Copper wires (or any other electrically conductive object) cannot transit a Faraday cage directly, if they do then there will be a sever loss of attenuation (shield performance).
The answer is to use capacitive filter arrangements employing capacitors from phase-to-phase (X capacitors) and Capacitors from phase or neutral to earth (Y capacitors) there are also in line ‘bulkhead feed through capacitors).
Often ‘common mode chokes’ are also used.
There are different types of power and data, the following are the most common
- Single phase power filter 32A 230v (can be higher current)
- Three phase power filters, 32A/line is common but can be higher current
- High Current DC
- 400Hz and 800Hz
- Low pass data filters