Relays shall have indication of status (on/off) by signal lights (LED) or by a mechanical arrangement. Relays shall have a test button. The relays shall be connected via a standard 11-pole circular socket mounted on DIN- rails. 

Pilot and indication lamps shall be of the LED type and provided with a common lamp test facility. 

## 8.7.4 Access 

All apparatus, equipment and components within assemblies must be so arranged that they can easily be identified and worked on, and, as necessary, removed for repair and maintenance. Sensitive equipment must not be installed on covers, doors or hinged assemblies. It is a requirement of this specification that any piece of equipment shall be removable without disturbance to any other piece of equipment. 

## 8.7.5 Internal wiring 

All wiring within assemblies must be supported in trunkings appropriate during construction. Component terminals must never take the weight of wires. All supports for wiring must be either screwed or stud welded. Adhesive type supports are expressly forbidden. 

All wires shall have stranded copper conductors. The minimum conductor size shall be 0,75 mm 2 (except 

original connector cable). The maximum size for door mounted equipment shall be 2.5 mm$^{2}$. 

Wiring at different voltages and AC and DC must be segregated in accordance with IEC 60364. 

Wiring shall not be less than 300/500 volt grade with an insulation temperature withstand of not less than 70° C. Wiring is to be sized according to the prospective fault current level and duration in reference to current rating. Joints between components in wiring will not be permitted. 

## 8.7.6 Terminations 

All terminals and terminal blocks must have each termination numbered. Connectors at all panels shall be numbered. Power supply terminals are to be identified with colours and/or numbers corresponding to phase designations. Depending on the type of terminal, cable lugs shall be attached to wires or cores; however, the use of "C" or "Jaw" type lugs is expressly forbidden. 

## 8.7.7 Earthing 

All normal non-current carrying metal work of an assembly must be bonded to the earth connection point within the enclosure. All doors, covers or assemblies must be permanently connected. All earth conductors must be single core multiple stranded and PVC insulated for mechanical protection, coloured green/yellow spiral striped. 

## 8.7.8 Transient and surge protection equipment 

Transient and surge protection equipment shall be connected to the main incoming power supply cables and medium voltage power consumers like motors and transformers, if any. The equipment shall be placed in its own section of the assembly and located as near as possible to the consumer. Each phases and the neutral shall be provided with overvoltage/transient protection devices. Status (available/defect) of the transient protection equipment is to be signalled to the PLC. 

Requirements for transient protection equipment are listed in a separate chapter. 

It will be used for type 1 power inlet in Main distribution boards, type 2C in MCC boards and type 3D power inlets for PLC board. Suitable surge arrester will be used in outdoor equipment boards accordingly with usage objective. 

