Utility Safety Q & A Articles

Q: Recently an event occurred during a trouble job that surprised us. We had an underbuild phase down that was broken midspan. Our crew was working from an insulated bucket, and we grounded both the feeder we were working on and the one above. While our crew was beginning to crimp the splice for the repair, an energized line a few spans away came in contact with the grounded phase our lineman was in contact with. The lineman was in an insulated bucket, but he still received a shock. He was not seriously injured. Can you help us understand this?

A: The explanation is simple. Grounded circuits will still have current flowing through them if they are energized. Where there are resistances in parallel paths with the grounded circuit, there will be a voltage drop and there will be current flow through the parallel path. The current level is limited by the resistance in the path. Insulated bucket trucks are not totally isolating. To confirm that, all you have to do is look at the electrical tests performed on insulating booms. The current flow on an insulating boom is limited to a value well below the current necessary to injure a worker. In your case, there was voltage drop in the gap between the grounded, energized phase and the insulating boom that was a path to ground. Your lineman bridged that gap when he was in contact with the phase while standing in the bucket. The voltage was high enough to penetrate his skin so that current could flow. He was protected from injury by the current-limiting function of the insulating boom. We know it takes about 50 milliamps of current through a worker to rise to the level of injury. Depending on the electrical integrity of the boom and the voltage involved, there were – and this is just a guess based on boom-test protocols – perhaps 50 microamps to 1 milliamp of current that could flow on the boom. That is well below the level of injury. Electrical integrity of the boom is paramount in protecting workers. That is why it is critical to wash and maintain the boom.

Editor’s Note: This installment of “Q&A” addresses some common questions Incident Prevention receives throughout the year. Most are misunderstandings of the wording or intent of OSHA standards. From time to time iP has addressed the following scenarios – or similar ones – because they never seem to go away. In the following answers, the research or interpretation methods employed have been summarized to help readers become more familiar with interpretation and construction of the standards.

Q: Does OSHA 29 CFR 1910.269(l)(12), “Opening and closing circuits under load,” prohibit the use of non-load-break dropout fused switches or lifting of hot-line clamps to break loads? The rule reads as follows: “(i) The employer shall ensure that devices used by employees to open circuits under load conditions are designed to interrupt the current involved. (ii) The employer shall ensure that devices used by employees to close circuits under load conditions are designed to safely carry the current involved.”

A: This rule often is mischaracterized as prohibiting opening or closing under load using a non-load-break switch or a bare hot-line clamp. The rule does prohibit opening or closing a switch or hot-line clamp (“device”) under load if the employee performing the task could be injured by the act. If the employee can safely perform the act, there is no violation. To explain, there are two keys to properly interpreting this rule. One is the location of the rule; it is found in 1910.269(l), “Working on or near exposed energized parts.” The purpose of the paragraph is protection of employees, as stated in the section following the title: “This paragraph applies to work on exposed live parts, or near enough to them to expose the employee to any hazard they present.”

When OSHA reviews potential violations of the standard, they typically consider three issues: if there was a rule in place, if the employer knew about the rule and if an employee was exposed to danger by violating the rule. OSHA also will review consensus standards and best practices, as well as unadopted consensus standards, which sometimes are used in de minimis conditions and General Duty Clause violations. We know this because when we read public notice citations, we find unadopted consensus standard language used in the notice of violation without reference to the unadopted standard.

Q: I understand OSHA has made a final announcement on minimum approach distances. Can you explain the latest information?

A: On December 22, 2016, OSHA issued a memorandum to regional administrators regarding the enforcement of minimum approach distance requirements in 29 CFR 1910.269 and 1926 Subpart V (see www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=31079). The memorandum had an effective date of July 1, 2017. Readers will recall that concerns about the rising risks of transient over-voltages were the basis for the increased minimum approach distances published by OSHA in 2014. The bottom line is that OSHA has accepted an industry engineering analysis – an IEEE paper titled “Practical Approaches to Reducing Transient Overvoltages Factors for Live Work” that was delivered at IEEE’s 2016 ESMO conference – as a basis for the final guidance of the memorandum. The guidance for enforcement is simple, but it is divided for above and below 72 kV. Following are the choices spelled out in the memorandum.

