Acceptable means of making a spare live conductor safe - inside external floodlight

[tlangdon12]

I've got an old floodlight outside my domestic property that I want to replace with a new Low-Energy unit. The new unit has no PIR, so just has a Live, Neutral & Earth connector inside the IP65-rated housing. The connector itself has push-buttons cable clamps a bit like cheap speakers have, so no chance of overtighening any screws!

The old floodlight was PIR-controlled, supplemented with a manual (override) switch from by the back door. A single cable (three-core plus earth) supplies the old unit. The red core is always live and feeds through the PIR, the yellow core is the switched live from the switch by the back door. The blue is the common neutral.

If I swap the old unit for the new, I'm going to have the red conductor left spare and I'm wondering how I should terminate it. I really don't want to have to pull the cable back in side the house and replace it with twin & earth as this will mean lifting the carpets and the floorboards to get at the junction box. Is there an acceptable way to make the spare live conductor save within the light fitting?

As you will guess, I'm not a registered Part-P 'Competent Person', but a capable DIYer. I understand that Part-P allows me to do this work without notifying building control because there is no external junction box involved.

Any advice appreciated - even "Get an Electrician in", if you can explain why.

Cheers

Tony

 

[telectrix]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

just terminate the red in a block connector to make safe, but be aware that even though the new light is switched off, there will always be a live there unless the MCB/fuse feeding the circuit is isolated.

 

[Guest123]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

Can you not disconnect the permanent live supply (red core) at the switch??? just leaving the switched live an neutral connected???

 

[nickblake]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

As telectrix has said but lable the perm live as perm live so people working on the fitting know know

 

[tlangdon12]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

Thanks

I think I have some chocolate block connectors somewhere. I'll use one of those and label as suggested by Nick.

 

[nickblake]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

Thinking about it i would probably use a wago push fit connector rather than a terminal block

 

[Deleted member 19807]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

as lenny says but spare cores should be connected to earth at both ends.

 

[Hawk81]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

as lenny says but spare cores should be connected to earth at both ends.

Why should spare cores be connected as an earth at both ends????

 

[tlangdon12]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

I've tried to analyse the wiring in the JB and would guess that it looks like this:



If this is the case, I don't understand how Lenny's answer applies?

I would guess hifly's point about spare conductors being earthed at both ends is so that in the event of a fault at one end of the conductor, the other end doesn't become live.

 

[Deleted member 19807]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

if its connected to an earth terminal at both ends you don't have any floating wires in chock blocks that you or the following person have to investigate further as to whether its live or not, you also don't have to use any extra components or find room in the enclosure for it. Also in the event of a fault of nail through cable one end can become seperated frrom the other and the unconnected end could be live without fuse blowing.

 

[Deleted member 19807]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

i would disconnect the red going to the light and terminate it in the earth connector and do the same at the light end end, sleve with g/y

 

[Sintra]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

Why should spare cores be connected as an earth at both ends????

It's common practice for an unused core of a multi core cable to be connected to earth to eliminate any induced voltage.

 

[amberleaf]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

Sorry Lenny for dropping in like This . Am very Sorry about this “ Warning “

PS. I don’t now where to drop this One ????

Postal Scam:Can you circulate this around especially as Xmas is fast approaching - it h=as been confirmed by Royal Mail. The Trading Standards Office are making pe=ople aware of the following scam:A card is posted through your door from a company called PDS (Parcel Delive=ry Service) suggesting that they were unable to deliver a parcel and that y=ou need to contact them on 0906 6611911 (a Premium rate number).DO NOT call this number, as this is a mail scam originating from Belize.If you call the number and you start to hear a recorded message you will al=ready have been billed =A3315 for the phone call.If you do receive a card with these details, then please contact Royal Mail= Fraud on 020 7239 6655.For more information, see the Crime Stoppers website:http://www.crimestoppers-uk.org/crime-prevention/helping-prevent-crime/scam=s/postal-delivery-scam

The Good Lady works for the Government . I’ll leave at that . Amber Sorry about this . Thank you Lenny .

 

[mechelec]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

It's common practice for an unused core of a multi core cable to be connected to earth to eliminate any induced voltage.

I seem to remember reading about unused conductors being earthed in one of the niceic snags and solutions books

 

[Guest123]

Re: Acceptable means of making a spare live conductor safe - inside external floodlig

I've tried to analyse the wiring in the JB and would guess that it looks like this:

View attachment 2904

If this is the case, I don't understand how Lenny's answer applies?

I would guess hifly's point about spare conductors being earthed at both ends is so that in the event of a fault at one end of the conductor, the other end doesn't become live.

What I assume the OP has is a L&N supply to a switch by the back door and then a 3C & CPC up to the outside light. The red is connected into the common of the switch with the perm live supply of the T&E, the yellow will be the switch wire in L1 with black & blue in a connector.

Hence my suggestion of disconnecting the red core.