Why install an electrical wiring harness?
The advantages of an electrical wiring harness
An electrical wiring harness considerably simplifies the installation of the electrical network in a new building or during electrical renovation work. Among its many advantages, an electrical wiring harness is more economical and quicker to install than a conventional installation. The wiring harness is designed in advance, and the equipment required for installation is generally supplied in the kit. All you have to do is install it. An electrical wiring harness can save up to 50% compared with a conventional electrical installation.
How it works
The electrical wiring harness, also known as an “electrical spider system”, is created from the electrical installation plan or the construction plan of your home.
It consists of a junction box, known as a “central junction box”, from which electrical wires run. These cables inside ICTA conduit supply the electrical and lighting points in the rooms of the dwelling. One conduit runs from the central junction box directly to the electrical panel. Each conduit is identified by a label whose marking indicates the element it is intended for, namely:
- P for socket,
- L for light,
- I for switch.
You will find this reference on the electrical installation plan supplied.
Before installing an electrical wiring harness
Prepare the necessary equipment
Before installing the electrical wiring harness, you need to prepare the necessary equipment. You will need flush-mounting boxes for the cable outlets, and electrical accessories such as sockets, switches or light fittings. The flush-mounting box, like the DCL box, allows an electrical accessory to be fixed to the wall and ensures the safety of the electrical installation. Electrical wiring harnesses are generally supplied as ready-to-install kits. All the equipment required to install the electrical wiring harness, including flush-mounting boxes, sockets and DCL boxes, is included in the kit.
The electrical wiring harness layout plan and installation guide are also required to carry out your installation. You will also need an electrical panel. Most wiring harness manufacturers supply an electrical kit so that you can carry out the installation work.
Finally, equip yourself with a few DIY tools such as a screwdriver, pencil and wire strippers.
As with all electrical work, remember to switch off the power before carrying out any work to avoid the risk of electric shock or fire.
How do you install an electrical wiring harness? 6 steps to follow
Step 1: deploy the electrical wiring harness
To visualise the electrical wiring harness more clearly and make installation in the suspended ceiling, loft or hollow-core floors easier, start by laying it out on the floor.
Then distribute and orient each ICTA conduit according to the electrical accessories it needs to supply. Use the electrical installation plan and the labels on the conduits to help you. Each conduit is labelled to indicate which element it supplies. These references tell you what the electrical conduit should be connected to.
Finally, position the centre of the wiring harness at the location shown on the plan and secure it.
Step 2: secure the junction box
The second step is to secure the junction boxes (sometimes called “connection boxes” or “connector boxes”). Using a screwdriver and wire strippers, connect the electrical wires emerging from the conduit to each box. Be careful to follow the colour codes for electrical wires to avoid the risk of electric shock.
Step 3: route the conduits through ceilings and partitions
After securing the centres of the wiring harnesses to the ceiling, route the electrical conduits, one by one, through your ceilings or partitions to the end points where they will supply the electrical accessories. A single conduit may contain several electrical wires intended to supply different accessories. In this case, cut the conduit and pull out the electrical wires intended to supply the flush-mounting box. Take care not to cut or damage the wires when removing them from the conduit.
One of the conduits in the wiring harness is intended for connection to the electrical panel.
Note that electrical wiring harnesses can be positioned in various construction voids, suspended ceilings or unused parts of a sloping ceiling. You can therefore connect a connector box at the centre to connect a light fitting, for example. Once the plasterer has finished the suspended ceiling, you can fit the finishing cover and hang the light fitting from it. If necessary, you can access the central junction box.
Step 4: wire the electrical accessories
You can now wire your electrical accessories: sockets, lighting points, etc.
To find the drilling height for your electrical devices, refer to the installation plan supplied by the electrical wiring harness manufacturer or electrical company.
Be careful: installation of the electrical wiring harness must comply with the standards in force.
The NF C 15-100 standard regulates low-voltage electrical installations and specifies the height of flush-mounting boxes:
- Switches must be installed at a height between 90 and 130 cm.
- The centreline of 16 A power sockets must be positioned between 5 and 130 cm above the floor.
- For 32 A sockets, the minimum specified height is 12 cm above the floor.
Step 5: connect to the electrical panel
At this stage, you have almost finished your electrical renovation work. You now need to connect the wiring harness to the electrical panel so that it can distribute electricity throughout your home.
The electrical panel is generally already installed in a Housing Technical Duct (GTL). The enclosure may be pre-equipped or pre-wired.
Step 6: obtain Consuel approval
Consuel approval is essential to certify that the electrical installation complies with the standards. Go to the Consuel website and obtain the “yellow” Certificate of Conformity for residential or equivalent premises. An appointment will then be arranged to check the conformity of your electrical installation.
Electrical installation work is not the easiest to carry out. You can of course install the electrical wiring harness yourself, but you can also use a professional who will support you through every stage of your project.
The prefabrication of electrical wiring harnesses is an essential solution for building professionals, electricians and electrical wiring harness manufacturers. To manufacture a wiring harness, they use sheath pre-wiring machines that optimise the insertion of wires into conduits. The industrial pre-wiring machine therefore avoids tedious steps such as manually pulling wires through conduits.
