We get a lot of phone calls and emails regarding how best to utilise your garden lighting cable. While we encourage this, after all we are here to help, we thought adding a garden lighting cable guide would be very useful to a lot of you.

Mains Cables

There are two types of main cables in the Techmar range. There is a 15m as well as a 10m. There are two common questions we get about cabling regarding the mains cable.

  1. Can you join two main cables together?
  2. Do I have to have a mains cable?

You can actually have 3 mains cables joined together resulting in 45m of cable which should be more then adequate for most peoples gardens. Remember and this is important when you join mains cables together, you lose the last connector because the mains cable you are adding will need to be plugged in. So for example, two 15m mains cables will result in 11 sockets/connectors and not 12.

Up To Three 15m Mains Cables Can Be Joined

Techmar Garden Lighting Cable Guide

What is the difference between SPT3 and SPT1 cables? 

The SPT3 cable is a larger cable (cable size 10mm x 5mm) and is capable of taking 150 watts of loading, whilst the SPT1 cable is smaller (cable size 5mm x 3mm) and will take a maximum of 120w. The smaller SPT1 is more than adequate in most garden lighting systems now when using energy saving LED bulbs. 

NB. It is always good practice, when using both SPT3 & SPT1 main cables in a continuous run, end to end,  to try to start with the bigger SPT3 and connect the SPT1 cables after. This helps reduce any potential problems with "volt drop" on longer cable runs that are approaching the system recommended maximums (as stated below) 

Manufacturers Maximum Main Cable Lengths

The recommended guidelines for joining cables is as follows:

LED Lighting - Up to 80m with a maximum load of 150W

Halogen Lighting - Up to 40m with a maximum load of 150W

We have however we have supplied systems that are much longer. Led based systems especially perform well using more cable. If you are in any doubt please call us for more help. 

Do You Actually Need A Mains Cable?

Well the simple answer is no. If you are for example, running a set of decking lights and your power supply is on or close to the decking, you can simply go from the transformer directly to the lights.

Extension Cables

Once you have laid out your mains cable around your garden, you are now in a position where you need to get that power to your lights. All lights in the Techmar range (at time of writing) come with either a 1m, 1,5m 2m or 3m cable. So for the most part this should be enough cable to reach your mains cable. But what if it's not? Well that's where the extension cables come into play. There are 3 in the range, a 2m, a 6m and a 10m.

The 2m and 6m are very useful for adding that extra cable for difficult to reach lights such as wall lights. The 10m cable is ideally used as a lead in cable. For example if you want your lighting at the bottom of your garden, you don't want all your connectors to be in the first 15m. So by putting a 10m extension cable between the power supply and the 15m mains cable will allow all your connectors to be in a more useful position. The 10m extension cable can also be used to reach very remote lights.

3 Way Splitter Cable

The last cable type after main and extension cables is the splitter cable. The three way splitter is used to increase the number of sockets/connectors available from one to three. This is very useful, especially if you have an area of your garden which has a number of lights. The three way splitter is also very useful for decking lights that don't connect together (daisy chain) although we will discuss that in more detail in the last part of this guide. You can also plug a splitter into another splitter to create even more sockets. This is really useful if you want a lot of lights bunched together in one area. 

Cabling For Decking Lights

When it comes to working out the cabling for your decking lights, it is important to point out that different up-lights / decking lights in the range connect together in different ways. All decking and up-lights except three use the standard configuration (shown below) as in each light has to be plugged in separately. We recommend using 3 way splitters to create enough connections for the amount of lights you need. The other 3 lights in the uplight / decking range (the astrum, the alpha and the axis) actually connect to each other. The last light in the chain can either be capped off or can be used to lead on to other lighting.

Lights Connect To Each Other (Daisy Chain)

Garden Lighting Cable Guide

Standard Configuration

Garden Lighting Cable Guide

Something For You To Be Aware Of

Techmar continually make improvements to their range. This sometimes results in the upgraded version of a light (although looking exactly the same) having a different length lead. So even if you have purchased a light from us before and are just buying an extra one of the same type, please double check the lead length stated in the product information in case it has changed.

Garden Cable Design Service

As we mentioned at the beginning of this guide, we really do like hearing from our customers, so if you have any questions please let us know. We also have a free cable design service which you can read about here.

Volt Drop

What is Volt Drop you ask? Well is where the voltage going through the light system drops the further it goes. This means that you could have a light or two, furthest away from the transformer, looking a little dimmer than the rest. If you tested the voltage at the furthest point of a big system. It would not be 12 volt, it could be 9 or 10 volts. Therefore, the reduced voltage may produce less light from the fittings towards the end. This was a much bigger problem in the old days for Halogen systems. To rectify this the manufacturer tests and produces LEDs that are designed to operate at full output with a reduced voltage input, thus eliminating Volt Drop on much bigger systems. This is not guaranteed as various things lead to Volt Drop, i.e system loading, transformer sizing and whether Techmar manufactured LEDs are being used.

If you are in any doubt, please call us as we have many years’ experience in designing and supplying systems.

Cable Sizes

SPT3 is approximately 10mm x 5mm (15mtr Main cable and 10m Extension cable) Max 150w loading

SPT2 is approximately 7mm x 3.5mm (Cable on 3 way dividers, Deluxe Bundles and 1 & 3mtr extension cables) Max 150w loading 

SPT1 is approximately 5mm x 2.5mm (8, 10, 15 & 25mtr main cable plus 2 and 6mtr extension cables) max 120w loading

We now offer a SPT2 plain cable system (available on our Deluxe Bundles and over the telephone). This is a great new system that is even easier to install as the cable is plain and can easily be feed through ducting, in between paving stone gaps and laid across lawns. Once the cable is laid, it can be cut to length, capped off and a heavy-duty female connector clamped on where you want a light to plug in. Available in 10, 25 & 50mtr drums with male and female connectors. It is fully interchangeable with the standard Garden lights range of lights, and accessories. Call us for a SPT2 cable plan today.