Found During I&T

[sparky1690]

i have just inspected a couple of buildings & found several problems.

10mm to 2.5mm with no inline fuse/mcb for a lighting cct.

4mm lighting cct protected by 32A Type C leadfing to the Zs falling outside the tabulated values but protected by RCD so gets away with it, not correct i know.

and several other things.

my question is which would be the easiest way for the client to rectify the fist issue, drop in fuse holder/MCB within the JB????

cheers.

 

[Sparky Ninja]

Install any necessary overload protective device where the cable size changes. There will already be a joint of some kind.

 

[sparky1690]

it goes into a JB then through a connector block.

the two i mentioned are what i would normally use BUT i wondered if there were any other alternatives as we are in the middle of the desert & cannot just pop down to CEF etc.

thanks.

 

[Sparky Ninja]

Fuse connection unit?

 

[sparky1690]

did think of that BUT was unsure if 10mm will fit as it loops to the next fitting.

 

[Sparky Ninja]

Where does 10mm become 2.5mm?

 

[Smugley]

The 10mm cable run may be to avoid voltage drop. So long as the circuit ocpd is selected according to the smallest conductor size I don't think this is necessarily a problem.

 

[Sparky Ninja]

433.2 I think covers this. I can't remember if it takes the OPCD into consideration though.

 

[Smugley]

What about 433.3.1 (i) - it's not exactly clear but it could be interpreted to mean that an ocpd for a smaller sized cable could be located on the supply side of the point at which the reduction in size occurs - ie at the CU. Or am I misreading this?

 

[IQ Electrical]

It is quite common to run a larger csa cable on large circuits, reducing the csa as the circuit progresses.

As has already been said (post 7), as long as the ocpd is selected with the lowest csa in mind then no further protection will be required

 

[Sparky Ninja]

433.2 refers to 433.3

You on the right lines, the OP needs to refer to the OPCD and consider it with the smallest conductor size.
Without knowing the current OPCD rating we are all just guessing.

 

[SirKit Breaker]

it goes into a JB then through a connector block.

the two i mentioned are what i would normally use BUT i wondered if there were any other alternatives as we are in the middle of the desert & cannot just pop down to CEF etc.

thanks.

Screwfix, order before 6pm, its in your hand tomorrow morning

 

[sparky1690]

the lighting cct's are being protected by C32 breakers so again not ideal.

 

[sparky1690]

Screwfix, order before 6pm, its in your hand tomorrow morning

somehow i doubt it Sir Kit