Hi,new to the forum after advise and willing to learn Thanks

[Eazy 26]

Hi
I'm after some advise on electric underfloor heating?

I've recently taken over a job were the previous electrician (kitchen fitter) has left the job half done and left them with an unfinished job mainly all 2nd fix

He's laid 2x 20m matts to cover a 40sqm room and he's put 1 prob and Both tails from each matt to a 35mm box with a supply from a dedicated circuit which was isolated by a 20amp double pole switch the two matts will be controlled by one thermostat rated at 16amps. from what I have found out through the customer is that the Matt rating was 200wpm so by my calculation
40x200 = 8kw /230 = 34.78amps.

So 34.78 amps into 16amp thermostat?
What's my solutions?

I've had a quick read up about contactors ,relays and snubs to be honest I have never used any of these so not sure on were and how to wire them into the circuit.

This install is completely plastered/decorated so re-wiring or major changes to the circuit can't be done unless local to existing wiring

After any helpful advise

Cheers

 

[telectrix]

what lunatic specified electric underfloor heating for a room that size. madness. something close to £100 / week in leccy.

 

[SparkyChick]

How big is the supply cable and associated MCB?

 

[westward10]

Use the stat to switch a contactor, this may have been the original intention.

 

[Eazy 26]

How big is the supply cable and associated MCB?

There is a 4mm at the 20amp point with a 2.5mm upto the stat the cable hasn't been installed in the ccu yet

 

[Eazy 26]

what lunatic specified electric underfloor heating for a room that size. madness. something close to £100 / week in leccy.

They were sold it as part of the kitchen install I had a rough measure up and you could of got away with 0ne 20m Matt after you minus all the fixtures and fittings the Matt goes under all the units

 

[Eazy 26]

Use the stat to switch a contactor, this may have been the original intention.

What type of contactor would be needed?
And can you get small contactors that would fit inside a 35mm box?

In my mind I would have a feed from the stat to a contactor and the cold tails to the contactor aswell?

 

[westward10]

A contactor will have to go in a surface enclosure.

 

[Michael4321.]

You forget about the (cos the power factor after all calculation when refer to also Resistance.

 

[soulman]

Hi Screwfix, do A BG 40A contactor for £20.00.