Home :: 12v & 240V Outdoor Lighting Installation - FAQs

12v & 240V Outdoor Lighting Installation - FAQs

Lumena offer a wide range of 12v and 240v garden lights. Below you will find all you need to know to ensure your outdoor lighting system is wired correctly, general information and FAQs on low voltage lighting, including full wiring instructions.


Is 12v lighting safe to use?

12 volt systems are instrinsically safe and will not give an electric shock if wrongly wired, short circuited or damaged.


Do I need an electrician to install my outdoor lighting?

Mains 220-240v AC systems:  Essential! All additional permanent wiring, with the exception of very minor work, must be notified to the local Council building control department, or an electrician who is registered with one of the Government-approved “Part P” schemes must carry out the work. This electrician will then take care of all of the necessary procedures and will provide you with a certificate that confirms the work meets Building Regulations / BS 7671. It is best to find an electrician who is experienced in outdoor installations as they can be more complex than indoor and involve armour plated cable which is more complex to work with than normal household wiring cable. If installation is carried out by somebody who is not a registered competent person, the use of registered third party to certify notifiable electrical installation work is acceptable as an alternative to using a building control body for the entire installation.

Some minor work outdoors, such as replacing an outdoor light which is already connected to an existing circuit, is not currently notifiable (June 2016). Local Council will always be happy to advise whether or not specific work is notifiable so do check if in doubt!

12v AC systems: Recommended to use a qualified electrician but if the lights are not permanently / directly hard wired into the house wiring circuits then it is permissible for a DIY installation. To qualify for a temporary installation, the transformers must be able to be unplugged from the external waterproof sockets, or an indoor socket such as in a garage or shed. Any mains outdoor waterproof sockets must be installed by a qualified electrician.


What happens if I damage the cable whilst gardening?

Mains 220-240v AC systems:  Recall your electrician to check it out and replace any damaged cable. 12v AC systems: If it is 12v Rubber cable which has been damaged, that particular section can be cut out and replaced with new H05RN-F rubber cable relevant to your specific circuit (usually 0.75mm or 1.5mm). Use IP65 rated cable connectors to join the new cable to the existing circuit.


Can wild animals such as mice, rats, foxes chew through the lighting cable?

Unfortunately, the answer is yes, but it is rare if the cable is buried or if it is mains armoured cable as the metal surround is designed to protect the inner cables in situations such as this. To prevent damage from animals and protect the cables further, especially 12v H05RN-F rubber cable, the use of “Blue” heavy duty plastic water pipe to cover the cable or other suitable outdoor cable protectors is recommended.


Can Lumena 12v garden lights be wired directly to the mains power supply?

All Lumena 12v garden lights must be wired into a transformer. The transformer can then be plugged directly into the mains, or hard wired in the 3 pin UK plug is removed, which then converts the input mains voltage to an output of 12 volts. If a transformer is not used, the circuit will not be safe and the lights / sensors will blow.


How can I easily join several cables together when there are several lights in the system?

Use a waterproof junction box. The use of heavy duty “choc block” connectors inside will make it easy. If there are too many wires to fit inside each terminal / connector then more than one can be connected to one another using some solid insulated wire, like a “daisy chain”. Also some Plug and Play systems have easy plug in connectors but their use may be limited and they may restrict the type and make of lights that can be used. Lumena lights stock Eazylink 4 way and 8 way junction boxes which really are extremely simple and time saving to use.


Can Lumena 12v lights be wired in series?

No. It is very important that 12v lights are wired in parallel, which means all the same coloured wires should be connected together using a junction box, and not run from one fitting to another. Wiring in series will result in siginificant voltage drop and there will not be enough power in the circuit to illuminate the lights. It also means that is there is an issue within the circuit, any fitting located after the fault would also cease to work. This could be something as simple as bulb failure.


How do I wire my lights in parallel?

Easy to follow 12v wiring instructions can be viewed, downloaded and printed here, detailing how to wire your 12v lighting system in parallel using a "Wiska" Junction Box.


Should I use specific cable in my 12v outdoor lighting system?

Lumena recmmend and supply 2 core insulated rubber cable. For most applications 0.75mm² cable is sufficient, but for longer runs of over 20m, we recommend the use of 1.5mm² cable to reduce any voltage drop. In places of possible cable damage by rodents etc., we advise placing the cable inside flexible conduit for added protection.


Can I add sensors such as Photocell (dusk to dawn) and PIR (motion sensor) to 12v garden lighting systems?

Yes. There a couple of ways to do this, depending on where the sensor is to be located. If positioned after the the transformer, within the 12v wiring circuit, then a 12v sensor must be used. Lumena offer a range of outdoor photocell and PIR sensors in 12v. If located before the transformer, so within the mains power supply, a 220-240v sensor can be used, again available from Lumena. Wherever the sensor is positioned within the circuit, any subsequent fittings will be controlled by the sensor. Therefore, different areas in the garden can be connected to different sensors, e.g. motion sensors, so that a specific group of lights are triggered by one sensor, and another group / area by another sensor.