In the past couple of years I have come across these lockout devices for light switches.  I even witnessed an OSHA Outreach Trainer using a picture of a similar device in a 10-hr OSHA course during his LOTO presentation.  Now I know that a light switch can be wired a special way that could make it an isolation device; but I would bet that 99.99% of light switches are NOT wired such that when they are in the OFF position they are a POSITIVE MEANS of energy isolation.  Light Switches are CONTROL DEVICES and OSHA's definition of an "Energy Isolating Device" states it is a mechanical device that physically prevents the transmission or release of energy, including but not limited to the following: A manually operated electrical circuit breaker; a disconnect switch; a manually operated switch by which the conductors of a circuit can be disconnected from all ungrounded supply conductors, and, in addition, no pole can be operated independently; a line valve; a block; and any similar device used to block or isolate energy. The definition also states the following...Push buttons, selector switches and other control circuit type devices are not energy isolating devices.  I am claiming that light switches are "control circuit type devices".  To me the use of these devices is a clear cut violation of 1910.147.  The authorized employee should use a breaker or disconnect to do work on the light.  Turning the light switch off and hanging one of the devices and your LOTO lock on the device then cutting the wires to the ballast will result in an electrofying experience for the worker!!  What do you think?  Vote in the poll below and let me know.  If you disagree, PLEASE post your position and why you feel they are legal in the comments section below.