Every electrical installation has cables. Those cables need to be held in place, protected and kept in order. The equipment that does this is called containment.

Containment is the casing, brackets and supports that hold wiring and plant equipment. In a commercial or industrial building it is the backbone of the whole installation. It is also usually the most visible part of the job, so it says a lot about the quality of the work.

The main types

Cable tray: a flat, perforated metal tray that cables are laid on and tied to. Good for carrying lots of cables along walls and ceilings.
Cable ladder: like a tray but shaped like a ladder, with rungs. It is stronger and is used for large, heavy cables over long distances.
Cable basket: an open wire mesh tray. It is light, quick to install and often used for data cables.
Trunking: an enclosed metal or plastic channel with a removable lid. It hides and protects cables, and makes it easy to add more later.
Conduit: a metal or plastic tube that cables are pulled through. It gives strong protection where cables could be damaged.
Supports and fixings: the brackets, rods and strut channels that hold everything up.

Why it matters

Good containment does several jobs at once.

Protection. It keeps cables away from sharp edges, heat, moving machinery, forklifts and people.
Support. Cables are heavy. Without proper support they sag, strain their connections and can be damaged over time.
Separation. Power cables and data cables should be kept apart so they do not interfere with each other. Containment makes that easy to do and easy to see.
Safety in a fire. Containment needs to be fixed so that it will not collapse and block escape routes if there is a fire.
Easy maintenance. When cables run in clear, labelled routes, an engineer can trace a fault quickly.
Room to grow. Well-planned containment leaves spare space, so new circuits can be added later without starting again.

Rules and standards

In the UK, electrical installations must meet BS 7671, the British Standard for wiring, often called the IET Wiring Regulations. It covers how cables are selected, installed, supported and protected, and containment plays a big part in meeting it. Metal containment also needs to be earthed properly where the design requires it.

Planning containment well

Containment works best when it is designed early, alongside the rest of the building services. Pipework, ducting, lighting and sprinklers all compete for the same space in ceilings and plant rooms. Planning the routes together avoids clashes and last-minute fixes.

The choice of material matters too. Galvanised steel is strong and suits most commercial and industrial buildings. Plastic trunking can suit offices and lighter-duty areas. Outdoors or in damp places, the material needs to resist corrosion.

Why we treat it as a craft

We treat containment as a craft and an aesthetic feature of all our installations. Straight runs, neat bends, consistent fixings and tidy cable dressing make a plant room or ceiling easier to understand, safer to work in and better to look at. It is a detail that shows how much care has gone into everything else.