Under floor heating over 3kw

[westward10]

How come you are concerned with what the builder has done.

 

[HappyHippyDad]

How come you are concerned with what the builder has done.

Because he may not be as self assured as you are Westward. He probably has a working relationship with the builder and feels he has to tread lightly. Even though my builder is a friend there are still times when i think 'should I or should I not put my foot down on this point'. Having said that, this is one time I would definitely be putting my foot down.

 

[telectrix]

this is one time I would definitely be putting my foot down.

hopefully not too hard on the UFH mat.

 

[matthew stephenson]

1.5mm is the minimum for a power circuit. It's in the regs somehwere. 1.0mm is only acceptable for lighting circuits. Really should have it's own circuit also. Definately can't sign this off. What do you think the nic/napit inspector would say?

 

[Deleted account]

1.5mm is the minimum for a power circuit. It's in the regs somehwere. 1.0mm is only acceptable for lighting circuits. Really should have it's own circuit also. Definately can't sign this off. What do you think the nic/napit inspector would say?

What’s the definition of a power circuit?

surely all circuits are power circuits. I know I’m being pedantic, but I see nothing wrong with using 1 mm for a dedicated circuit that needs minimal power. Cheaper and better for environment.

i agree a spur from a socket circuit minimum is 1.5mm whether ring or radial as long as it is fused down as per regs and it’s what I do,

but in theory 1mm fused down spur from a ring or radial socket, I see nothing wrong with that.

 

[davesparks]

What’s the definition of a power circuit?

A circuit which is not a lighting circuit.

 

[Strima]

If you look at table 52.3 it also depends on the type and material used for the construction of the cable.

 

[lozarus]

Just an aside - I've only ever been involved with UFH once so am by no means expert, but I seem to remember the installation instructions for my example demanding IR tests to be done before the mats are fitted, once they're laid down and again after the floorcovering is installed to keep an eye on the condition of the mats throughout the installaton process. Certainly the one I used provided an area for these results to be noted and suggested it to be left by the CU (apologies can't remember the make). But with this in mind, i'd be concerned about an installation I hadn't been fully involved in

 

[Simon47]

Not just IR, resistance as well. Both should stay stable - you really need to detect faults before the floor goes down on top (especially tiles !)
IIRC, my mate's system came from Topps Tiles and the "one free repair" offer was conditional on having taken these measurements.