12v outdoor fairy lights

details

• 12v outdoor fairy lights
• 20m in length,
• coaxial socket
• UK 240v plug that with built in 12v 1amp transformer
• 220v-plug/12v-transformer has cable out with coaxial plug connects with coaxial socket on 20m fairy lights

Problem is I want to plug this in far away from the house say 10m-30m away, I dont want to take out a 240v extension cable out into the garden as that defeats the purpose of have 12v outdoor electrics.

Can I buy say a 1amp 12v transformer and keep that inside the house and run a cable out into the garden and basically cut the coaxial socket off the existing plug/transformer and connect that to this new graden cable supplying 12v 1amp of power?

OR, just cut the cable of the existing transformer and extend it?

Judging by what is printed on your power adaptor (which I can't read clearly!), it is not a transformer, but a DC power supply.
I would use that adapter you have, not replace it.

You could extend the 12V lead with flex, I'd suggest say 1mm cross section conductors to avoid too much voltage drop.

If you add the extra length of wire in the adapter cable, you will have at least one join, and the 'co-ax' plug and socket, outdoors, which could reduce reliability, depending on how you protect it.
But if you extended the wire at the lights, you could keep the plug/socket and adjacent joint indoors, and have just one joint outside.
However it might be easier to splice into the adapter wire, and just make sure your outdoor joints are well protected.

The connections of your extension cable need to be kept the same way round as they are now - don't inadvertently reverse the connections!

It possibly will work just extending the cable before it gets to the lights.

I would cut each core a couple inches apart from each other, and get 2core with one core marked to keep the polarity.

You’ll end up with 2 joints, but they’ll be fine taped up well. It’s only 12v

I might be concerned with volt drop. The lights might be dim, as they’re not getting full 12v or they might be full bright and pulling more amps that the power supply can manage.

A lot of these lights now come with warning labels saying not to extend the strings…. But that might mean not to add more actual lights to the string.