Underfloor Heating

[revilotah]

Hi im new to the forum, a DIY enthusiast. I have underfloor heating, originally made up of 20meters of cable, running 240 V at 320 W 160 ohms. Now i want to half this same cable to 10m, however this would lead to a reduction of resistance by half, effectively doubling the power going through the cable, leading to it over heating. How about running the circuit on a 110V transformer i ask myself. So i try it and the cable does not get hot at all. Any Ideas?

Many Thanks.

 

[Dan]

Welcome to Electricians Forum | Electrical Advice Forum | An electrical forum for electricians in the UK!

Welcome to electriciansforums.net revilotah. Thanks for introducing yourself.

 

[Hawk81]

Hi im new to the forum, a DIY enthusiast. I have underfloor heating, originally made up of 20meters of cable, running 240 V at 320 W 160 ohms. Now i want to half this same cable to 10m, however this would lead to a reduction of resistance by half, effectively doubling the power going through the cable, leading to it over heating. How about running the circuit on a 110V transformer i ask myself. So i try it and the cable does not get hot at all. Any Ideas?

Many Thanks.

surely if it is designed to work at 230v it will not work at 110v. If you are halfing the length of it and reducing the resistance by half then you will reduce the watts by half too?

 

[revilotah]

surely if it is designed to work at 230v it will not work at 110v. If you are halfing the length of it and reducing the resistance by half then you will reduce the watts by half too?

I just ran a test at 110V with the thermostat cut out the circuit and the cable got warm but no where near the temp that is required, i guess the micro controller in the thermostat will not operate at the lower voltage.

What to do...

 

[UNG]

surely if it is designed to work at 230v it will not work at 110v. If you are halfing the length of it and reducing the resistance by half then you will reduce the watts by half too?

I don't think so reducing the resistance by half will double the watts

 

[UNG]

I just ran a test at 110V with the thermostat cut out the circuit and the cable got warm but no where near the temp that is required, i guess the micro controller in the thermostat will not operate at the lower voltage.

What to do...

At 110v with a resistance of 80 ohms your cable will only deliver 150 watts of heat

V² ÷ R = Watts

 

[revilotah]

Update: i reduced the length to 6.5 meters to reduce the resistance in an attempt to increase watts, this worked reasonably well, but of course i now have a shorter cable than is required. My 110V transformer has two outputs... maybe having two circuits is an option?

 

[Sintra]

Hi & welcome.

 

[acat]

Hi and welcome pleased you joined us


Chris

 

[Guest123]

Welcome along.

 

[davelerave]

Update: i reduced the length to 6.5 meters to reduce the resistance in an attempt to increase watts, this worked reasonably well, but of course i now have a shorter cable than is required. My 110V transformer has two outputs... maybe having two circuits is an option?

if you cut it in two each half requires 120v to deliver 320watts total

half the voltage -half the power for 10M( if the controls suit)

 

[kung]

Hello and welcome also.