Electrical Isolation for Hazardous Area Equipments to IEC 60079

[123MB]

Hi All,

Following on from the following thread:

thread238-386475

Is it your interpretation that the isolation of all conductors, including the neutral, applies to conductors of PELV instrument loops - 24V, earthed 0V, and signal wires?

What about earth conductors? should they also be isolated? It is concievable that a remote earth fault could cause a potential difference at the end of any conductor, including earth, that has been lifted from its termination i.e. to replace an instruemnt

Thanks

 

[7anoter4]

Protective extra-low voltages systems (PELV) shall be in accordance with 414 of IEC 60364-4-41. Protective extra low voltage (PELV) system circuits are earthed.
As it is known BS7671 it is based on IEC. For PELV reference Regulation 414 is the same as IEC 60364-4-41 Rule 414. Regulation 412 and 416 state the cable insulation minimum voltage it has be 300/500 V[412.2.4.1]. Neutral is considered as live.
Regulation 543.2.1:
A protective conductor may consist of one or more of the following:
IV) A fixed bare or insulated conductor. Then if it is fixed may be bared. If it is insulated, in my opinion, it has to be as per Regulation 412.