Plug-and-socket connectors

Requirements are given in EN 50014 as well as in IEC 60079-0 General requirements, covering all types of protection. Plugs and sockets shall be mechanically or electrically (or otherwise) interlocked to avoid disconnection when energized, or shall be fixed together by special fasteners and additionally be marked with a warning label DO NOT SEPARATE WHEN 

ENERGIZED. (In Germany, plugs and sockets with an interlock are known as Steckvorrichtungen, without an interlock as Steckverbinder. ) 

In the low power range (not exceeding 10 A and 250 V AC or 60 V DC) there are less stringent requirements. 

The standards for flameproof enclosure - d EN 50018 and IEC 60079-1 give additional requirements for plugs and sockets not fixed together by means of special fasteners  

An example of a flameproof plug and socket is given in Figs 6.140 and 6.141. The socket - in the non-operating mode - is covered by a rotating shutter  

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Business machinery applications include keys for keyboards, typewriter ribbon guides, plug and socket connectors and optical cable sheathing. 

The main field of application of oil immersion - o is the explosion protection of Group II transformers in the high power range (up to some 1000 kVA). The terminal compartments often comply with increased safety -e or plug and socket connectors (in e ) are used in the high voltage range (see Section 6.7). 

Figure 6.10 shows a typical example for a q-apparatus. It is a power supply for intrinsically safe electric circuits to be installed in zone 1 (and zone 2). The power input (at 24 V AC/DC level) is fed via flameproof plug-and-socket connectors to the apparatus. So, the power supply can be replaced under load without conflicting with the requirements of explosion protection. 

Figure 6.18 Flameproof (EEx dl) plug-and-socket connectors for outgoing power lines (1140 V 3 AC, up to 450A) fitted at the sidewall of an EEx p I switchboard (this is shown in Fig. 6.19).

Plug-and-socket connectors complying with increased safety - e - (see Section 6.7.2) or with flameproof enclosure - d - (see Section 6.8.10) provide a simple installation and maintenance of pressurized apparatus, especially in coal mines where frequent and rapid changes of place are required. Figure 6.18 shows flameproof plug-and-socket connectors fitted at the sidewall of a Group I pressurized switchboard. 

Figure 6.54 High voltage plug-and-socket connector (single pole)...

Figure 6.81 Flameproof plug-and-socket connectors ( cable couplers ), fitted into a flameproof enclosure (EEx dl equipment for coal mines).

Plug-and-socket connectors, cable couplers, see Fig. 6.81. These parts are inserted into an opening of the flameproof enclosure and act as a flameproof seal. This also applies to the unplugged state of plug and socket. Such means are favoured where apparatus is frequently removed, e.g. in coal mines (Group I application). 

At the low voltage side, plug-and-socket connectors are applied for the outgoing lines. So, no low voltage terminal compartments are fitted. 

Figure 6.141 Plug-and-socket connector, functional principle.

Not all of the apparatus inserted in an intrinsically safe circuit need to have a certificate. This is based on the fact that, e.g., a terminal, a plug-and-socket connector or even a contact sparking in normal operation will not cause a risk if the electrical circuit is intrinsically safe. 

EEx e-terminals EEx i - plug-and-socket connectors 1 X EEx d plug-and-socket connector 1 X EEx i plug-and-socket connector 912-... 

MAJOR APPLICATIONS High-temperature applications, automobile parts (e.g., radiator, ventilation, and fuel supply systems), electronics housings, plug and socket connectors, printed circuit boards, tennis rackets, golf clubs. 

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