New Transient Table
The IEEE paper established a new Table A with standard transient multipliers based on voltage. The employer may still calculate their own minimum approach distances utilizing an engineering analysis approved by the standard using transients published in the new Table A.

Q: We have gotten mixed advice from our colleagues at other utilities and can’t decide whether or not civil workers digging a foundation by hand in a hot substation should be required to wear arc protective clothing. They are inside the fence but in a new area approximately 20 feet from the nearest distribution structure. Where do we find the requirements or OSHA guidance?

A: That depends. Sometimes it depends on the criteria in the statutes, and sometimes it depends on compliance with company policy. Normally, following the guidelines of OSHA 29 CFR 1910.269(l)(8) – which establish the criteria for arc flash protection – excavation in a substation would not produce the type of work exposure you described that could create an arc flash. The location of the work and the type of work would not bring a worker within any distance of an energized bus or apparatus that would be a threat. If that’s the case, there would not be a requirement for arc-rated clothing for civil workers in a substation.

We are aware that there are utilities that require all workers, no matter what their craft or task is, to wear arc flash protective shirts while in a substation because it’s a company policy. But in regard to your question, it’s all about exposure. No exposure, no requirement for shirts. It is obvious that it’s not quite that simple for policymakers and risk analysts, who often are the people who make these decisions. Utilities must decide how to protect employees, protect the company and comply with the standards. That goal sometimes results in a blanket requirement as opposed to writing detailed criteria for when workers must suit up. The rules held by some utilities raise this question: If workers must wear arc-rated shirts, why don’t they have to wear arc-rated face protection? In fact, most of the inquiries we’ve made would seem to indicate the decision to require arc protective clothing in substations is more about gut response to the spirit of arc flash protection for contractors and employees than the result of arc flash analysis. Processes and knowledge are still expanding in the industry. As most would say, it doesn’t hurt for civil workers to wear arc protective shirts unless there is an unacceptable heat stress factor involved. In fact, there are some pretty lightweight pullover tees in Cat 2 that may help relieve both arc flash and heat stress.

Q: We are a contractor and were recently working in a manhole with live primary cables running through it. We were cited in an audit by a client’s safety team for not having our people in the manhole tied off to rescue lines. We had a tripod up and a winch ready for the three workers inside. What did we miss?

A: This question has come up occasionally, and it’s usually a matter of misunderstanding the OSHA regulations. The latest revision of the rule has modified the language, but following is the relevant regulation. Look for the phrases “safe work practices,” “safe rescue” and “enclosed space.”

1910.269(e)(1)
Safe work practices. The employer shall ensure the use of safe work practices for entry into, and work in, enclosed spaces and for rescue of employees from such spaces.

1910.269(e)(2)
Training. Each employee who enters an enclosed space or who serves as an attendant shall be trained in the hazards of enclosed-space entry, in enclosed-space entry procedures, and in enclosed-space rescue procedures.

1910.269(e)(3)
Rescue equipment. Employers shall provide equipment to ensure the prompt and safe rescue of employees from the enclosed space.

This rule deals with enclosed spaces, not other spaces referenced in 29 CFR 1910.269(t), “Underground electrical installations.” Enclosed spaces are not, as many think, spaces with energized cables inside. In fact, the definition of an enclosed space has no mention of energized cables. What it does have is the single criterion for an enclosed space: Under normal conditions, it does not contain a hazardous atmosphere, but it may contain a hazardous atmosphere under abnormal conditions.

Q: We have a group reviewing our personal protective grounding procedures, and they are asking if we should be grinding the galvanized coating off towers when we install the phase grounding connections. What are your thoughts?

A: In addition to your question, we also recently received another question about connecting to steel for bonding, so we’ll address both questions in this installment of the Q&A. Your question is about the effectiveness of grounding to towers, and the other question is about the effectiveness of EPZs created on steel towers. We’ll discuss the grounding question first and then move on to the EPZ question.

As to grounding effectiveness, we have two thoughts here – one simple and one that likely will raise more questions than we can resolve in these pages.

The simple thought is this: Consider grounding to the circuit static. It’s difficult to reach but doing so makes it easier to create an electrical connection. Using the system static shares current with adjacent structures and reduces current on the structure being worked. Dividing current among adjacent structures also reduces ground potential’s risks to workers at the foot of the tower. See the following Q&A regarding EPZ if you are grounding to the static.

