Stumbled on this ebay:
http://cgi.ebay.com/SQUARE-D-HOMELINE-50-A-HOM250GFIC-CIRCUIT-BREAKER-NEW_W0QQitemZ320261581744QQihZ011QQcategoryZ104232QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262
Hey Rasconc,Thanks for the link to that.
That is a 50 amp circuit breaker. The draw on my 220 volt system is 4 amps. I am thinking that 15 amp circuit breaker would be the biggest system that I would like to install. Heck of a deal on those 50 amp breakers though. I am guessing that they are for a hot tub install, but not sure.
The control that came with my under floor heating mat had GFCI built in. It also had a thermostat sensor that got bedded into the thinset to monitor the temperature at the floor.
It looks like this .
A warm floor in the winter is the cat's meow; only thing better is a towel warmer. In my case, both are controlled by the aforementioned AUBE thermostats. .
Yep, mine is basically the same thing with a temp sensor in the floor and a built in GFI. The instructions and company is still calling for a GFI at the source (panel) so it looks like about $132 (ouch) for a 220 GFI 15 amp CB.
I checked with my sparky today since I saw him anyway. He was not sure but needed to look it up ( I told him I had a good code trivia question for him when I talked to him on the phone). The way the 2008 code reads is in bathrooms and wirlpool areas in floor heat mats must be GFCI protected. But he also said that if the GCFI is in the timer you do not need one at the panel. You can only put one in regardless, it would be bad practice to put two in.Best think is call the inspector if you did not pull a permit, just ask over the phone you do not even need to give your name.Wallyo