20A 4 Terminal Junction Box - Black 79mm

The Knightsbridge 20A junction box houses four brass terminals inside a 79mm diameter black thermoset resin enclosure rated to IP20. The box is designed for permanent connections in lighting circuits, ring mains and socket spurs rated up to 20A on 230V mains, providing a fixed junction point where multiple cables need to be joined or branched within a circuit.

The selective cable entry system allows knockouts to be removed only where needed, leaving unused entry points sealed to maintain the IP20 ingress protection rating. The 26mm projection from the ceiling or wall surface allows sufficient depth for cable terminations and gives clearance for the four brass terminals arranged around the central mounting point. The resin casing resists impact and heat better than standard plastic enclosures, giving longer service life in ceiling voids, under floors and behind plasterboard.

Certification to BS EN 60670 confirms the enclosure meets European safety standards for electrical accessory boxes, covering mechanical strength, fire resistance and terminal retention under load. The black finish allows the box to blend into dark ceiling voids or be surface-mounted in utility areas, plant rooms and storage spaces where aesthetic integration is not required. Knightsbridge backs the box with a 25-year warranty.

Product Specification Sheet

What is selective cable entry?

The junction box has multiple pre-moulded knockout points around the perimeter. You remove only the knockouts where cables enter, leaving unused entry points intact to maintain the IP20 rating and prevent dust or debris entering the enclosure.

Can this be used in bathroom zones?

No. The IP20 rating means the box is protected against solid objects larger than 12.5mm but has no moisture protection. It is not suitable for bathroom zones or outdoor use. For wet areas, use a junction box rated IP65 or higher.

What circuits is the 20A rating suitable for?

The 20A rating covers most domestic lighting circuits (typically 5-6A), socket ring mains (20A or 32A depending on protective device), and radial socket circuits. It is not suitable for dedicated cooker circuits or electric showers which typically require higher-rated enclosures or different junction methods.

What does the 25-year warranty cover?

Knightsbridge's 25-year warranty covers manufacturing defects in the thermoset resin housing and terminal assembly. It does not cover damage from incorrect installation, over-current loading beyond the 20A rating, or use in environments outside the IP20 specification.