I'd be interested SW, in what the other contractor you mentioned, had done and whether the problems he created were, simply electrically saftey related (as in, it controlled the machinery correctly, but cuased voltages to appear on parts after they had been isolated), or controls related (as in the system had safety loop holes), or more likely.... both?
I am guessing that lives from each machines start ended up appearing at all the others even when the isolators were off, and that a machine with a stop button latched in, might be able to briefly spin up while a start was pressed?
One thing, the guy had wired it such that he disabled completely the controls on the LEV, and, in certain situations the LEV would power up immediately after restoration of voltage following a power outage.
This was a simple one, single machine, single LEV.
There was no way to shut the LEV down if the machine was running, and no labelling on the incoming isolators (3 of them) as to which one did what.
400V control across the machines.
Simple things that are fundamentally prohibited by statue law.
Don't forget, if we had a poster come on here and say that they were going to ignore requirements from BS7671 such as not fitting RCD's where required, likely they would be told that it is not allowed under BS7671, which has no real teeth in law.
Machinery wiring and controls is covered by statute law, and that does have teeth, the standards are one way to comply with that statute law, ignore them, and you must be competent, and able to justify your work is just as safe under oath.
e.g. you would never get away with using 400V control in this manner as it is not a simple machine, thus the limit on voltages then becomes 277V ac, there was no control transformer, and no control circuit over current protective devices.
