Floor warming cable

[goldstar]

If anyone has had some experience with installing floor warming cable I'd appreciate some input or opinions.

I'm currently installing this cable in a new residence in 4 rooms (sun room, kitchen, main foyer and master bath). Each cable is embedded in a layer of thin-set and then tiled over and is powered by a dedicated 20 amp, 240 volt circuit. The manufacturer (Delta-therm) suggests that anywhere there may be standing water or may come in contact with water pipes (i.e a bathroom) a GFI breaker be used.

Using a GFI breaker for the bathroom makes sense to me but should I be using GFI breakers for the other rooms ? Is there a code guideline for this ? Thanks in advance.

 

[daveselectric]

Re: Floor warming cable

Follow the manifacturers specs and you will be ok.

 

[rrrusty]

Re: Floor warming cable

The GC that I work for had this type of stuff installed on one job and after hook up only one of the two loops worked (one of his laborers installed it) and so last I heard he just kind of forgot about it; Installation needs to be very careful

 

[canadian]

Re: Floor warming cable

Ive used a product called'easy heat warm tiles'.You can do a search on the web. The new standard thermostat kits they sell are programmable and come with built in GFCI protection.Anyways that being said..I dont see any need for GFCI protection in any of the other three rooms you mentioned.Those breakers are too expensive to go above and beyond in my opinion.P.S...I have it in my baathroom and it is now my favorite room in the house

 

[al hildenbrand]

Re: Floor warming cable

Goldstar,

See 424.44 & .45, and as to the GFI question, specifically as to where required, 424.44(G). The NEC Handbook (in case a copy is not readily available) adds this text after 424.44(G)

Section 424.44(G) requires the use of GFCI protection where cables are installed in concrete or poured masonry floors, thereby reducing shock hazards to persons with bare feet in these areas. For the 2002 Code, the reference to conductive floor coverings was removed to clarify the requirement for GFCI protection in all of the areas identified in 424.44(G), regardless of the type of floor covering over the concrete or poured masonry.

 

[al hildenbrand]

Re: Floor warming cable

Goldstar,

I forgot to add, in my experience, timing and communication is everything.

Time the install of the cable for immediately before the tile guy lays the thinset. Absolutely close off the area until the thinset goes down. Take resistance and continuity measurements before and after thinset and record on a tag that is visible to the tileguy. Take resistance and continuity again when finishing the install, prior to energizing. . .there's no accounting for somebody needing to drill a hole in the floor after the floor is down.

 

[electricmanscott]

Re: Floor warming cable

Al, that is the first thing that I read but the installation in question here does not mention what type of material it is being installed in other that thin set mortar, which I don't think qualifies as "concrete or pured masonary". I would probably refer to the manufacturers info and install gfci. I too installed some of this stuff in my bathroom and it is awesome!

 

[al hildenbrand]

Re: Floor warming cable

Scott,

That's an interesting distinction. I've not examined the printed literature on thinset before. I can't search for it at the moment. . .does anyone have a reference?

It looks like a duck and quacks like a duck, to me.

 

[goldstar]

Re: Floor warming cable

Thank you all for your replies. Section 424.44(G) states that GFI protection is required for bathrooms, hydro-tub and hot tub locations only. There is no mention of a requirement for other locations.

Section 424.44(D) states that a spacing be maintained between the cable and metal embedded in the floor. The cable supplied with this product consists of # 12 wire in some type of rubber insulation wrapped by a shielded wire and enclosed in a rubber jacket. The shielded wire is bonded to ground in the thermostat JB. I would hope that if the wire somehow gets pinched or cut by the wire mesh that it would short to ground before the power conductor could energize the wire mesh.

I can't tell you much about the thin-set with respect to it's characteristics. But I can tell you that there is about 1/2" of thin-set encasing the cable and wire mesh and another 1/2" of thin-set over that to bond the tile.

Just something else to consider for anyone installing this for the first time : Section 424.44(E) states that conductors leaving the floor are to be protected by EMT,IMC, NMC or other approved means. I had installed a piece of 3/4" Carlon flexible PVC for the cold leads of the warming cable. There was enough room to get those leads into the conduit up to the point where they spliced onto the warming cable. However, I did not make provisions for the thermostat cable and had to snake it up into the JB. The manufacturer's drawings showed the thermostat enclosed in a piece of 1/2" EMT which I could not do after the fact so I ended up using a small piece of 3/8" copper tubing and it seemed to work out OK.

Thanks again.
Phil,
Gold Star Electric

[ June 01, 2003, 07:49 AM: Message edited by: goldstar ]