It is widely known that OSHA permits a worker who is in EXCLUSIVE CONTROL of an electrical plug when electrical is the ONLY energy source to perform their servicing and maintenance without applying a lockout device on the plug. This is permitted by
1910.147(a)(2)(iii)(A) Work on cord and plug connected electric equipment for which exposure to the hazards of unexpected energization or start up of the equipment is controlled by the unplugging of the equipment from the energy source and by the plug being under the exclusive control of the employee performing the servicing or maintenance.
However, it is common to see LOTO programs apply this exception to other forms of energy, most notably air hoses and hydraulic hoses. But there is a HUGE difference between unplugging an electrically powered piece of equipment vs. unplugging a piece of equipment under pneumatic (e.g., compressed air) power.
OSHA does NOT permit this exception to be applied to any other power source other than electrical, and here’s why.
When the plug is removed, a piece of equipment plugged into an electrical outlet will return to its Zero Energy State (ZES). Of course, if the equipment has a means to “store” an electrical charge that could be a hazard to employees, then common sense tells us this exception will NOT apply to this piece of equipment! But 99% of the cord and plug equipment returns to its ZES when it is unplugged. This is NOT the case when the equipment is powered by compressed air. Simply unplugging the equipment’s air hose will NOT return the equipment to its ZES. Yes, some sophisticated air connections will bleed off the residual pressure when the air hose is disconnected; however, those traditional connections using the “quick connect” coupling will NOT bleed off the “stored energy,” and with the “stored energy” still in the equipment we have not achieved a SAFE STATE (e.g., ZES) for servicing and maintenance. And the same scenario would apply to hydraulic power.
It should also be pointed out that if the worker is going to do work on the equipment that does NOT include electrical work, this exception will apply. Suppose the worker is a “qualified electrical worker,” and he/she will be working on the electrical associated with the machine/equipment. In that case, 1910.147 is NOT the standard for this work; therefore, this “cord and plug” exception would NOT apply to the “qualified electrical worker”. This “qualified electrical worker” would fall under 1910.333(b), which contains NO SUCH exemption!
Here is an OSHA LOI regarding this LOTO exception.