C/Heating boiler fuse

[ugjointer]

Is a 16 amp fuse in the CU ok for a central heating boiler ,the boiler is wired up to this with 2.5 cable then a fcu with a 3 amp fuse into the boiler

 

[PrenticeBoyofDerry]

Providing the cable is not routed through thermal insulation.

 

[Steve]

its the 3 amp fuse thats protecting the boiler, this is fine.

 

[ericmark]

Sounds normal.

16A is to protect the 2.5mm cable not central heating unit.

3A in fused connection unit may protect boiler but this would depend on manufacture most include fuses inside the boiler but often the externals are protected by the 3A in fused connection unit. Pump etc.

Why do you ask.

 

[ugjointer]

Hi,Ihave been posting on this site regarding a CU unit and other associated things and noticed that the boiler was fed via a 16 amp fuse in the CU to a FCU witha 3 amp fuse and I just wondered if this was ok .It's been installed for 5 years now with no problems.

 

[Taylortwocities]

But its when you have problems that faulty wiring, wrong fuses, etc causes grief.

However, in your case, everything appears to be just fine.

 

[PrenticeBoyofDerry]

Your 2.5mm T+E should carry 27A safely, providing the cable is not route through thermal insulation(rockwool etc..) and/or grouped with other cables.
This can reduce the current carrying capacity of the cable due to heat.
If the cable is surrounded by thermal insulation it could reduce the capacity of the cable to half it's value ie 27/2=13.5A.
So if that was the case a 16A protective device could be dangerous as it exceeds the safe limit of 13.5A.