Bathroom UFH earth mesh

[marcuswareham]

Whist looking up something unrelated in section 701, I noticed reg 701.753

Stating that underfloor heating wire in a bathroom must have an earthed sheath or metallic earth grid etc etc & that electrical separation shall not be used

It got me thinking, the underfloor heating wire I used in my conservatory has no earth and is double insulated (different version in the bathroom).

Although I don't have an issue I am wondering if someone was to find underfloor heating in a house whilst doing a repair or an EICR or whatever and It was in a bathroom / shower room , and there was no earth conductor present or evidence to suggest it has an earth mesh, sheath or enclosure. What would you do as I can imagine if you tell the client you need to remove the bathroom floor I doubt that would go down well, and as the reg states using an isolation transformer is also not allowed?

 

[Wilko]

EICR or whatever and It was in a bathroom / shower room , and there was no earth conductor present or evidence to suggest it has an earth mesh, sheath or enclosure. What would you do

Hi, I’m a simple person and so if I’m doing a Report, I report what I find .

 

[westward10]

Double insulation isn't normally considered as a means of protection in a dwelling so this is an interesting question. Why don't you email the manufacturer.

 

[marcuswareham]

Hi, I’m a simple person and so if I’m doing a Report, I report what I find .

Fair enough, I should have said if you were asked to fix and issues

 

[loz2754]

I'm not sure how you would go about ascertaining whether a mesh has been installed or not. You can only inspect what you can see.

 

[Wilko]

If there was no earth on the ufh cable and no mesh and it’s within Zone 2 then the only fix I can think of would be to decommission it, sorry. Hopefully someone has another thought …

 

[marcuswareham]

If there was no earth on the ufh cable and no mesh and it’s within Zone 2 then the only fix I can think of would be to decommission it, sorry. Hopefully someone has another thought …

Dont be sorry, I dont have this problem my bathroom UFH has earth

was just question i wall mulling over and trying to work out if there could be any other solution, as you say probably not

 

[LastManOnline]

Double insulation isn't normally considered as a means of protection in a dwelling so this is an interesting question. Why don't you email the manufacturer.

I find that "double insulated" accessories are becoming increasingly problematic from a testing(EICR) point of view. It's sometimes difficult to know if you have discovered an unearthed appliance or simply found a "double insulated" appliance. "Double insulated" appliances can look just as "metallic" as their class 1 cousins. Just today I brought home a metallic "double insulated" downlighter removed from an install to add to my growing collection of "baffling" "double insulated" accessories.

 

[LastManOnline]

If there was no earth on the ufh cable and no mesh and it’s within Zone 2 then the only fix I can think of would be to decommission it, sorry. Hopefully someone has another thought …

Does zone 2 extend to beneath the floor?

 

[loz2754]

Does zone 2 extend to beneath the floor?

No it doesn't.
The zone is irrelevant for the purpose of the regulation requiring an earth grid.

 

[Wilko]

Does zone 2 extend to beneath the floor?

Hi - no, but my interpretation of Reg 701.32.1 (last paragraph) is the heating mat being part of the floor means the zone requirements apply. Just my opinion and I am extending beyond what is written, as the reg only states this for walls and ceilings.
If we weren’t in a bathroom then 753.411.3.2 says Class 2 mats may not require the extra metal grid / mesh.