Explosionproof terminal boxes 'Increased safety e' (EPL Gb und Gc)

The explosionproof terminal are intended for use in Zone 1 and Zone 2 explosive gas atmospheres according to IEC/EN 60079-0 and IEC/EN 60079-7. IEC/EN 60079-7 ‘Equipment protection by increased safety e’ covers explosion-proof equipment for equipment protection levels ‘Gb’ (Zone 1) and ‘Gc’ (Zone 2) and the levels of protection ‘eb’ and ‘ec’.

Strict observation of the correct use of the levels of protection ‘eb’ and ‘ec’ is essential to ensure that equipment with the level of protection ‘ec’ is not suddenly installed Zone 1 areas. It goes without saying that equipment in both the type of protection ‘Increased Safety e’ and the type of protection ‘Increased Safety eb’ may still be used in both Zone 1 and Zone 2.

Simultaneously with the introduction of the two levels of protection, the type of protection ‘nA’ was replaced by the type of protection ‘ec’. Newly supplied explosionproof terminal and connection boxes all comply with IEC/EN 60079-7:2015.

The enclosures can be made of stainless steel (AISI 316L or 304) or stove-enamelled steel. In addition to a standard range with 16 different enclosure dimensions, stainless steel enclosures can be made to customer specifications. The covers of smaller enclosures are screwed on, while doors with square bolts are available for larger enclosures.

Further empty Ex enclosures from well-known suppliers are included in the certificate. This means that existing constructions or dimensions can be taken into consideration in mechanical engineering. Various manufacturers of empty enclosures offer the same dimensions for both the industrial and the Ex sector.

A range of polyester enclosures with 4 compatible dimensions can be joined together by means of plugged flange connections using a building block system. The external openings are fitted with flanges for accommodating cable glands. If screened cables are installed, brass flanges with suitable cable glands are available for the integration of the screening in the equipotential bonding system or for the connection to the protective earth conductor.

All the terminal boxes are prepared for wall mounting. The fixing lugs of standard stainless steel enclosures cannot only be fitted at the bottom or top, but also on the sides.

All terminals in the types of protection ‘Increased Safety e’ and ‘Intrinsic Safety i’ can be built into the terminal and connection boxes in the type of protection ‘Increased Safety e’. A clearance of 50 mm shall be maintained between non-intrinsically safe and intrinsically safe terminals. If there are mixed circuits, the non-intrinsically safe connection terminals shall be fitted with a cover in the degree of protection IP30. This cover is not required if the warning ‘DO NOT OPEN WHEN ENERGIZED’ has been affixed. However, technical solutions shall be given preference over
organizational measures.

In the case of terminal boxes with a level of protection ‘ec’, terminals with integrated fuses may also be installed.

The equipping of explosionproof terminal boxes with terminals is restricted to such a degree that, in spite of the internal dissipation, the surface temperature or the temperature of individual hot spots on the inside (conductors and terminals) satisfies the requirements for the respective temperature class stated on the type label.

The tables with the maximum number of terminals and conductors in relation to the currents for each enclosure can be found in the respective instruction manual. In the case of polyester terminal boxes, the tables for the equipping of enclosures can be found inside the enclosure cover