Protective, Instrumentation and Telecommunication Earth

Protective earth

Field equipment shall be connected to the PE system through the cable. The braid armour shall be
the earth conductor and it shall be electrically continuous from the field to the central equipment PE
bar.

For power cables where the braid armour does not have sufficient cross section, the equipment shall
be earthed through a separate earthing conductor in the cable.

Equipment supplied by single core cables shall be connected to PE by a separate earthcable. The
separate earth cable shall run alongside the power cables to form a “cable system” and be terminated
to the field equipment earth terminal as well as feeding end earth bar/terminal.

The copper braid of the single core cables shall be earthed at one end, isolated in the other end.
Where hazardous areas are involved, the copper braid shall be earthed in the hazardous area.

Ex d electrical equipment with direct entry, shall be connected to the PE system by a separate earth
conductor in the cable.

The PE earth cables or braids armour of cables, connected to a switchgear, cabinet, equipment etc.,
to be connected to a PE earth bar as close as possible to the cable entry of the switchgear, cabinet,
equipment.

The PE earth bar to be easy accessible.

Instrumentation and telecommunication earth

The IE shall be the earth reference for non intrinsically safe, intrinsically safe instrumentation and
telecommunication 0 volt references etc.

The IE screen shall be left floating in the field end. It shall be electrically continuous from the field
equipment and be connected to IE bar in the central cabinet.

The screen shall be connected to one IE bar only for signal cables between two control cabinets.

Bonding

Exposed conductive parts located in hazardous- and mechanical ventilated areas shall be bonded to
the main structure.

Bonding shall be provided between the platform structure and all preassemblies, modules and decks
that are not welded or bolted together.

Separate bonding shall only be applied for equipment, which is isolated from main structure.

Enclosures of high voltage equipment located in hazardous areas shall be connected to PE and
bonded to the main structure.

Earth bar

Earth bars shall be fabricated from copper and provided to suit number and size of connections.

PE bars shall be connected to the nearest convenient main structure point through an insulated earth
conductor or through the supply/feeder cable.

IE Bars shall be isolated from the enclosure and connected to the nearest convenient main structure
point through an insulated earth conductor.

2 Likes