Flameproof Lighting

Flameproof lighting and equipment is contained within an enclosure designed to withstand the effects and resultant pressures of an internal explosion. The construction is heavy due to the thick wall sections and requires the use of flamepaths for flame cooling.

Enclosures for luminaires are constructed from engineering grade composite polymer materials to provide protection from impacts and internal explosion pressures. Earlier equipment used glass visors with wire guards, although these proved too vulnerable to flying coal pieces and accidental damage.

Flameproof lighting consists of four major components:

• Primary supply cable
• Isolator box (with or without switch)
• Secondary lighting cable
• Light assembly

The supply or primary cable is a hazardous location trailing cable with pilot protection circuits. It may be single or three phase. This cable is run along the face from the CME to the first isolator box and then looped to subsequent boxes mounted on the shields. To minimise voltage drop along long faces, this cable is often 10mm² or 16mm² (more common).

The isolator is a flameproof enclosure and houses the primary socket/s and terminal strip. The Burn Brite enclosure also houses fuses and power factor correction capacitor (if required). The fuses are necessary to provide isolation of faulty secondary cables and/or luminaires. They also serve to provide protection due to break of gauge from 16mm² primary to 1.5mm² secondary cables. These enclosures are a fabricated steel construction. In practice they provide convenient connections of a smaller secondary cable to the heavier (16mm²) primary supply cable.