When we inspect equipment, one of the things we always check is the presence and state of the electrical disconnect. You may ask why this is important, after all, it is just a switch. However, a proper disconnect allows your workers to follow safety procedures. Any time a worker must enter a hazard zone outside of normal operation, such as during set up, adjustment, cleaning and maintenance tasks, the machine shall be locked out. If a machine does not have an accessible, lockable isolation point how will your workers perform lockout? Your workers are not given the tools they need to work safely.
Control switches do not isolate the flow of energy, they only interrupt it. It is crucial to ensure you are using a device that actually isolates the energy by maintaining sufficient physical space between contactors, eliminating the chance for a fused or arced contact and accidental start up.
Old disconnects allow the switch to be locked in both the ON and OFF positions. Having this functionality opens up the possibility for someone to make a mistake. We have seen it happen before, an experienced worker accidentally locks the machine ON instead of OFF. That is why it is required to have disconnects that are lockable in the OFF position only.
Take a walk through your shop and look for the following on each machine: