Replacing an outside light -help!

[Lusi83]

The old outside light was rusting away so I've just bought a new one. I thought a pretty simple job - but...

The old light was connected to a 'mains' grey cable (with earth) using insulation tape (not a junction box) and there is no conduit through the wall - doesn't seem too professional.

But the light switch box contains 3 switches (one for this light, one for the hall and one for the landing/stairs - this one can also be operated from a separate switch upstairs). This does seem to be original. The house was built in the early seventies and as far as I know hasn't been re-wired. The consumer unit is one of the old type - with push in fuses - you replace the wire.

The fitting instructions for the new light (PIR one) says 'electrical supply must be protected against short circuit by a suitable rated fuse (3 or 5 amp fused connectuion unit ) or a miniature circuit breaker not exceeding 16amps. This product should not be wired directly to a ring main.

Does anyone have suggestions? I have no idea where the wire runs and can't just replace the switch with a fused one. Is there another way - putting some type of fuse into the wire before connecting it to light? (there is quite a lot of spare wire you can pull out the wall) And would would happen if I just connect up the new light and not worry about it?
Help.....I can't put the old one back ( it fell to pieces) - so have the wires wrapped in insulation tape stuffed into the hole in the wall- not very weatherproof...and its raining...

 

[Adam_151]

Your lights should be on a five amp circuit (white spots on the fuse) already...

 

[securespark]

Unless it's a 500W flood....

 

[Lusi83]

Sorry for being thick - but does that mean I can just use the existing wires ...is a ring main different from a lighting circuit?
It's not a 500W halogen security thing - its a max 60w bulb, fake lantern thing with PIR

 

[Paul Barker]

Needs .4s disconnection time which internal lighting doesn't require but ring main does. I'm only a plumber though. I would think that a fcu off the ring main appropriately fused would do, and make sure the t n e is protected from UV rays, where it comes out of wall put a u bend on it so that rainwater runs off it and not into the hole in the wall. I expect there is a sparkie term for what for want of a better name I am calling a u bend.

 

[Lusi83]

Thank you all for the help...

Have now got (pregnancy) brain into gear and understand what you were telling me.... I'm very nervous about electrics - a flat I rented years ago burned down because of an electrical fault -I was out at the time but if I had been there and alsleep I would have been trapped five floors up...

Wired it into existing wires - if it blows the fuse in the consumer unit I'll live with it...
Thanks again

 

[Adam_151]

Needs .4s disconnection time which internal lighting doesn't require but ring main does.

Supprised a plumber knows that (though IIRC re: the s/o, you can have 5 secs if you keep touch voltage below 50v - but stick to making them discon. in 0.4 and thats fine and good )

I'm only a plumber though. I would think that a fcu off the ring main appropriately fused would do

I'd be supprised if the existing supply didn't meet the requirements for 0.4 sec disconnect, but as the OP wont have an ELFI tester we can't know

where it comes out of wall put a u bend on it so that rainwater runs off it and not into the hole in the wall. I expect there is a sparkie term for what for want of a better name I am calling a u bend.

I'd call that a drip loop

 

[Paul Barker]

Thanks for the extra help, I welcome you good folk puting me right I am only touching the surface and welcome a little guidance.

Paul

 

[didthathurt]

Needs .4s disconnection time

A .4s disconnection time is only req, IIRC, for socket outlets (413-02-09) and kit installed outside the earthed equipotential zone (471-08-03) - from the OSG, so I think I've got the actual reg numbers the right way round, I'll have a look in the 16th Ed later. This means, that a light, fixed to the outside of the house, connected into the house earthing system, needs a 5s disconnection time.