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Topic review - Safe Return-to-Service Following a Maintenance Outage
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  Post subject:  Safe Return-to-Service Following a Maintenance Outage  Reply with quote
Best Practices for a Safe Return-to-Service Following a Maintenance Outage
Charles M. McClung, MarTek Limited
Russell R. Safreed, PE, MarTek Limited

Abstract

Returning electrical equipment to service after a planned maintenance outage creates a unique set of hazards. Facility managers are under stringent time constraints for taking the system out of service, performing necessary maintenance tasks (as well as making un-anticipated repairs) and returning the system to service by the appointed time. These common, real-world factors may create circumstances that place workers at great risk as the system is returned to service. This paper seeks to identify those initiating factors and develop logical and practical ways to lessen or eliminate risks.

It’s all a setup, with good intentions.

Most well-run, progressive-minded companies readily accept the fact that their electrical distribution system is fundamental to the operation of their facilities. Maintaining the electrical is not an option—it is a ‘must’, not merely from a continuity of operations perspective, but also from a loss prevention perspective. Delaying the restart of a manufacturing process after a planned maintenance outage because of ‘schedule creep’ or ‘scope creep’ can be costly. Extended outages caused by major equipment failure can be devastating.

As important as these economic factors are, the prevention of a life-altering injury or death trumps all economic incentives. However, few would disagree that protecting people is also another form of loss prevention. Aside from the moral responsibility that is incumbent on employers to protect their workers, the failure to adequately protect people will likely result in significant economic losses in the form of OSHA fines, medical payments, higher worker’s compensation premiums and litigation.

Electrical maintenance outages are high-stress for everyone concerned. The Plant Manager just wants it to be over so operations may be returned to normal as soon as possible. The Electrical Distribution Engineer wants the greatest amount of work possible to be done in the allotted time to help ensure he never has to answer to the Plant Manager for an unplanned outage. The Maintenance Crew wants to be thorough and do a good job, but they also know the criteria for deeming the job ‘well done’—returning the system to operation on-time and with just enough ‘bad news’ about the condition of the equipment to justify the expense of the outage, but with not so much ‘bad news’ that a re-start is delayed or that significant repairs would be necessary.

All of these real-world pressures and sometimes competing objectives can produce a high-risk condition when the time comes to re-energize the electrical system following a planned maintenance outage.

Three major categories of risk-creating scenarios will now be explored.

Equipment deficiencies:

Although the objective of the maintenance outage is to extend the life of the equipment and promote safe and reliable operation, the opposite is sometimes the outcome. Humans perform maintenance tasks. Humans make mistakes. Even the best technicians get distracted and fatigued.

Recently, a facility owned by a Fortune 500 company experienced a serious arc-blast event because a ‘blown current limiter’ sensing wire was left disconnected on one end. When the breaker was returned to service, the lead contacted a grounded surface and an arc-blast ensued.

Not all equipment deficiencies in this realm are caused by careless acts. Particularly in older facilities, experience has shown that older medium voltage cables frequently fail upon re-energization after being de-energized for several hours. This can be caused by a number of mechanisms. Water absorption through insulation ‘treeing’ and thermal cycling are the perhaps the most common.

Tools left behind:

As stated previously, humans perform maintenance tasks, and humans make mistakes. Leaving a tool behind in an area where it could initiate a fault is not too uncommon. Even as some of humanity’s brightest and most educated and well-trained individuals—surgeons sometimes make similar mistakes.

In electrical equipment, a left-behind tool may not immediately present a problem. It may take the jarring of a breaker operation to dislodge the tool from its resting place into a position where it creates a fault.

Keep in mind, it’s not only good operating practice to inspect for tools and such before re-energizing—it’s the law!

OSHA 1910.333(b)(2)(v)(A)
A qualified person shall conduct tests and visual inspections, as necessary, to verify that all tools, electrical jumpers, shorts, grounds, and other such devices have been removed, so that the circuits and equipment can be safely energized.

Still, in spite of the best efforts, mistakes occur.

Human error/poor judgment:

The ‘tyranny-of-the-urgent’ is ever-present—the rush to complete maintenance testing, the evaluation of test results on-the-fly, the decision of which maintenance activities to forego in order to meet the appointed time for re-energizing, the temptation to cut corners. The list goes on and on.
In the end, one is left wondering. Was some key piece of information misinterpreted? Was the insulation resistance too low to re-energize? Can the equipment be safely returned to service?

Mitigations

A well-conceived, written return-to-service plan is essential. A person who is familiar with the facility and knowledgeable of electrical systems and the associated hazards, must perform such planning ahead of time. The plan should include a detailed sequence of operations for energizing the system. Responsibilities should be clearly assigned and understood. Communication is key.

An often-overlooked component of a return-to-service plan is contingency planning. Plans should include: procurement of repair/replacement components; supplemental skilled manpower availability should a need arise; inclement weather contingencies; and temporary equipment availability, such as compressors, pumps and generators.

Utilize proper safety-related work practices. Hazards such as ‘incident energy’ must be understood and quantified. Foster a mindset driven by a culture that does not tolerate risk taking. Specify and use the appropriate PPE. In some cases, PPE may not be enough. Portable remote controls are an alternative—they mitigate not only the thermal effects of an arc-blast, but also the hazards of shrapnel and flying debris hazards.

Utilize safeguards built into the facility—‘maintenance switches’ that temporarily lower breaker settings, or the use of permanently installed remote controls.

When it comes to operating discipline—if possible, avoid or minimize the time of closed-transition switching (temporarily paralleling two sources for the purpose of supplying a load from a different source, without interrupting the load in the process). This condition may result in switchgear that subjected to a fault current that exceeds the switchgear’s ability to withstand or interrupt.
The Law sums it up well… INSPECT for foreign objects and STAY CLEAR when reenergizing.

1910.333(b)(2)(v)
“Reenergizing equipment.” These requirements shall be met, in the order given, before circuits or equipment are reenergized, even temporarily.
1910.333(b)(2)(v)(A)
A qualified person shall conduct tests and visual inspections, as necessary, to verify that all tools, electrical jumpers, shorts, grounds, and other such devices have been removed, so that the circuits and equipment can be safely energized.
1910.333(b)(2)(v)(B)
Employees exposed to the hazards associated with reenergizing the circuit or equipment shall be warned to stay clear of circuits and equipment.


Remote operators are an excellent example of an effective and economical means to protect workers by giving them a method to ‘stay clear.’

Summary

Returning to electrical equipment to service is obviously a hazardous task with the risks increased due to the pressures of returning the equipment to service. Equipment deficiencies, tools that may have been left behind, human error, and poor judgment all increase the probably of an incident. Understanding these increased risk factors and having a good mitigation plan will go along way towards reducing these risks.

About the authors

Charles Mark McClung began as an electrician apprentice with Union Carbide Corporation in 1974. After working twelve-years as an electrician he held various management and technical positions in plant maintenance and utility distribution. After a 35-year career, he took early retirement to devote his full attention to the development, manufacturing and marketing of electrical safety devices.

Russell R. Safreed, III earned a BSEE degree in 1987 from West Virginia Institute of Technology. He has worked in various engineering roles for Fortune 500 companies ranging from power distribution engineer to power system design engineer to electrical construction management. Today, he is a principal at MarTek Limited and focuses on design and development of remote switching tools for NFPA 70E compliance.
Post Posted: Mon Apr 20, 2015 7:53 am

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