24th January 2022
Metal Trunking is used to house electrical cables. It’s often hidden behind plaster within walls or underneath flooring, and helps keep everything in the position you placed it.
As well as cable management, there are also safety features to Metal Trunking, as it houses the electrical current and stops the spread of fire if a fault occurs. Trunking is both a practical and regulatory aspect of electrical installations.
Metal Trunking is designed to keep all your cables in one place, while Conduit takes specific wires off to different appliances. For example, you’ll find Trunking behind the walls of a kitchen, but Conduit will take electricity to things like the oven and fridge.
Choosing the right size of Trunking comes down to two main things: the amount of cables you need to store, and the amount of space those cables will take up. If you put too many cables in Trunking, you risk overheating them when the power is switched on, potentially blowing your fuses or causing a fire.
As a general rule of thumb, no more than 45% of your Trunking should be occupied by cabling.
To work out the space your cabling will take up, you need to calculate the cross section of each cable and its insulation. You’ll also need to know the thickness of the Trunking.
Once you know this, you can work out how large you’ll need your Trunking to be to allow ample space for the cabling.
To cut metal Trunking, it’s as simple as having a good metal cutter and an angle to cut along. For most angles you can just draw a line along the corner you want to put in, but for a 45 degree angle you’ll need to do a bit of maths.
First, work out a 90 degree right angle at the point of the Trunking you want to cut. Then find the middle point of that and mark it on your Trunking. Draw a triangle between the top point of the angle and the 45 degree points either side.
After this simple process has been completed, your Trunking will be ready to use. It is important to be mindful of sharp edges after cutting Metal Trunking.
Yes you can. So long as you use a bonding coat, you can plaster directly over Trunking, keeping cables hidden and out of reach. Whether it’s Trunking or conduit you’re looking to plaster over, you should always make sure they’re deep enough in the walls to be covered by a full coat of plaster.