Utility Safety Grounding Articles

Q: Whenever we see graphics for single-point grounding, it’s always a cluster, a connection to the neutral, a connection to a phase and a chain connecting to the other two phases. But when we check with other utilities or consultants, we see all kinds of arrangements, such as bracket grounds with a single point or two sets of single-point grounds bracketing the workspace. Where do we find the definitive arrangement, and why are there so many variations?

A: Under OSHA, the employer is solely responsible for determining how they will meet the requirements of 29 CFR 1910.269(n)(3), “Equipotential zone,” which requires that grounding of de-energized phases be installed in an arrangement that prevents employees from being exposed to differences in electrical potential. In addition to 1910.269(n)(3), there also is Appendix C to 1910.269, “Protection From Hazardous Differences in Electric Potential,” as well as IEEE 1048-2016, “IEEE Guide for Protective Grounding of Power Lines,” a consensus standard that may be considered the authoritative best practice. IEEE 1048 is filled with detailed electrical data – from modeling to application – to explain how to create equipotential protection and effective tripping of grounded circuits that may inadvertently be energized.

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.

When the earliest linemen first began to ground lines for worker protection, they attached a small chain – known as a ground chain – to the conductors, with the end dropped to the ground. When I began to work on a line crew, I’m sad to say that my grounding practices weren’t much better than those used in the early days. I wish someone had better explained to me then the situations that could arise, the ways grounding could protect me and the best methods to accomplish it. So, in an effort to help out other lineworkers in the electric utility industry, I want to share in the following pages some of the important aspects of grounding that I’ve learned throughout my career.

Worker Protection
Ever since enforcement of 29 CFR 1910.269 began in 1994, OSHA has required grounding practices that will protect employees in the event that the line or equipment on which they are working becomes re-energized. The equipotential zone, or EPZ, is made to do just that.

If you read paragraph 1910.269(n)(3), the preamble discussion and Appendix C to 1910.269, titled “Protection From Hazardous Differences in Electric Potential,” OSHA’s intent seems clear. To summarize, install temporary grounds and bonds at the worksite in such a manner that keeps the worksite at the same potential and prevents harm to workers even if the line is accidentally re-energized or exposed to induced voltages. You can follow Appendix C as a one-size-fits-all approach or perform your own engineering analysis to create procedures. But keep in mind that if you create your own procedures, you must be able to demonstrate they will protect your workers.

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.

Football season is here, and hunting season is right around the corner. That means it’s also outage season for the electric power industry.

Planned outages allow utilities to take equipment out of service for maintenance, replacement or new construction. The timing is dictated by the utility owners and the regional transmission organizations that oversee the power grid. Planned outages can last from 15 minutes to months, and they can be continuous or intermittent. Most occur late in the year because loads are lower than during the peak summer and winter months. In addition, utilities need to use up their capital budgets for the year.

The height of outage season is between Thanksgiving in the U.S. and Christmas. With the rush to perform outages as quickly as possible, they often entail 12- to 16-hour workdays and seven-day workweeks for crews. Given the pace and intensity, along with the weather conditions, the potential for injuries is significant. To combat these risks, following are a number of best practices that can be used in your organization to help keep crews safe during outage season.

Site-Specific Safety Plan
Safely performing an outage begins with the crew developing a comprehensive, site-specific safety plan that – at a minimum – addresses manpower, equipment, logistics, training and emergency response. Because planning for most outages takes months, there’s plenty of time to thoroughly address safety.

Manpower
When developing the safety plan, establish how many workers will be needed to perform tasks safely and efficiently. In particular, consider work hours, because expecting workers to put in too many hours increases the risk of something going wrong on the job. Do you need 10 employees to perform 16-hour shifts seven days a week, or is it more prudent to ask 20 employees to work 10-hour shifts for five days?

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.

A few years ago I came upon a crew using 6-inch chocks to hold back a 38-ton crane truck. I told the crew I was happy that they were making an effort at compliance, but I had to ask them, “Why do we place chocks under a truck’s wheels? Is it to comply with our safety rules or to keep the crane from running away?” It was obvious to me that the short chocks would not hold the crane. The driver proved my assumption true a few minutes later. From the cab, with the transmission in neutral, he released the parking brake. The crane easily bounced over the chocks and, unfortunately, hit my pickup truck.

Sometimes I ask similar questions about grounds installed during stringing. That’s because it seems we do not pay as much attention to the value of grounding as we do to the perceived value of an act of compliance. Grounding during stringing plays a very important role in protecting workers; however, that’s only the case if we know why we are grounding and then install grounding so it does what we want it to do.

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.

Q: Is equipotential grounding now a personal protective grounding method required by OSHA?

A: The answer is yes, even though OSHA doesn’t specifically say so in terms we easily understand. The terminology isn't OSHA's fault. As an industry, we adopt certain familiar ways of describing or discussing things and simply don't recognize what OSHA is trying to communicate unless we do some diligent research. In 29 CFR 1910.269(n)(3), OSHA requires arrangement of grounds to protect employees without using the word “equipotential.” The title of the rule, however, is “Equipotential zone.”

The full text of 1910.269(n)(3) states, “Temporary protective grounds shall be placed at such locations and arranged in such a manner that the employer can demonstrate will prevent each employee from being exposed to hazardous differences in electric potential.” By definition, that is equipotential grounding.

