UK Identifying live, neutral and earth in outdoor festoon lighting

[Richard Cook]

I bought some outdoor festoon lighting a few years ago and the 2 pin connectors (male and female) have corroded so I’m going to splice the connectors together using heat shrink butt connectors. Each run is 5m with a male and female 2 pin connector at each end. My first thought was that this would be a 2 min job but it turns out none of the wires are labeled so it’s tricky to work out which wires are live, neutral and earth once the connectors have been cut off.

See a few photos attached.

I can connect one end (thankfully the one end that isn’t damaged) to the “starter plug” which has a transformer (31v) so can voltage check each cable and plug it in.

At the other end, with the now exposed wires, what’s the best way to find the live, neutral and earth? I’ll then need to Wago, for testing, this to the other run but how do I work out which is live, neutral and earth on that run? Trial and error? What am I looking for? Would it trip the RCD until right? What about the transformer? Any way I can avoid breaking it with testing?

 

[Richard Cook]

If this helps...

 

[Avo Mk8]

I think you want combination No. 3, but the third wire for the second string (on the right) should go to -ve.

 

[Richard Cook]

I think you want combination No. 3, but the third wire for the second string (on the right) should go to -ve.

It works!!!

Can you explain what is happening? I kinda get it but just know if I was to do another run I’d get it wrong

+ve to +ve with the third wire
-ve to -ve with the third wire

Thanks so much for coming back and helping. Much appreciated.

 

[Avo Mk8]

Just logic!
The straight through +ve and -ve must be consistent throughout.
You had first, third and fourth strings working, so that must be the correct wiring of the 'straight through' supplies.
So that just left the input to the second string to be on the wrong side.

Going back to my crude drawing in post #42, we now know the upper straight-through wire is -ve, and the lower wire +ve.
And the third wire starts on the -ve supply and ends on the +ve.
Good result!

 

[littlespark]

Very well done in working out what goes where…
I think AVO has gone above and beyond with this one where many of the rest of us just decided “bin it!”

Now you have a festoon string that’s held together with wagos…

Maybe some of these? But check the right size… this was just first one I found

https://www.amazon.co.uk/Waterproof-Connector-Extension-Electrical-Protector/dp/B09WDLB9CR/ref=asc_df_B09WDLB9CR?tag=bingshoppinga-21&linkCode=df0&hvadid=79920879569851&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=m&hvlocint=&hvlocphy=&hvtargid=pla-4583520400071921&psc=1

 

[Richard Cook]

Now you have a festoon string that’s held together with wagos…

Maybe some of these? But check the right size… this was just first one I found

https://www.amazon.co.uk/Waterproof-Connector-Extension-Electrical-Protector/dp/B09WDLB9CR/ref=asc_df_B09WDLB9CR?tag=bingshoppinga-21&linkCode=df0&hvadid=79920879569851&hvnetw=o&hvqmt=e&hvbmt=be&hvdev=m&hvlocint=&hvlocphy=&hvtargid=pla-4583520400071921&psc=1

Yes! I had looked at these but with the three cables (wires) and not one single cable I didn't think they'd work as waterproof connectors as the seal would be round the single cable but with 3 wires there's room for water ingress?

I have heatshrink butt crimp connectors which would've been fine if each wire went to a single wire but as it's 2 to 1 on both sides I'm still not sure what would be best!

 

[Richard Cook]

Just logic!
The straight through +ve and -ve must be consistent throughout.
You had first, third and fourth strings working, so that must be the correct wiring of the 'straight through' supplies.
So that just left the input to the second string to be on the wrong side.

Going back to my crude drawing in post #42, we now know the upper straight-through wire is -ve, and the lower wire +ve.
And the third wire starts on the -ve supply and ends on the +ve.
Good result!

Thanks again so much for all your help – it's been a really fun process but of course 240v is not fun

 

[Avo Mk8]

If you'r happy to have a permanent joint (not a connector) there are epoxy or gel filled joint boxes that are waterproof, though a bit clunky! eg:

6A Gel Insulated Straight Through Joint - 3 Core Flex - IPx8 | Wiska (SH0325W)

 

[mainline]

One of those backlight Chinese testers may have helped that’s if the tester didn’t catch fire or electrocute you.

LED TV Backlight Tester 12W LED Strip LED Panel Single LED Bead COB Light Tester | eBay - https://www.ebay.co.uk/itm/294642898613?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=Yv_QNsB4RWO&sssrc=4429486&ssuid=urSTfeYDTiO&var=&widget_ver=artemis&media=EMAIL