underfloor heating

[drayton]

Hello, with regard to underfloor heating mats, the new regs 753.411.3.2 state, "in the case of heating units delivered without exposed conductive parts, a suitable conductive covering, for example a grid with a spacing of not more than 30mm shall be provided on site as an exsposed-conductive-part above the floor heating elements ". the unit I use has an earthed screen around the cables. Whats the purpose of the above, it wont provide any mechanical protection ?. can someone enlighten me, Cheers Drayton.

 

[Shakey]

Because this must be on its RCD, its ensuring that any breakdown of the live conductors gets picked up by the earth system (hence the screening or grid)

 

[drayton]

Yeh, Thats my point , the wire mat system has an earthed screen which if there is a breakdown on the live conductors, the RCD will trip, I dont get why there needs to be a separate exposed earth grid, or am I being thick.