In simple terms, welding the equipment into a seamless steel box could solve most 'shielding' problems. The problems that this would lead to are obvious access would be impossible, power unavailable, visibility would be zero and the equipment would rapidly overheat.

We have, therefore, to permit suitable penetrations of the shield to allow cables to pass in and out, to provide airflow and to facilitate the viewing of LED/LCD or CRT displays.

Enclosures for equipment are commonly made from steel, aluminium and, with increasing popularity due to its aesthetic design capabilities, plastic. Plastic enclosures should be coated with a metalised compound applied by vacuum deposition, painting or sputter coating. Alternatively, a lining of aluminium or copper foil can provide excellent shielding effectiveness.

In brief, the metal (or metalised) enclosure will, in most instances, require gasketing to seal mating surfaces and to provide the necessary low impedance electrical bond, attenuating vent panels for airflow and shielded windows to prevent the whole 'open' area where a display is mounted from representing an unacceptable gap in the shielding.

Inspection panels and doors can be fitted with 'soft-closure' gaskets or with contact finger strips (CFS) which also provide high shielding effectiveness with long service life and ease of closure.

Connectors for cable entry should similarly be fitted with gaskets where necessary, conductive cable glands to connect with screened cables if these are incorporated in the specification.