Electrical Junction Box

Name: Junction Box
SKU: ELE-0084

Product type	Junction box

Choosing and specifying this item

Junction boxes tend to be the last item specified and among the first to cause rework, because they get chosen by eye instead of from the connections they have to hold.

Size from the connections, not from the cable

Work out the number of conductors, the terminal blocks or connectors they land in, and the bending radius each cable needs once inside. A box the cables can enter but cannot be worked in is a box that gets replaced at commissioning. Where low-voltage circuits meet extra-low-voltage, control or data circuits in the same position, use separate boxes or one with a fitted barrier.

Metal or non-metallic changes your obligations

A metal box with metal glands becomes part of the earthing arrangement and needs a proper earth terminal and continuity across the lid. A non-metallic box removes that but brings temperature and ultraviolet limits - relevant in roof voids, on external runs and on rooftops - and its fire behaviour matters where it sits in an escape route or a ceiling plenum.

Confirm before ordering

Material and finish, internal dimensions, the ingress class the location demands, and the entry arrangement: pre-formed knockouts fix your entry positions, while an undrilled body lets you follow the containment but leaves the sealing entirely to your installation.

Compare the rest of the range in Metal Distribution Boards & Electrical Enclosures, Electrical. Related reading: MCB Trip Curves B, C and D Explained.

Frequently asked questions

Metal or plastic - how do I choose?

Start from the location. Metal resists impact and heat and suits exposed industrial and plant areas, but it becomes part of the earthing arrangement and must be bonded correctly, and its corrosion resistance depends on the finish in coastal air. Non-metallic boxes avoid corrosion and bonding work but carry temperature and ultraviolet limits and different fire behaviour. Confirm the material offered, since it is not held for this item.

How do I size a junction box properly?

Size it from what goes inside, not from the cable diameter. Count the conductors, the terminal blocks or connectors they land in, the space each cable needs to bend without stressing its insulation, and the room an electrician needs to work with a screwdriver. Then confirm internal dimensions rather than external ones, and check the entry positions suit the direction your containment arrives from.

Do junction boxes have to remain accessible?

Connections that are not of an approved maintenance-free type are generally expected to stay accessible for inspection and testing, and most GCC project specifications repeat that requirement. Plan box positions against ceiling access panels and containment routes rather than burying them above fixed plasterboard. Confirm the requirement in the project specification, because it governs both the box position and whether a maintenance-free connection method is acceptable.

What should I confirm before placing an order?

Material and finish, internal dimensions, the ingress class the position requires, whether entries are pre-formed knockouts or an undrilled body, the number and size of glands, and whether an earth terminal is fitted. None of these are held in the catalogue for this item. State as well whether the box sits externally, on a roof, or in a coastal location, since that drives the material and finish decision.