Cost Of Installing Garden Lighting
A guide of the process for hiring a tradesman to install lights in your garden, including the costs of labour and materials.
This article will detail how to install mains-operated garden lighting and will outline the issues and pitfalls associated with doing this task.
Costs involved with installing a typical garden lighting system
Based on a system that has a total cable run of 65 metres, and 10 LED light clusters plugged into an existing inside socket, the cost will be approximately £120 to £160. If you want an outside 230V fitted, the price could rise by a further £100 to £150. If you use a transformer, it may add a further £30 to £60 to the overall equipment cost.
What installing garden lighting entails
The installing of garden lighting will include the safe siting of suitable lights and the placing of fully connected cabling to supply them. The total of cable required – together with ancillary parts – and the type and amount of lights needed will depend upon the area of the garden that you expect to cover. Installing garden lighting usually means fitting environmentally-appropriate lights at selected parts of your garden, connected and powered by either armoured cable or regular cable that is provided within a conduit.
First, you need to plan where you are going to locate your lights and determine the best routes to get the cabling to those sites. You should consider the positions of immovable things in the garden such as drains and trees, and either work around them or re-plan your light positions accordingly. You will also need to decide if you are going to use low voltage lighting with a power supply, or mains with a transformer.
Other jobs to tackle
Since you will be digging up much of the garden to install lighting and the associated cabling, this is an ideal opportunity to reconfigure your garden and tidy it up.
General advice when installing new garden lights
It is generally desirable to only consider systems that are termed as Extra Low Voltage (ELV) – usually defined as below 50V A.C. or below 120V D.C. The installations are far safer, simpler and can be less troublesome, providing you use suitable quality components. You can also use flexible cables, HI-Tuffs of comparable length for their fitting rather than armoured, and you don’t need to submerge the cables to a depth of at least 600mm as a safety feature.
If you can fit a larger 50-63mm duct between joint boxes, it’ll make extracting cables through easier. Ground-type allowing, submerging the duct 600mm will save it from being harmed later on. To ensure that larger animals such as foxes don’t get through your conduit, use a 10 or 20mm flexible conduit for the little, pre-installed flexi-connections on the lights.
Dealing with water ingress
Regardless of how well you seal everything, it is likely that you will get some water ingress over time and the lighting and cabling that you put in will have to be able to deal with this. Armoured cable is used in low voltage installs to ensure the fault current goes down the Earth to disconnect the circuit quickly and mean reliability will be best as the lighting can endure water in light fittings without initiating the safety device to trip.
Supplying the outdoor lighting
In 90% of instances, the outside lighting is additional to the building and is typically taken from an existing circuit through the kitchen sockets via a fused spur. This does give you ready access to the power switch, but makes it less of a permanent feature. Preferably, the supply to the garden lighting fitting should be an independent circuit so that, if tripping issues do occur, it doesn’t affect the rest of the installation.
Installing dedicated outdoor circuits
If you want to install dedicated outdoor circuits, then ground-type permitting, burying the duct 600mm will save it from being damaged later on. Cables half drawing out of joint boxes can be an issue. From an electrical position, if the fitting is LV and there are unprotected single insulated cores hanging outside of the box, then we have a possible hazardous installation. It also means water can enter and eat away the connections or initiate tripping. To ensure that larger animals such as foxes don’t get through your conduit apply a 10mm or 20mm flexible conduit for the small, pre-installed flexi-connections on the lights.
Building control guidelines
Unavoidably, the majority of light fittings will come in to contact with water. With LV, this will not only cause the light installation to break but also the circuit to trip. If ELV fixtures are utilised, then this problem will be moderated as a transformer or driver separates the supply. Electrical work within a garden that is rated as low voltage needs to be reported under Document Part P to Building Control for additions, alterations and new installations. The work will also need an electrical installation certificate if a new circuit has been routed, or a minor electrical installation certificate if there’s a change to a current circuit. If the fixture is completely extra-low voltage, then this may not be required.
Here is a list of commonly asked questions regarding installing garden lighting.
Q Is extra low voltage cable really safe?
Yes. You can slice through the cable with a spade without an accident; the most dangerous thing that can occur is the lights might stop working, and you may have to replace a transformer or driver.
Q Where does the 230v 3-pin electrical socket need to be?
The socket can be located either indoors or outdoors as is appropriate to your design. If it's outdoors, then it should be encased in a waterproof casing as the plug attached to the transformer needs to be waterproofed. If you are having an outside socket fitted, it will need to be installed and certified by a qualified electrician.
Q How far can I run a length of 12v low voltage cable?
Many systems have installed 12v low voltage cables for a distance of around 65 metres and at the end of the cable used three 30-watt LED floodlights for up-lighting some large areas of the garden. The layout has to be carefully considered and designed so that it is best not to assume that a 65-metre run will work as a maximum for everyone, regardless of the lighting that they are using.
It is possible to create longer runs - up to 90 metres, especially if the high consuming LED floodlights had been low consuming spotlights. For example, if you initially install 3 x 30-watt LED floodlights it equals 90 watts total. These can be replaced by 10 x 4-watt LED spotlights, to give a much lower total value of just 40 watts but without a significant lowering of the light output.
Q What is the difference between a transformer and a power supply?
A transformer provides A.C. output of 12 or 24 volts; 12 volts A.C. is normally used to power halogen lamps in low voltage garden lights. A D.C. power supply offers direct current output - similar to a battery - and is required for some LEDs. On the whole, LEDs consume a lot less power than incandescent lamps and are generally less sensitive to small voltage reductions. But note that LED’s are vulnerable to overvoltage, so you should usually use a regulated 12-volt D.C. power supply to ensure stable voltage to a small group of LED lights.