Fusing down for lighting.....

[spud1]

Hi,

Just been and looked at a job done recently by a colleague.
SWA dedicated 16A supply from a garage consumer unit to a external socket outlet and bulkhead light with external switch on an adjacent patio.
He hasnt provided any fusing down for the light and external switch.. (i.e. via an external switched fused spur, as I would have probably done)
He has posed the argument that because he has wired the switch and light in 2.5mm cable that the 16A circuit OCPD is sufficient, but I am concerned that the bulkhead light fitting and external switch have current ratings <16Amp.
He says its no different from a 13A socket outlet being protected by a 32Amp MCB on a ring final circuit, which I can't disagree with him on.

Can anyone provide some clarity on this for me please?

 

[pc1966]

A 13A socket on 32A MCB is totally different - it has the <= 13A fuse for OCPD on the switch and plug contacts!

Given that most light switches are 10A max and many light fitting are designed for lower OCPD I would not be terribly happy. However, with it all in 2.5mm cable at least the 16A breaker is ample protection for the wiring both fault and overload.

 

[Julie.]

A 13A socket on 32A MCB is totally different - it has the <= 13A fuse for OCPD on the switch and plug contacts!

Given that most light switches are 10A max and many light fitting are designed for lower OCPD I would not be terribly happy. However, with it all in 2.5mm cable at least the 16A breaker is ample protection for the wiring both fault and overload.

Agree.

But there isn't technically anything wrong with it - it is a "fixed" load - you would struggle to fit a lamp in the holder that exceeded 10A therefore from an overload perspective no problem, and providing the Zs is low enough fault protection is there.

The only issue is if the luminaire' instructions state 10A max ocpd or similar

 

[spud1]

Agree.

But there isn't technically anything wrong with it - it is a "fixed" load - you would struggle to fit a lamp in the holder that exceeded 10A therefore from an overload perspective no problem, and providing the Zs is low enough fault protection is there.

The only issue is if the luminaire' instructions state 10A max ocpd or similar

Thankyou very much Guys and Girls.
Have just looked into it, the switch is rated at 20A anyway and the light fitting is just a GLS lampholder in a polycarb bulkhead (no internal wiring or gear) so have referred to reg 559.5.1.204 for justification
So Ive let him off on this one but politely asked that, in the interests of good practice, he get into the habit of fusing down lighting in any future similar circumstance!

 

[telectrix]

always a good idea to fit a 5A D/P FCU for outside lights. then in the event of a fault the light/s can be isolated and customer still has use of sockets.