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TPES

Simple quick question

Im going to put a new feed to a boiler, into a switched spur as it is now..

The cable being used at the moment is black rubber flex with a 3a fuse. (not sure if this was done right in past)

What size cable do i replace this with..?

Is 0.75 heat resistance flex Ok on a 3a fuse? or does it have to be bigger csa?
 
Normally a 5A switch fuse supplying a (modern) combi boiler. Heat res flex only really needed for Immersion Heater supply...most modern boilers are "cool touch", negating the need for a heat resistant cable.
hope this helps
Randyrat
 
Oops....forgot to answer the question.....
Depending on factors such as ambient temp etc which derate the supply cable, as a rough guide a 1mm cable will cope with 15.5 amps clipped direct...plenty!! Obviously if its a hundred yards long through insulation you need to perform the full calcs to determine current carrying capacity. If in doubt go large!!!!
 
Simple quick question

Im going to put a new feed to a boiler, into a switched spur as it is now..

The cable being used at the moment is black rubber flex with a 3a fuse. (not sure if this was done right in past)

What size cable do i replace this with..?

Is 0.75 heat resistance flex Ok on a 3a fuse? or does it have to be bigger csa?


hi there

small world a city and guilds design project has this in it !
i have run to the spur in 2.5mmm2 but from the spur to the combi is left to the designer

answer look at the manufactureres installation instructions


cheers
 
hey guys

what cable size/type would u use in a plug point for a boiler? I have a friend installing a boiler and shes asking for a plug point up in her loft? Wanted to know if i could help.

thanks..

nick
 
See the comments above. Size the cable(flex) in relation to demand info. Preferable to have heating supply on it's own radial to a SFS, appropriately fused, not off a RMF.
Regards.
 

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Combi boiler feed..?
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