Fused spur rating for electric underfloor heating

[HenryCooper]

Builder installed 175w / sq metre in an area 6.7 x 3.5. What should the fused spur be rated at and should it have a contractor as well?

Am I correct in thinking it is drawing just over 17A therefore 13A fused spur is insufficient?

Thanks

 

[telectrix]

dedicated radial in 2.5mm on a 20A MCB. reference method C.

 

[telectrix]

and a roll of A4 paper to print off the lecy bill.

 

[DPG]

Is the spur (aka FCU) getting warm? I would probably switch it off until you have got to the bottom of things.

 

[Mike Johnson]

Is 6.7 x 3.5 the size of the mat or the room? its an odd size for a heating mat.

 

[buzzlightyear]

Builder installed 175w

Are you sure it's that cause 175/230 =0.7amps

 

[Mike Johnson]

Its 175W per sqm therefore you have to multiply the mat area by 175W thats why I asked it the area he quoted was the mat size or the size of the room.

 

[DPG]

6.7 x 3.5 = 23.45
23.45 x 175 = 4.1kW
4.1kW / 240 = approx 17A

Depending, as Mike said, whether this is mat size or room area.

OP, is the FCU ('spur') warm?

 

[telectrix]

OP, is the FCU ('spur') warm?

ask when he's taken the washing off of it.

 

[Dustydazzler]

A room this size would usually be 2 mats split across 2 Spurs / time clicks in my experience

 

[telectrix]

A room this size would usually be 2 mats split across 2 Spurs / time clicks in my experience

that's what i'd do. 2 mats, 2 stats.

 

[DPG]

that's what i'd do. 2 mats, 2 stats.

2 cats sat on 2 mats.

 

[telectrix]

2 cats shat on 2 mats.

stapled their tails together. Siamese cats. ?

 

[mattg4321]

The stats/programmers are nearly always rated at 16a, so if all on one it’s probably overloaded.

 

[Mike Johnson]

We have not heard back from the OP on the size of the mat or room, everything else is guess work, including how many cats are sat on the mat.

 

[buzzlightyear]

We have not heard back from the OP on the size of the mat or room, everything else is guess work, including how many cats are sat on the mat

maybe he is flying around on a magic carpet.lol ?

 

[DefyG]

Probably burnt his fingers checking if the S/FCU was hot and now cant type on the keyboard!

 

[HenryCooper]

and a roll of A4 paper to print off the lecy

6.7 x 3.5 = 23.45
23.45 x 175 = 4.1kW
4.1kW / 240 = approx 17A

Depending, as Mike said, whether this is mat size or room area.

OP, is the FCU ('spur') warm?

Thanks everyone, that was the room size....the problem was the fuse was blown and casing burnt...checked with the builder who installed it and the fused spur should have been 20A, but the matting is slightly under the size I quoted making it just under 16A which works for the Stat (but not clearly for the switch).

 

[DPG]

Thanks everyone, that was the room size....the problem was the fuse was blown and casing burnt...checked with the builder who installed it and the fused spur should have been 20A, but the meeting is slightly under the size I quoted making it just under 16A which works for the Stat (but not clearly for the switch).

I think you need to get your builder to pay for an electrician to put this right. And point out to him what he has done wrong - I bet he's done this in other properties as well.

 

[HenryCooper]

I think you need to get your builder to pay for an electrician to put this right. And point out to him what he has done wrong - I bet he's done this in other properties as well.

Thanks...that is what is now happening.....

 

[DPG]

Thanks...that is what is now happening.....

Great stuff. Keep us posted!

 

[Mike Johnson]

Is there any fixed furniture in the room now, if this furniture is on top of the mat this would cause localised heating and lead to a short circuit and blowing of the FCU, lots of variables that can not be ascertained from your posts.

What is the room used for?

 

[Taylortwocities]

checked with the builder who installed it and the fused spur should have been 20A,

There’s no such thing. 13A is the max fuse as protection from a spur. As above, needs a dedicated circuit. 20A MCB. And a 20A switch.

 

[Dustydazzler]

What’s the manufacturer rating on the stat / controls for the ufh

 

[Timbo]

A room this size would usually be 2 mats split across 2 Spurs / time clicks in my experience

Yeah, but this was installed by a builder.?