GFCI protection for electric radiant floor heat

Status
Not open for further replies.

unytko

Member
Location
NYC
If wall thermostat controling floor heating wire has built in GFCI protection is GFCI breaker still required?
 

Sierrasparky

Senior Member
Location
USA
Occupation
Electrician ,contractor
nope as long as the gfci is protecting the load side wires. I have seen relay systems that were not GFCI protected.
 

hurk27

Senior Member
If you put a GFCI breaker on the same circuit as a GFCI Tstat it will nuissance trip...unless it's a GFPE (30ma) breaker.

I shouldn't, the only problem of daisy chaining GFCI's is troubleshooting, you never know which will trip first or even both, I have had many calls because an outside receptacle was dead only to find it was also fed from a garage receptacle that was already GFCI protected, the home owner reset the outside GFCI but didn't know that the garage GFCI had also tripped.

This problem also happens with breakers if selective coordination hasn't been done.
 

Warmsmeallup

Member
Location
Upstate, NY
I shouldn't, the only problem of daisy chaining GFCI's is troubleshooting, you never know which will trip first or even both, I have had many calls because an outside receptacle was dead only to find it was also fed from a garage receptacle that was already GFCI protected, the home owner reset the outside GFCI but didn't know that the garage GFCI had also tripped.

With two GFCI's, the resistant load of the element will cause one of the GFCI's to trip...sometimes! Electric floor warming systems should always have their own circuit. All manufacturers of electric radiant specify it. If you don't install a separate circuit, it can void their warranty. (don't shoot the messenger!)
 

kwired

Electron manager
Location
NE Nebraska
With two GFCI's, the resistant load of the element will cause one of the GFCI's to trip...sometimes!

Unless there actually is a ground fault condition -- why? GFCI simply measures current in on one conductor and current out on other. If they are same it holds, if they are different it trips. If load is connected properly and has no leakage someplace then GFCI sees balanced (in and out) current.

It is very possible the GFCI that is part of the heating system is only the 30mA equipment protective type and not class A. This will result in the class A breaker being subject to trip without the unit device tripping.

I don't think there is a requirement in NEC for GFCI protection on these heating systems - it is a manufacturer reccomendation / or even listing requirement.
 

kwired

Electron manager
Location
NE Nebraska
See 424.44(G)

Good find - I opened my mouth without even looking. I will point out that according to that section GFCI is only required for floors of bathrooms and in hydromassage bathtub locations. Although not a requirement in other areas it is not prohibited and may be a good idea - at least at the equipment protection level.
 

Eagle126

Member
220 volt wall heater in residential bathroom

220 volt wall heater in residential bathroom

Does a 220 volt wall heater in a home need gfci protection?
 

hurk27

Senior Member
Good find - I opened my mouth without even looking. I will point out that according to that section GFCI is only required for floors of bathrooms and in hydromassage bathtub locations. Although not a requirement in other areas it is not prohibited and may be a good idea - at least at the equipment protection level.

I have never seen one of these floor heating systems that didn't require GFCI protection in their listed instructions, even their controls include it, so I would say it would be a 110.3 violation to not install it, also since the heating cable has a EGC shield enclosing the element, a GFCI would provide a safe way to shut the circuit down in any event of a failure with the heating element or damage by a nail. so even if a GFCI wasn't required I would always want it on one if it was my house.
 

Warmsmeallup

Member
Location
Upstate, NY
Well, GFCI would not be the correct term for it. GFCI breaks at around 5-6ma. Line voltage floor warming and exterior gutter mealt systems require GFEP (or GFPE) breakers which break at 30ma, as mentioned earlier in this thread. So, if you use GFCI at the main, you would need to use a GFEP at the tstat with line voltage floor warming elements or one of them will nusisance trip.
 

kwired

Electron manager
Location
NE Nebraska
Well, GFCI would not be the correct term for it. GFCI breaks at around 5-6ma. Line voltage floor warming and exterior gutter mealt systems require GFEP (or GFPE) breakers which break at 30ma, as mentioned earlier in this thread. So, if you use GFCI at the main, you would need to use a GFEP at the tstat with line voltage floor warming elements or one of them will nusisance trip.

The previously mentioned 424.44(G) requires GFCI protection for personnel. That is the 4-6mA variety GFCI.

If you did have a situation where you have both 4-6 and 30 mA on same circuit they will not interfere with each other. The 4-6 device will be the one that trips every time there is a 4-6 or higher ground fault but the 30mA device will only trip if the fault is above 30mA.
 
Status
Not open for further replies.
Top