FCU Cable Size ?

[kevmcdo9]

Was changing a socket today and noticed that the cable runnig to the fcu which supplies my combi boiler was 1.5mm2 is this safe ?? the cable run for about 1.5 meters . any help appreciated

 

[OwainDIYer]

It's difficult to say whether it's completely compliant, in that protection against overload is provided by the downstream FCU, which for a boiler should be 3A, and protection against short circuit *hopefully* is still provided by the 32A circuit MCB.

However that can only be proved by measurement and calculation.

If the wiring still has rewireable fuses, there's rather less room for error on cable sizes.

For 1.5 metres if it's reasonably accessible I would redo the job properly with 2.5mm.

 

[ericmark]

It is permitted it says:-
433.2.2 The device protecting a conductor against overload may be installed along the run of that conductor if the part of the run between the point where a change occurs (in cross-sectional area, method of installation, type of cable or conductor. or in environmental conditions) and the position of the protective device has neither branch circuits nor outlets for connection of current-using equipment and fulfils at least one of the following conditions:
(i) It is protected against fault current in accordance with the requirements stated in Section 434
(ii) Its length does not exceed 3 m, it is installed in such a manner as to reduce the risk of fault to a minimum, and it is installed in such a manner as to reduce to a minimum the risk of fire or danger to persons (see also
Regulation 434.2.1).

 

[ricicle]

Has nobody bothered to read table 4D5 ?

 

[Spark123]

What size and type of fuse protects the socket circuit?

 

[kevmcdo9]

What size and type of fuse protects the socket circuit?

Its protected by a 30amp Wylex circuit breaker.

 

[sparkwright]

So you have a 1.5 mm cable running off a socket that is protected by a 32 amp mcb?

I would recommend changing the cable for 2.5 mm, or protect the 1.5 with a 13 amp fused spur unit?

Out of interest, how many other cables are at this socket supplying the 1.5?

 

[kevmcdo9]

So you have a 1.5 mm cable running off a socket that is protected by a 32 amp mcb?

I would recommend changing the cable for 2.5 mm, or protect the 1.5 with a 13 amp fused spur unit?

Out of interest, how many other cables are at this socket supplying the 1.5?

Yeah thats correct it has 3 in each terminal.

 

[ricicle]

I would recommend changing the cable for 2.5 mm, or protect the 1.5 with a 13 amp fused spur unit?

Why. As the circuit stands at the moment the cable is protected by the FCU at the load end. Does anyone read the regulations thoroughly ?

 

[sparkwright]

I would recommend changing the cable for 2.5 mm, or protect the 1.5 with a 13 amp fused spur unit?

Why. As the circuit stands at the moment the cable is protected by the FCU at the load end. Does anyone read the regulations thoroughly ?

As I understood the post the cable FEEDING the boiler switched fused spur is fed in 1.5 mm. The 1.5 mm cable is spurred from a 30 amp ring circuit. So the 1.5 mm cable isn't properly protected in my opinion.

Advance appologies if I have misinterpreted the op.

 

[kevmcdo9]

I would recommend changing the cable for 2.5 mm, or protect the 1.5 with a 13 amp fused spur unit?

Why. As the circuit stands at the moment the cable is protected by the FCU at the load end. Does anyone read the regulations thoroughly ?

As I understood the post the cable FEEDING the boiler switched fused spur is fed in 1.5 mm. The 1.5 mm cable is spurred from a 30 amp ring circuit. So the 1.5 mm cable isn't properly protected in my opinion.

Advance appologies if I have misinterpreted the op.

Just to clear it up the cable from the socket to the fcu is 1.5mm2, its protected by a 3amp fuse in the fcu.

 

[1john]

So we have a 1.5mm cable with a 3amp load on it, whats the problem?