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Low Voltage Garden Lights - How Do I Connect Them Safely?

Low Voltage Garden Lights - How Do I Connect Them Safely?

Thinking about 'low voltage' garden lights, how to connect them together and then connecting them all to the 'mains' supply may be confusing to many people.

Hopefully the following explanation helps a little.

For safety, the key is to understand that 'mains' wiring in the UK is typically installed to supply electricity at 230V-240V.  At 230V-240V the electricity isn't safe to touch and fatal shocks can quickly occur.  Nearly all UK modern house appliances use 230V-240V to operate and are typically insulated and fused to prevent electrical shorts and shocks occurring.

However, with our 12v low-voltage lighting the electricity is typically no stronger than that used to power a child's Scalextric or toy railway set!

Question: Does '12v low voltage garden lighting result in weaker lighting and illumination?

ANSWER: No, not at all.  It means normal lighting but powered by very safe electricity!  (You can check out the specification of light emitted on any of our products in the product summary.)

Firstly, all our garden and outdoor lighting products (cables, connectors, LED's etc) utilise very safe low voltage (12v) electricity and not the dangerous 230V-240V 'mains' electricity found in the UK. 

(The LED's are also extremely energy efficient with an equivalent energy usage that is typically ten times less than incandescent lights. The benefits of low voltage lighting can bee seen here )

Secondly, it's important to understand that each manufacturer design their specific lights, cables, connectors and fittings to be connected easily.  They then become simple to fit and they know they'll work seamlessly.

Techmar Three Way Plug & Play Connector

It'd be totally wrong to assume you can go to a local DIY store and buy a low voltage light fitting because you like the shape, colour, finish or price in the hope that it will be able to connect to and work with the leading brands we sell.  There is no international standard for connectors and cables and each manufacturer has developed their own products.

(Lots of people are replacing their old, tired and broken 'RING' manufactured lights and we can advise and help in that regard.)

(Our plug & play connectors and accessories can be seen here


Thirdly, it's important to remember that as they've developed their own methods of connection, whilst all are simple to install they're not designed to be interchangeable between manufacturer e.g. a Techmar transformer won't connect to a Konstsmide cable.  Put another way, Techmar lights work with Techmar fittings; and Konstsmide lights work with Konstsmide fittings etc.  

But the regular question is "How do I safely power the lights if they are not 'mains' driven?".

The answer is that the safe 12v electricity is produced through a simple electrical transformer.

It's the transformer that's connected to the dangerous 230V 'mains' power supply.  Simply put, it takes 230V 'mains' electricity and reduces it to 12v safe electricity.

Sure, it's true that to power a large number of lights you'll need a transformer with a bigger electrical output (watts) but it'll always supply the electricity at 12v!

Techmar Transformer

So every 12v powered garden and outdoor light system in the UK will always have at the very beginning of the lighting run at least one 12v transformer!

(Our transformers can be seen here

The next question asked is "OK, but where can I plug-in the transformer to take the 230V mains electricity and convert it to 12v safe electricity, and how do I connect the transformer to the light system?"

The answer is broken into two parts:

1 The transformer has a cable with a standard UK EC approved 'three pin' plug.  That plug is simply 'plugged' into either...

...a normal 'house' socket in the same way as you would plug a kettle into the house socket (for example in a garage, shed, outbuilding, conservatory, porch etc) OR a waterproof 230V connection point if it's outside

2 On the other side of the transformer is the 'output cable' or connection point for the 12v cable.

So the questions nearly always boil down to... 

Where does the 230v 3-pin electrical socket for your transformer plug need to be? 

The 230v 3-pin socket can be either indoors or outdoors.  

If it's outdoors then it should be encased in a waterproof casing/socket box as the plug attached to the transformer needs to be waterproofed.  

An example of a waterproof socket box is shown below and they can be obtained from places such as B&Q, Screwfix or Toolstation or your local electrical supplier.

What do you mean by a waterproof electrical socket box?

The image shown below is a waterproof electrical socket

230V 2 Gang RCD Switched Socket Housing

The image is from the Screwfix catalogue (BG Nexus 13A 2G RCD Switched Socket ) but equivalents are readily available from good electrical wholesalers.

An RCD is a residual-current device, or residual-current circuit breaker (RCCB), is a device to quickly disconnect current to prevent serious harm from an ongoing 230V electric shock.

All our transformers are weather proof but we just think it's good installation practice to house them.  It keeps the British weather off the transformer's casing and cables; and just helps tidy the view!  You can paint the boxes too if you don't like grey!

We use simple weatherproof boxes (e.g. from Screwfix - IP55 Enclosure) but again readily available elsewhere. 

IP55 Weatherproof Housing Box

NB: If you leave the transformer outdoors, whether or not it's housed, make sure it's lifted and fitted well off ground to avoid being flooded or buried in snow; and use common sense when near to water bearing fittings such as down pipes, leaking gutters, ponds etc.

The final question often asked is "Do I need an electrician?"

The short answer is you should only need a qualified electrician to install and certify (for Building Regulations) any new 230v cabling and sockets.

If you have existing 3-pin sockets (indoors or watertight outdoors) then you can simply plug the transformer into one of them.

Running the 12v lighting cable after that is then a simple and safe process and needs no electrician.  For clarity.  If you can plug one of our 12V transformers into a 230V socket then the cabling will be totally safe downstream of the transformer.

For smaller outdoor projects we provide a free advice and design service (see ).

If you have a larger project or just want to aska question about installation just give us a call (UK +44 (0)121 416 0408) or email us at  We can discuss what you're trying to achieve and we're confident we'll take the ideas you have to something you'll like and enjoy for a long time!

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