Wednesday, April 19, 2017

Understanding the Design Requirements of Electrical Disconnects


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, such as during set up, adjustment, cleaning and maintenance tasks, the machine should be locked out. If a machine does not have an accessible, lockable disconnect how will your workers perform lockout? Your workers are not given the tools they need to succeed.

Old disconnects allow the switch to be locked in both the ON and OFF positions. However, there is no need to ever lock a machine in the ON position. 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:

  1. Does the machine have a disconnect to remove power?
  2. Is the disconnect is good working condition?
  3. Is the disconnect labelled?
  4. Is the disconnect accessible?
  5. Is the disconnect lockable in the off position only?

Electrical disconnect lockable in ON and OFF positions:

Electrical disconnect


Electrical disconnect lockable in OFF position only:

disconnect lockable in off position only


Posted by Kristin Petaski at 8:33 PM


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