Phase Segregated

ATEX, IECEx & UKCA certified
Ex eb // Ex ec


Our best seller, an ATEX/IECEx/UKCA certified terminal box designed to eliminate phase to phase faults. Developed in the mid 1960’s by our previous heritage organisations which include; English Electric, AEI and GEC Large Machines Ltd. We have ensured that the phase segregated terminal box today is suitable for operating in a Zone 1, Zone 2, Zone 21 and Zone 22 gas and dust hazardous areas.

The Phase Segregated terminal box has been fitted to over ten thousand machines globally since its inception and today is sold to major OEM’s for new machines, as well as to other service organisations for retro-fitting.

Technical Description

The phase segregated terminal box comprises of a fabricated steel casing welded to a heavy gauge back and front plate. The outer steel case encloses an inner fabricated steel shell and steel barriers extending from top to bottom of the inner shell. The terminal box has three distinct segregated phase compartments, each completely shrouded by steel walls which are solidly connected to earth. The presence of the inner skin prevents an internal arc from flame cutting a hole in the outer casing, preventing hot gases discharging into the atmosphere with consequent danger to personnel.

As an additional safeguard, the terminal is enclosed within glass reinforced plastic moulded type enclosure. Cables from the equipment interior and the intermediate cables pass through moisture tight compression glands in the enclosure. Gaskets prevent the ingress of dirt or moisture. Each compartment is fitted with a desiccator unit which provides a visual indication of moisture within the box in any phase. The desiccator unit can be renewed while the equipment is energised.

Phase Segregated terminal boxes eliminate phase to phase faults. In the event of a fault developing between phase and earth in one of the glass reinforced plastic terminal enclosures, the rapid build-up of pressure will cause the enclosure to fracture across the rear wall, thus releasing hot gases and flame into the steel phase segregating compartment. If the fault energy is low it is likely that the fault products will be contained within the compartment. If the fault energy is excessive, then the relief disc will fail and the fault product will pass into the equipment interior where it will rapidly cool and disperse.

Spares Support

A full range of spares to support this terminal box assembly are available.  

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