As to connecting to the tower, grinding off the galvanized coating opens the underlying steel to corrosion and would need to be replaced after the operation. We have asked how utilities make connections and found that most use a flat clamp to a brushed plate or insulator bracket, or a C-clamp to a brushed bolt or step. Either method is a good one. Others follow one of the recommendations in IEEE 1048, “IEEE Guide for Protective Grounding of Power Lines,” 9.2.1.1 for lattice using a ground cluster. The cluster serves two purposes: providing a clamping connection and keeping the clamps close together.

Fortunately, the structure connection can be installed by hand, making the cleaning and mechanical security of the connection pretty reliable. There are several considerations to discuss that should be part of the training provided to lineworkers who make these connections.

Q: Our plant safety committee has a longtime rule requiring electrical hazard safety shoes for our electricians. We were recently told by an auditor that we have to pay for those shoes if we require employees to wear them. We found the OSHA rule requiring payment, but now we wonder if we are really required to use the shoes. Can you help us figure it out?

A: Sure, we can help. But first, please note that Incident Prevention and the consultants who have reviewed this Q&A are not criticizing a rule or recommending a rule change for any employer. What we do in these pages is explain background, intent and compliance issues for workers and employers in the workplace.

You mentioned a longtime rule that probably dates back to the early OSHA rules that required electrical hazard boots for electricians. We can’t remember exactly when, but there was a letter to administrators in the early 1990s and subsequent rule-making that changed the language on the use of electrical hazard shoes. Your auditor is right; if you require employees to wear them, you are required to pay for them because unlike regular safety shoes, the electrical hazard criterion makes the safety shoe a specialty shoe. Specialty shoes must be provided at no cost to the employee (see www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=29825).

Now let’s address the question, are the shoes required? Employers are required to perform a workplace hazard assessment and then use engineering or procedural controls to eliminate hazards. If a hazard cannot be eliminated by procedures or engineering, PPE is required. OSHA agrees throughout current literature that electrical hazard shoes are to be employed as part of a system of protection based on the hierarchy of controls. If you read the rule closely, you will see that the language is very particular. OSHA 29 CFR 1910.136(a) – edited here for clarity and space – states that the “employer shall ensure that each affected employee uses protective footwear … when the use of protective footwear will protect the affected employee from an electrical hazard, such as … electric-shock hazard, that remains after the employer takes other necessary protective measures.” Those other measures are the hierarchy first, PPE last.

Q: We are a small, distribution-only municipal utility that has been looking into human performance. We are having some trouble understanding it all and how it could benefit us. Most of the training resources are pretty expensive. Can you help us sort it out?

A: We can. Human performance management (HPM) has been around in various forms and focuses since before the 1950s. Throughout the ’50s and ’60s, it seems the focus was on companies performing functional analysis and correcting issues that created losses, thereby promoting more efficient and error-resistant operations. In the ’60s and ’70s, much of the literature on HPM seemed to surround the nuclear power industry, and indeed the introduction of HPM into the transmission/distribution side of the utility industry appears to have come through the generation side. In the ’70s, researchers began to experiment and write about more closely analyzing the knowledge and skills of the performer. It took a while to sink in, but the safety industry began to research HPM as a culture analysis and risk prevention tool. It makes sense. Human performance – in particular knowledge, skills modes, decision-making modes and performance – affects all of every enterprise whether you have an HPM program or not. Organizations are made of people. HPM has identified and categorized commonalities in types of personalities that predict how people make decisions and perform tasks. Studying human performance also can help identify safety culture issues and risk behaviors. It’s not a big or expensive step to train your workforce on problem-solving and decision-making characteristics of the human mind. Soon they will understand their own processes and the limitations of the way they naturally think, allowing them to make adjustments toward better performance. So if we can take advantage of HPM to prevent incidents, why not do it? Most organizations start small. Pick a few key people to begin training on the basics of HPM, and then look at your organization to see where the initial undertakings can do the most good. There are several experts associated with Incident Prevention who will be glad to help should you need it. Additionally, on the iP website (www.incident-prevention.com) you can find numerous HPM articles in the iP archives as well as information and training sessions from past iP Utility Safety Conferences. HPM works. We hope you will pursue it.