In the last 10 years I have consulted on dozens of induction incidents, eight of which resulted in fatalities. There were commonalities in each one. Just about every Incident Prevention reader will agree that one of the topics that receives the most attention across the power industry – in writing, training and conversation – is personal protective grounding (PPG). Not a week goes by that I don't email or talk to someone about PPG and, in particular, about dealing with induction.

At iP we discuss and share information as well as news about incidents involving induction, and yes, they do occur at an alarming rate. I can't point to any empirical evidence, but my colleagues and I think we, as an industry, are the reason for the confusion over PPG issues. We have been slow to evolve from grounding for the purpose of stabilizing electrical systems and protecting equipment, to grounding for the protection of workers. Even the language of the OSHA standard, to some, seems vague, contradictory or too technical. The ANSI standards establish sound procedures for protective arrangements, but they are not training resources for craft workers. Now, as infrastructure loads and system voltages continue to increase, there are corresponding hazards that were not even discussed just a generation ago. Those hazards are resulting in incidents and, worse, preventable incidents that risk the lives of power-line workers.

In recent months Incident Prevention has received several questions about underground (UD) padmount transformers, so in this installment of “Voice of Experience,” I’d like to take the time to cover the general aspects of these types of transformers.

To begin, there are a few different types of single-phase and three-phase UD padmounts: live front with exposed live primary parts, 600-amp bolt-on elbows and loop feed with bushings and elbows. All of these transformers are available in several voltage ranges.

The proper PPE must be worn when an employee is opening, entering and working on energized transformers. This includes a rated hard hat, eye and face protection, rubber gloves, heavy leather boots and arc-rated FR clothing. Additionally, all PPE must be worn by any employee exposed to energized equipment and cables until the transformer has been de-energized and checked for the absence of voltage, and all exposed parts have been properly grounded.

Q: Are there any changes to steel-toe boot requirements for lineworkers in the recently revised OSHA 1910.269 standard?

A: OSHA still leaves it to employers to decide whether hard-toe or protective footwear is required. As with all other PPE, the decision should be made based on risks and history. Wearing safety footwear is not required by the PPE rule. However, what is required in OSHA 29 CFR 1910.136, “Foot protection,” is a mandatory assessment of the work environment. The rule states that the employer “shall ensure that each affected employee uses protective footwear when working in areas where there is a danger of foot injuries due to falling or rolling objects, or objects piercing the sole, or when the use of protective footwear will protect the affected employee from an electrical hazard, such as a static-discharge or electric-shock hazard, that remains after the employer takes other necessary protective measures.”

Q: In regard to work boots and arc flash protection, what does OSHA mean by “heavy-duty work shoes or boots” in 29 CFR 1910.269(l)(8)(v)(B)? Are boots made of synthetic material acceptable if they are work boots?

A: As with all OSHA rules, it is up to the employer to understand the risks and the necessary protections. In many cases the consensus standards give guidance that can be used to satisfy the OSHA standard. Even though NFPA 70E exempts utilities, OSHA has clearly used the NFPA as a source of material to assist utility employers in protecting employees, and the clothing standards in 70E may be a good place to start. NFPA 70E is not an adopted standard, but as OSHA stated in an October 18, 2006, letter to Michael C. Botts (see www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=interpretations&p_id=25540), “A national consensus standard … can sometimes be relevant to a general duty clause citation in the sense that the consensus standard may be used as evidence of hazard recognition and the availability of feasible means of abatement.” In Table (C)(10), NFPA 70E requires leather boots as needed.

Stringing wire in any environment can quickly go wrong. Dropped conductors can wreak havoc if precautions are not taken. In an energized environment, the result of losing control or dropping conductors has a greatly magnified risk.

Guard structures are the first type of protection conventionally used to prevent contact with energized lines. Ideally, guard structures are positioned so that whether it’s the unexpected loss of stringing tension or something as major as a dropped conductor, the conductor being pulled will not make contact with the energized lines. There are other requirements, too, one being non-automatic setting of breakers for the lines being crossed if it is not possible to de-energize and ground them.

A few years ago at a company I worked for, an experienced, highly trained professional lineman, thinking he was lifting a truck ground, inadvertently lifted the ground rod connection for a transmission circuit bracket ground. Induction current instantly killed him as though he had made contact with an energized phase. The genesis of the incident was largely a lack of attention to details as everyone seemed to be aware of the risks and understood the purpose and need for the grounding that was installed.

National equipment standards constantly evolve due to near misses and incidents that occur in the field. This evolution results in electric utilities adopting different work methods and procedures, equipment, education and training to keep utility workers and the public safe as every electric utility company builds and maintains the national electric grid.

I define safety as identifying and managing hazards to prevent incidents. That is accomplished using a broad array of tools and rules for the employer and workforce. Good safety professionals and trainers have to go beyond the OSHA and MSHA regulatory text to completely understand the rules. That is where preambles to the standards, interpretations, CPLs and consensus standards are needed.

I suspect that in the past 20 years the utility industry has grounded more circuits for the protection of employees than were ever grounded in the first 115 years of utility operations. Judging from the number of serious incidents and hazardous conditions created by temporarily grounding systems, it seems that we may not have understood all of the issues. It's almost intuitive; grounding makes the work safer, but for whom?