Techniques for cable entries

In general, there are four methods for cable entries in pressurized apparatus  

In the case of air as a protective gas, the somewhat increased air pressure inside the e-terminal compartment causes a shift to the safe side increased gas pressure (p) reduces partial discharge strength SPD (if any) in a given electric field strength according to  

Spoo = partial discharge strength at 1.0 105Pa (=1.0 bar absolute pressure) 

In many cases, (3 has been found with some 10° bar 1 [20]. Atypical example for partial discharges in air and their pressure dependence is given in Fig. 6.17. 

This may indicate that small overpressures inside the d compartment, in line with these limitations, will not adversely affect this type of protection. 

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Figure 6.80 Techniques for cable entries into a flameproof enclosure (left to right) ...

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