Q: We hear lots of opinions on whether a lineworker can lift a hot-line clamp that has a load on it. There is a rule that says disconnects must be rated for the load they are to break. We’ve been doing it forever. Are we breaking an OSHA rule or not?

A: Incident Prevention has answered this question before, but it won’t hurt to revisit it and use the opportunity to explain how OSHA analyzes a scenario to see if it’s a violation. Most objections to operating a hot-line clamp (HLC) under load are based on OSHA 29 CFR 1910.269(l)(12)(i), which states that the “employer shall ensure that devices used by employees to open circuits under load conditions are designed to interrupt the current involved.” There are some utilities that prohibit operating HLCs energized, and there’s nothing wrong with that. Our purpose at iP is not to judge an employer’s operational rules but to enlighten and educate the industry.

On its face, the rule seems to prohibit use of an HLC to break load. Anybody could also argue, then, that any operation of an HLC must be dead-break since HLC manufacturers offer no load-break value at all. However, there are several facets to analyze in this scenario. First, if a non-rated HLC cannot be lifted under load, how about a drop-out switch? We operate those thousands of times a day without injury to the employee, although sometimes an ill-advised operation does smoke a pole top. There is nothing in the rules that prohibits an employer from making an engineering-based decision establishing criteria or protocols for operating HLCs or drop-outs under certain load conditions. Primarily, the employer’s determination would be based on risk to the employee and risk to the equipment. For OSHA, the primary consideration would be risk to the employee. Just as in the working alone rule, if the device is operated by a hot stick from a position that prevented injury to the employee, there would be no violation. Second, what would be the solution in the scenario? If the solution required installing a mechanical jumper and installing a load-break switch, would such an operation add risk exposure to the crew, and would adding the switch really enhance the safety of the operation? At the very worst case, the scenario – operating the HLC under load – could be ruled a de minimis violation. De minimis is the level of violation where OSHA recognizes that a direct rule was violated, but there was no other way, or no safer way, of executing the required task, and there was no risk to the employee.

Q: What is meant by the phrase “circulating current” as it pertains to transmission towers? Does it have something to do with the fact that there is no neutral?

A: We’re glad you asked the question because it gives us an opportunity to discuss one of the basic principles of the hazard of induction. More and more trainers are teaching with a focus on principles instead of procedures, and we often overlook some of these basic definitions. The concept of circulation is associated with what happens in any interconnected electrical system. Refer to the basic definition for parallel paths: Current flows in every available path inversely proportional to the resistance of the path. That means that current flows through every path, and the path with the least resistance has the most current flowing in it. Inversely, the path with the most resistance has the least current flowing in it.

When you ground a circuit to the structure, you are making an electrical connection to the tower. Current will flow in every available path. If there is any source for current, including induction, there will be current flow. The greater part of the current will flow in the lower-resistance pathways. If the tower is well grounded, the majority of the current will flow in the tower to ground. In a distribution system, the majority of the neutral current flows in the neutral. Pole bonds to ground rods have much higher resistance and therefore lower current that usually can’t be measured by a typical clamp current meter, so some people think there is no current flowing in them. There is, and under the right conditions – such as a fault or open in the neutral – the level of current flowing in a pole bond can be deadly.

Q: We have heard that OSHA can cite an employer for violation of their own safety rules. How does that work?

A: OSHA’s charge under the Occupational Safety and Health Act is the protection of employees in the workplace. The agency’s methodology has always assumed the employer knows – or should know – the hazards associated with the work being performed in the employer’s workplace because that work is the specialty of the employer.

OSHA’s legal authority to use the employer’s own safety rules as a reason to cite the employer is found in CPL 02-00-159, the Field Operations Manual (FOM), which is published by the agency for compliance officers (see www.osha.gov/OshDoc/Directive_pdf/CPL_02-00-159.pdf). The explanation is in the FOM section about the elements required for a citation under the General Duty Clause, in particular Chapter 4, Part III, Section B, Entry 6(a). This part covers the required element of employer recognition. If there was no reasonable expectation that the employer could recognize the hazard to the employee, the employer cannot be cited for a violation. The FOM specifically states that employer awareness of a hazard “may also be demonstrated by a review of company memorandums, safety work rules that specifically identify a hazard, operations manuals, standard operating procedures, and collective bargaining agreements. In addition, prior accidents/incidents, near misses known to the employer, injury and illness reports, or workers' compensation data, may also show employer knowledge of a hazard.”

