Adding outside lights to MCB32, help

[andrewmccarthy79]

hey there. I don't really know much about electrics so i thought id try this out.

My Consumer Unit has a MCB 32 switch, which the cable(thick cooker cable) runs on the outside of my house into an empty box(which used to go to a shower).

My question is it possible to use this cable to connect 2 outside lights too, one with an PIR and the other one to come on with the first PIR??

i would be greatfull for any help

 

[Steve]

It would be easier / better if you could remove that cable completely, replace the MCB with a 6 amp one, and use 1.0mm hi-tuff cable to the above mentioned appliances from the start. Standard household twin and earth cable is not meant to be open to the elements and it would be better to start from scratch.

 

[pdenni]

hello ok

so you say the cable runs on the outside of your house, this is not to regs and is potentially dangerous if it is not protected, thats the first point
The easiest and most effective way of connecting outside lights is by connecting a switched fuse spur from the upstairs ringmain and either putting the cable in trunking above your skirting board from the next light or running externally in conduit, either way the lights should be rcd protected, so probably not as straight forward as you thought.,

 

[dingbat]

... either way the lights should be rcd protected...

A common misconception.

The requirement is that external equipment that has accessible exposed conductive parts have a reduced disconnection time of 0.4 seconds. (471-08-03)

 

[pdenni]

i take your point dingbat

But surely anything external as good practice you would ensure was rcd protected.For yours and the customers peace of mind

 

[dingbat]

Following the regulation requirements is good practice. A BS EN 60898 MCB will disconnect in 0.1 secs provided the EFLI is below the prescribed maximum. As far as protection from indirect contact is concerned that is more than good enough.

Adding an RCD will give supplementary protection against direct contact, but only an idiot is likely to come into direct contact with live parts of fixed equipment.

My objection is not on the grounds of belt and braces safety but on the dissemination of incorrect advice. This is how such things as 'cross-bonding' of sinks and central heating boilers become folkloric 'regs'. A whole stack of mythical regulations abound and are accepted without question.

I just think it's inadvisable to suggest things in a way that makes personal preference sound like a regulation.

 

[ColJack]

while i get your point, the regs are not statutory and are in themselves only a "sugested" way of doing things..

sometimes the "best practice" methods advised here are much better than the requirements that the regs sets down to ensure safety..

cross bonding of boilers is usually to manufacturers specs..
as is rcd protection on showers.. etc..

 

[Adam_151]

I just think it's inadvisable to suggest things in a way that makes personal preference sound like a regulation.

Heres one for you, Ding... which regulation says that a main bond cable must be a single unbroken length?