Replacing fitting which has old red/black wiring


Postby patrowles » Thu Oct 18, 2007 3:34 pm

The light fitting I plan to replace (3-lamp circular spotlight) currently has two pairs of red/black wires coming in through the ceiling and connecting to it via a standard plastic junction block, as follows: -

The live (red) from one pair is connected to the fitting's live junction
The neutral (black) from the other pair is connected to the fitting's neutral junction
The unused wire from each pair is connected to the third junction, with nothing coming out of the other side of the junction.

First off, is this safe as it currently stands? I assume one pair comes from the switch, which presumably means that the switch itself is not earthed.

If it is safe, can I just wire the new fitting (another 3-lamp circular spotlight) in exactly the same way? The new fitting has an earth terminal on it (on the chassis, separate from the live and neutral), and the instructions show the modern green/yellow earth cable connecting to it.

Much obliged for any help which can be given.
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Postby BLAKEY1963 » Thu Oct 18, 2007 11:55 pm

[quote="patrowles"]The light fitting I plan to replace (3-lamp circular spotlight) currently has two pairs of red/black wires coming in through the ceiling and connecting to it via a standard plastic junction block, as follows: -

The live (red) from one pair is connected to the fitting's live junction
The neutral (black) from the other pair is connected to the fitting's neutral junction
The unused wire from each pair is connected to the third junction, with nothing coming out of the other side of the junction.

First off, is this safe as it currently stands? I assume one pair comes from the switch, which presumably means that the switch itself is not earthed.

If it is safe, can I just wire the new fitting (another 3-lamp circular spotlight) in exactly the same way? The new fitting has an earth terminal on it (on the chassis, separate from the live and neutral), and the instructions show the modern green/yellow earth cable connecting to it.

Much obliged for any help which can be given.[/quote]

Patrowles
you have dated wiring possibly 40 yrs plus.
The current set up should not allow class 1 equipment to be connected. That is items with metal frames able to conduct fault current
at a dangerous potential with no earth fault protection.
It is not safe to connect up your fitting with current wiring set up
Your fitting requires an earth connection

BLAKEY1963 .
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Postby patrowles » Mon Oct 22, 2007 12:55 pm

blakey1963 - many thanks for taking the time to reply.

I have looked again at the wiring, and I did not describe the set-up with complete accuracy.

The pairs of red/black wires coming in through the ceiling do not connect directly to the light fitting; they go into a plastic junction block, from which a blue (neutral) and brown (live) wire then connect to the terminals on the fitting itself. So it is: -

Red 1 in to junction block, brown out to neutral terminal of fitting
Black 2 in to junction block, blue out to live terminal of fitting
Black 1 and Red 2 to same terminal of junction block, nothing out

My wife says that this is similar to several fittings we had in our previous place (also old wiring), and that these are "double insulated" and therefore safe (she might be trying to blind me with science!).

The existing fitting has a plastic housing and no earth terminal, while the new fitting has an earth terminal on the metal part of the housing.

Does any of this make any difference?
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Postby patrowles » Wed Nov 07, 2007 1:48 pm

Not looking to 'bump' this thread back up for the sake of it, it's just that I had an email from the site a few days ago saying that there had been another reply (i.e. other than the original one from blakey 1963).

However, when I clicked on the link in the email to view the new posting, I got a "thread not found" response. I navigated to the site and found the thread was still here, but my email to the site asking what was going on has not been acknowledged. Did anyone by chance have any more input?
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Postby sparx » Wed Nov 07, 2007 10:05 pm

Hi believe wifey she's right if other fittings were dbl ins then ok but as Blakey says if got an E term then can't be fitted unless an E is run in from another circuit or from con.unit
regards SPARX
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Postby patrowles » Thu Nov 08, 2007 8:54 am

SPARX - many thanks for taking the time to reply.
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