View Full Version : Any electricians on here?
Geodude
22-01-12, 07:34 PM
Just trying to understand how this batten lamp holder is wired
http://i866.photobucket.com/albums/ab227/geodude_album/DSC00081.jpg
http://i866.photobucket.com/albums/ab227/geodude_album/DSC00080.jpg
I have a new one to go in its place but the new one has N, loop and L?
Sid Squid
22-01-12, 08:00 PM
It isn't clear which one as they're not marked, but one of those pairs is a live and neutral supply, and the other is the switch line, one wire of which goes to either terminal of the switch.
On your new fitting the two reds will go together in the 'loop in' terminals, and one of the black wires will go to the 'L' and the other to the 'N'.
It will therefore be seen that one of the black wires is the return from the switch and is live, and should be suitably marked to identify it as such.
Please tell me you're going to cut the cabling back a bit and remove the bits with the duff insulation, and that you're going to sleeve and connect the earths neatly.
The Idle Biker
22-01-12, 08:03 PM
How is it wired?........badly!
Geodude
22-01-12, 08:08 PM
Thanks sid, yeah it will be done right as you can see the old one blew and had a bit of a melt! Wiring diagram came with the new fitting but i was unsure of how to go forward as the old one is wired so differently and has no loop?
DarrenSV650S
22-01-12, 08:09 PM
As sid says. The black with the nick in the insulation is most likely the switched live, and the one on the right probably the neutral, but you need to check obviously.
Has the red cable on the right got a nick in the insulation too? You need to fix all of those. Put some brown or red tape on the switched live.
The loop on the old one is where the two red cables are connected. It just isn't marked
daveyrach
22-01-12, 08:14 PM
Tell u how I found out which was switched live in my bedroom, turn electric off (obviously), then took switch face off and attached a 9v battery to the cables in the switch housing, then tested the cables in pairs at the ceiling pair wit around 9v is the cables to switch. Crude i know but it worked
DarrenSV650S
22-01-12, 08:17 PM
Tell u how I found out which was switched live in my bedroom, turn electric off (obviously), then took switch face off and attached a 9v battery to the cables in the switch housing, then tested the cables in pairs at the ceiling pair wit around 9v is the cables to switch. Crude i know but it worked
If you had a tester why didn't you just do a continuity test? :)
daveyrach
22-01-12, 08:19 PM
If you had a tester why didn't you just do a continuity test? :)
I know that now, this was a few years ago when i was a bit wary of electrics was first thing that sprung to mind at the time :D
Geodude
22-01-12, 08:23 PM
If you had a tester why didn't you just do a continuity test? :)
Ive got a multimeter can i use that to find the switched live? if yes how?
DarrenSV650S
22-01-12, 08:27 PM
Ive got a multimeter can i use that to find the switched live? if yes how?
Yeh just make sure the powers off obviously. Put the tester on one pair of cables (the same twin and earth) and put the tester on the lowest ohms setting and get someone to flick the switch on and off. Should go from infinity to 0ish
Geodude
22-01-12, 08:31 PM
Nice one fella :D will give that a go in the morning. So is the pic i posted up some obsolete fitting now?
Specialone
22-01-12, 08:32 PM
No need to test the switch live is there?
Once youve identified the loop in lives and the nuetral there will only be one left lol
Is that rose made of bakelite? ;)
DarrenSV650S
22-01-12, 08:33 PM
Na just old and maybe a little brittle. Worth changing anyway
DarrenSV650S
22-01-12, 08:35 PM
No need to test the switch live is there?
Once youve identified the loop in lives and the nuetral there will only be one left lol
Is that rose made of bakelite? ;)
Yeh if you flicked the power on and tested between the lives and the two blacks you would find the neutral. That's how I'd do it tbh, but the tester method is safer ;)
Geodude
22-01-12, 08:35 PM
No need to test the switch live is there?
Once youve identified the loop in lives and the nuetral there will only be one left lol
Is that rose made of bakelite? ;)
Thats all gobbldeegook to me Phil :( its in me dads place so aye its old.
Geodude
22-01-12, 08:37 PM
Yeh if you flicked the power on and tested between the lives and the two blacks you would find the neutral. That's how I'd do it tbh, but the tester method is safer ;)
I like the safe method ;)
Specialone
22-01-12, 08:41 PM
Thats all gobbldeegook to me Phil :( its in me dads place so aye its old.
Electrical rose connectors and switches etc were originally made of bakelite, a highly brittle material.
If you're interested (http://en.wikipedia.org/wiki/Bakelite)
Yours look that old ;)
Geodude
22-01-12, 08:47 PM
I meant this bit was gobbldeegook 'Once youve identified the loop in lives and the nuetral there will only be one left lol' and yeah ta for the wiki link :)
Geodude
22-01-12, 08:51 PM
Oh and btw thanks lads, you're a cracking bunch :D
Specialone
22-01-12, 09:00 PM
I meant this bit was gobbldeegook 'Once youve identified the loop in lives and the nuetral there will only be one left lol' and yeah ta for the wiki link :)
Oh :smt003
http://www.diydoctor.org.uk/project_images/electrical_safety/ceiling_rose.jpg
Ignore the next light wiring. Remember to isolate the mains power. Switching off the light at the wall switch still leaves you the live in the rose.
timwilky
23-01-12, 07:49 AM
Looking at your photos
I would guess the cable entering from the lower left is the live feed, neutral return and earth. Check with a meter. the central pair is the switch feed and switched live.
whoever fitted wiring like that with the poor tape, lack of earth shroud and nicks in the switch cable should be attached to it by his crown jewels. That was asking for trouble.
Main issue is likely to be have you got enough loose to pull and do the job properly. And with old fittings like that what is the condition of the rest of the wiring like?.
They do not look like perishable rubber insulation that flakes off as soon as the cable moves. But I would be checking what other horrors are in the other house fittings.
My grandparents bedroom lighting was flickering once and when I checked it out, literally all the wires were bare due to an old chalky type insulation that disintegrated as soon as you disturbed it. Was a nightmare!
If the roof space is above the ceiling he might be able to feed some extra cable down. At my last house they'd run the cables across the joists but still attempted to board it out slightly which almost cut through the cables. Cowboys everywhere.
Geodude
23-01-12, 11:49 AM
Well job jobbed. Fitting and wiring replaced (multimeter tip helped alot ta) and earth sleeve fitted as cable had melted at the pendant. I think it must have been a loose conection as my dad told me it had been flickering and buzzing for a while and he gave the fitting a bit of a wiggle and bang. So to all involved in the guidance a very big thanks. Could not have done it without your help, you guys are awesome and i owe you all. :D
DarrenSV650S
23-01-12, 06:27 PM
Good work :thumbsup:
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