PowerLOK™ circuit breaker plug lockout device includes many innovative features to provide a versatile, easy to use lockout/tag out device. This device can be applied to single or multi-pole circuit breakers (such as 120/277 V breakers) to prevent the breaker from being turned back on for safe performance of maintenance or service in accordance with lockout/tag out procedures. Individual plugs in a wide range of sizes can be locked out to prevent energization. Accommodates padlocks with shackle lengths of 1.50 inch (38.1 mm) or greater and plugs with a hole in a blade. Constructed of rugged polycarbonate providing strength, durability, added security and corrosion resistance.