Lesson Learned Statement:Two "universal" locking devices with locks attached were placed on single pole circuit breakers, one directly above another in a weather-tight outside temporary electrical service panel. The top lock overlaid the bottom lock. When the panel door was closed, it pressed on the locks, pushing the top lock to the side and causing it to act as a lever pulling the top circuit break closed.The investigation identified that some circuit breakers require specific types of locking devices to be effectively locked out of service. Circuit breaker locking devices labeled as being "universal" are not effective on all brands and models of circuit breakers. Discussion:On September 5, 2003, while preparing to replace a failed GFCI receptacle in the T-17 load center at the 233-S facility, two 110-volt single-pole circuit breakers were locked and tagged in the open position. After the two locks and tags were installed and verified, the door on the load center was carefully lowered to the closed position. The worker closing the door felt no unusual resistance and no one in the vicinity heard any unusual noises.During the "Safe-Condition Check" on the receptacle to be replaced, the electrician discovered voltage. Upon raising (opening) the T-17 load center door, he found the locking device on the top breaker was barely attached to the breaker and the breaker switch had moved sufficiently to energize the receptacle. There were no injuries or equipment damage and no work had occurred with the receptacle energized. Analysis:Investigation revealed that the two locking devices were installed one above the other. When the electrical panel cover was closed, it contacted the upper lock, causing it to lever against the lower lock, pry the locking device partially off of the breaker, and close the breaker.During the review of this incident, facility personnel discovered that the lockout device manufacturer's product data sheet stated that the "Universal Single Pole Lockout" works with all single pole circuit breakers "except Square D QO style and some Federal Pacific breakers." Recommended Actions:Exercise extreme care when installing electrical panel covers, especially on applications involving multiple locks on electrical panels.Consult manufacturer's product data sheets to ensure compatibility of lock out device components to be used with the manufacturer's equipment. Manufacturers of electrical components may provide restrictions on certain lockout devices. Many universal lockout devices specifically exclude Square D QO and Federal Pacific breakers. Some circuit breaker manufacturers make lockout devices specifically for their circuit breakers. Square D, for example, makes lockout devices for their Type QO circuit breakers that are reportedly very effective. A circuit breaker manufacturer’s lockout device should be the first choice, if available. See the appropriate manufacturer's website for compatible lockout devices for specific breakers. The Hanford Workplace Electrical Safety Board (HWESB) recommends using circuit breaker lockout devices with a thumbscrew clamping mechanism for best results. Originator:Fluor Hanford, Inc. Submitted by Jeff Riddelle (509) 372-1684 and Don White (509) 373-9144.Validator:John BickfordContact:Project Hanford Lessons Learned Coordinator; (509) 373-7664Name Of Authorized Derivative Classifier:Not requiredName Of Reviewing Official:John BickfordPriority Descriptor:Blue / InformationKeywords:breaker, lockout, tagoutReferences:Occurrence Report RL--PHMC-CENTPLAT-2003-0026Operating Experience Summary 2003-10, Article 5, Electrical Circuit Breaker Locking Device Problems Operating Experience Summary 2003-06, Article 4, Lockout/Tagout Violations and Lessons Learned Lessons Learned 2002-RL-HNF-0032, Selection of Lockout Devices, June 14, 2002 Lessons Learned 1999-ALO-WID-00071, Inadequate Breaker Locking Devices, November 2, 1999 Lessons Learned L-2003-OR-BJCETTP-0803, Lockout Device on Circuit Breaker Falls, August 22, 2003 Information in this report is accurate to the best of our knowledge. As means of measuring the effectiveness of this report please use the "Comment" link at the bottom of this page to notify the Lessons Learned Web Site Administrator of any action taken as a result of this report or of any technical inaccuracies you find. Your feedback is important and appreciated. DOE Function / Work Categories:Conduct of Operations - Lock and TagMaintenance - Electrical ISM Category:Develop / Implement ControlsHazard:Electrical / NEC
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