Is this a no no? I have located a ring main cable under the wetroom
floor and was planning on cabling in a switched FCU in zone 3 for my
UFH. Just stumbled across a posting which seemed to indicate that it's
against regs to even have ring main cable running under the bathroom
floor, is that correct? all these regs are soooooo confusing to
Also presuming this is ok could I run my towel rad from this too? The
towel rail will be in zone 3 also.
Any issues regarding regs with this lot?
Ideally, long-term substantial fixed loads don't run on rings, but on a
dedicated radial. How close your UFH comes to being 'substantial'
depends on its rating: if it's a small bathroom with say 1kW's worth of
UFH on an otherwise lightly-loaded upstairs ring, no real worries; if
it's 3kW of UFH (12A of the available 32A) on the only ring in the house
which also runs kitchen appliances, definitely *not*. Somewhere in
between is 'maybe' land. Like I say, optimal is a dedicated radial
running to the CU.
Towel rail is just fine from the ring - typical ratings are low hundreds
Rings routed under the floor of a bathroom is completely OK - although
running PVC cable buried directly in a concrete floor incorporating UFH
would be a Bad Thing and no mistake (for one thing, ambient temp for
such cable would be up around 50+ degrees, requiring substantial (60%?
figures not to hand!) derating).
HTH - Stefek
Based on the advice you gave me regarding my kitchen UFH sometime ago I
did some pre investigation work into this and the cable that I have
under the bathroon floor is a lightly loaded upstairs ring. Its a real
strange setup here being it 2 places converted into one and the ring
mains are not logical in the way they have been wired. Anyways doing
the math I think I'll be pretty safe here.
The main problem running *anything* under the bathroom floor is that of
accessibility. Don't put any junction boxes down there if you are
planning on installing flooring in the bathroom which cannot be easily
lifted for maintenance. Given that you are looking at UFH, your flooring
may well be tiles...
Ummm... and part P too.
Martin Angove: http://www.tridwr.demon.co.uk /
Two free issues: http://www.livtech.co.uk/ Living With Technology
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