Q: Is a transmission tower leg considered a lower level? And is there an exception for hitting a lower level when someone is ascending in the bucket truck to the work area? Our concern is that the shock cord and lanyard could be long enough that the person could hit the truck if they fell out of the bucket prior to it being above 15 feet.

A: The February 2015 settlement agreement between EEI and OSHA addresses both of your questions, which, by the way, were contentious for several years until this agreement. The settlement agreement includes Exhibit B (see www.osha.gov/dsg/power_generation/SubpartV-Fall-protection.html), which explains how the new fall protection rules will be enforced or cited by OSHA. Employers should review the entire document.

Section A of Exhibit B states that no citation will be issued because a fall arrest system could permit the employee to contact a lower level while the bucket is ascending from the cradle or to the cradle position, provided that the fall protection is compliant in all other respects, the bucket is parked with brakes set and outriggers extended, and there are no other ejection hazards present.

Q: What is an employer’s affirmative defense relative to an OSHA charge and how does it work?

A: In simplified legal terms, an affirmative defense is the act of an accused party putting forth a set of alternative claims or facts. The purpose of the accused party doing this is to mitigate the claim against him, or at least the consequences of the claim, even if the facts of the claim are true. Following is an example of a fairly common scenario in which an affirmative defense is claimed by an employer. OSHA investigates an incident that resulted in an injury to an employee and finds the employer responsible. The agency subsequently issues a citation for violation of a certain rule. Most successful affirmative defenses have shown that the employer’s safety manual rule would have protected the employee if the rule had been followed; that the rule was communicated to the workforce via training; that supervisors and employees were trained to comply with the rule; that supervisors enforced the rule; and that a disciplinary program effectively remediated noncompliance. If the employer successfully puts forth that defense, he can claim the employee violated the rule outside of the control of the employer. The employer showed due diligence and cannot be held responsible for a condition over which he had no control, such as employee misconduct.

Q: I work for a small utility and am new to my safety role. Recently I have been wading through the Federal Motor Carrier Safety Regulations (FMCSR) in an attempt to understand my responsibilities with regard to testing CDL drivers. Can you briefly explain these responsibilities?

A: FMCSR 391.31 requires the employer to ensure a driver is competent by means of road testing. The FMCSR allows a valid commercial driver’s license as evidence of competency (see FMCSR 391.33). If the employer accepts the evidence of the driver’s competency, the employer does not have to road test the driver. Rule 391.33(c) allows the employer to conduct a road test if they so choose even if the driver has a current license and certificate of competency. If the employer intends for the driver to haul double or triple trailers, they are required to conduct a road test. The road test criteria are listed in FMCSR 391.31(c).

Q: I’ve been reading ASTM 855, IEEE 1048 and the National Electrical Code, and I’m a little confused by the practice of grounding through a switch. Can you help me better understand this?

A: In transmission/distribution applications, there is no issue with grounding through a switch. To explain, we always have to ask whether the issue is grounding through (in the path) a switch or grounding (by way of closing) a switch. The application may sound the same, but it depends on which standard you read. Our subject matter experts think the confusion lies in the well-known NEC rules, which require permanent installations to have a connection-free path for the ground electrode conductor at the service entrance of an electrical system. According to the code, grounds – except in some specialty connections – cannot be disconnected through operation of a switch or breaker contact. ASTM 855 is an equipment manufacturer's standard that has no application to utility practices in the field other than being used as a guide for shop construction, sizing, rating and assembly of personal protective grounds. IEEE 1048 does address the value of having the grounding switches closed when de-energizing a system for work; that ground switch is a very low-resistance path to earth at the feeder or transmission bus source that will lower fault current in an accidental or inadvertent energizing of the source. The ground switch in the station is also a path to ground that will divide and help reduce the amount of induction current on a circuit. Closing the switch can help reduce induction current at a work location, depending on how far apart the work location and the ground switch are.