If the controls were upgraded to such an extent that the panel was replaced as an assembly then that wouldn't be a minor modification, so the remainder of the system would require review at that time with regard to CE marking as an assembly.
If this has not been done, then you can try and argue the point if it ever comes up with HSE.
You still need to comply with PUWER, and if it required local isolation this should have been implemented during the upgrade.
You need to review the hazards and risk to operatives who may un-plug the units whilst under full load, if there is enough of a risk then this must be engineered out.
PPE and procedures are the last resort, engineering solutions are available and are the specified means.
This may mean many things, including possibly bespoke units, or oversizing to allow for on load disconnection.
If the controls were upgraded to such an extent that the panel was replaced as an assembly then that wouldn't be a minor modification, so the remainder of the system would require review at that time with regard to CE marking as an assembly.
If this has not been done, then you can try and argue the point if it ever comes up with HSE.
You still need to comply with PUWER, and if it required local isolation this should have been implemented during the upgrade.
You need to review the hazards and risk to operatives who may un-plug the units whilst under full load, if there is enough of a risk then this must be engineered out.
PPE and procedures are the last resort, engineering solutions are available and are the specified means.
This may mean many things, including possibly bespoke units, or oversizing to allow for on load disconnection.
