ENA TS 50-5 : ISSUE 1 1983

Designed to secure compatibility, for light current applications, between plant contacts and equipment connected to these contacts. Applies only to voltage-free contacts, i.e. those which have no voltage on them in the absence of any external connections to them Does not apply to contact circuits any part of which is situated in areas where intrinsic safety techniques have to be employed because of fire or explosion hazards, nor to switchgear tripping and control schemes.