Hello, I have been carrying out an EICR on an industrial installation and it was brought to my attention a control circuit at a machine has been supplied from a 230V Isolation transformer. The transformer has no Neutral to Earth bond on the secondary side, the controls enclosures are metal clad with all exposed metal parts earth bonded back to the main earthing system on the primary side. There are several simultaneous conducting parts adjacent i.e. sockets, FSU, wall heater, structural steel support to building all adjacent to the console and it is conceivable that all conducting parts could easily be reached so a non-conducting location is not possible.
My understanding of control circuits is that the common 0V connection must be grounded for several reasons, single fault detection and to ensure correct operation of contactors, relays, coils etc in the event of a single fault so as to mitigate maloperation.
Can anyone provide any advice/feedback please.
Cheers.
