December 2024-January 2025 Q&A
Q: Here in Australia, we recently read Jim Vaughn’s “Trainer the Trainer 101: Substation Entry Policies” (https://incident-prevention.com/blog/train-the-trainer-101-substation-entry-policies/). We have a 415-volt substation on-site; its doors and cabinets are locked. However, we are not comfortable allowing entry to the substation without some control over who is able to enter and the qualifications they must have. Do you know of any reference materials pertaining to entry requirements for non-qualified electricians, or is allowing them entry simply a no-no? We appreciate any help you can provide.
A: We are glad to hear from Australia and gratified to know that Incident Prevention magazine’s reach is becoming more international. Because we are based in the U.S., we are not experts on Australian labor law, but we do have colleagues who are members of the International Electrotechnical Commission (IEC). We’ve had some discussions over the years with Australian IEC members made possible by those colleagues. As it turns out, because today’s ability to exchange information in real time has made our work environments more uniform, Australia has work practices that have become somewhat universal.
We know that Safe Work Australia (www.safeworkaustralia.gov.au) has rules for employers and safety directors that mirror international standards. The only issue is whether your local enforcement jurisdiction has adopted the principles found in Safe Work Australia’s Model Codes of Practice.
Those codes require the employer – often referred to in Australia as a “person conducting a business or undertaking” or “PCBU” – to assess the workplace and ensure workers are not exposed to hazards. We think the most important practice is ensuring the competency of workers who could be exposed to energized electrical equipment. The definition varies slightly from source to source, but “competent” typically refers to a person trained, tested and qualified by the employer to understand and avoid the risks associated with their job tasks.
We don’t think your company’s integrated alliance is classified as an electric utility. That means your workers would fall under the code of practice intended to prevent their exposure to energized work unless there were no reasonable alternative; this would prohibit substation entry by individuals who are not specifically qualified to identify and control their exposure hazards.
As with most international standards, Safe Work Australia requires the employer/PCBU – even where no rule exists that defines safe work practices for substation entry – to consider all risks associated with the work, not just those covered by regulations and codes of practice.
The bottom line is that you have a responsibility to assess the workplace and establish safety and health standards that ensure your employees are not unnecessarily exposed to uncontrolled hazards.
Good luck, keep in touch, and let us know how things go.
Q: Our company has a rule that requires use of a portable equipotential mat when switching, but a question came up: How good is this type of mat – or any mat – if it is underwater due to heavy rain?
A: Thanks for sending us this question. We’re going to provide a very detailed answer because although the answer is as simple as yes, use of a portable equipotential mat does make a difference even in water, it’s important that readers understand why that’s the case.
The answer depends on the resistance of the path between the structure and the worker’s feet (touch potential) or the resistance between the worker’s feet (step potential). Whether ground is dry, damp or soaked makes a big difference in voltage (potential) and the level of the hazard to the worker.
Keep this in mind as we dig through the weeds here to understand the risk. Touch potential creates a parallel path with the structure, which will very likely include a division of total fault current between the path through the structure and the path through the worker touching the structure. That is not the case with step potential. Electrical current cannot flow across the earth’s surface without a complete electrical path to ground, and there is no complete horizontal path as opposed to down into the earth along the path of the structure, which is the earthing electrode. Voltage can flow horizontally, but that’s only because a conductive element in earth gains a charge from the conductive element next to it and passes it on to the next conductive element simply by transfer of electrical charge. Electrical current cannot do that. Voltage without a current component is rarely deadly. Although fatal step-potential injuries occasionally occur in non-power-line exposures, they are very rare in power-line exposures.
Regarding touch potential, the goal of the equipotential mat is to electrically bond the structure and the worker touching the structure to prevent a potential difference between the two. In the case of structure-mounted switch operator handles, this is the lesser of the issues. Even if a portable mat were underwater, we suggest that protection would not be degraded for a worker standing on that mat, which is electrically bonded to the structure. We also know that wet ground is highly conductive, so it is very likely that if a worker is within reach of the structure, the distance between the worker’s feet and the structure is very short. Since the resistance is very low across the wet soil and the distance is very short, the potential difference across that distance is likely to be negligible. However, it’s not guaranteed to be completely without risk, so the equipotential mat is appropriate. Now, the earth-potential argument is based on principle and theory, lacking the assurance of a physical bond across the gap provided by the portable mat. The point here is that there is low risk to the worker with their hands on the switch operator handle in water, but those conditions cannot be assured – whereas using the portable mat ensures protection of the worker even in water.
The step-potential hazard in the gap between a worker’s feet is similar when assessed based on principle and theory. First, we must understand the IEEE definition of step potential as related to the voltage developed across the resistance of the earth 3 feet apart. That might be a good working definition, but on the ground, the distance does not matter. Voltage flowing across a resistance creates a potential across that resistance proportional to the voltage available and the resistance between the two points, distance notwithstanding. Like the issue of touch potential, the relative risk is the resistance in the gap, not the voltage crossing the ground. A worker standing with their feet together in highly conductive, wet, low-resistance earth is not likely to be exposed to a high-potential voltage. But as with the touch-potential principle, the resistance and voltage conditions at the time cannot be known; thus, we cannot assume the level of risk without commonly bonding that space between the worker’s feet through use of a portable mat or by insulating the worker’s feet.
Trying to manage the use of a portable vinyl mat in water must be difficult and might create a tripping hazard. Perhaps a vendor will invent a portable EPZ mat constructed with some form of non-floating material or a lightweight, rigid, conductive screen. We hope this detailed answer to your question helps you and other readers better understand both the risk and remedy. Keep in touch and let us know how the discussion goes.
Q: We spoke about underground distribution transformers last year during an iPi Monthly Forum (https://ip-institute.com/ipi-forum/), and I was wondering if you could provide some insight on overhead this time. We have a process called “half-tapping” or “back-tapping” of a pole-top transformer. Here is the wording: “Method for ‘piecing out’ (transferring) existing energized taps to a newly installed live conductor: This method is commonly practiced in the field, and it is known as ‘half-tapping’ or ‘back-tapping.’ This method allows an energized piece of equipment (e.g., a pole-top transformer) to remain energized while transferring load from existing primary conductors to newly installed primary conductors.”
This has been done in the past but hasn’t been taught in school; it is considered something to be learned during on-the-job training. It also hasn’t been taught in the field in quite some time. The process does mention proper isolation using rubber goods as well as proper PPE for live work. Are you aware of this process? Do you have any information that could help us better understand it?
A: What you’re referring to is a practice often used to keep a transformer in service while transferring load to a new three-phase system. It’s pretty much an old-school practice as the rule back then was no outages, especially if the transfer affected several transformers in a line section. Today, following the hierarchy of controls, many utilities take an outage as the preferred alternative to an energized transfer.
With planning, experience and proper cover-up, this practice is legal and can be done safely. The process is to spread the old phases; pull in and energize the new phases; and parallel tap all the transformers to both the old system and the new system. From there, crews go back to each bank or transformer and untap the old feed, leaving the transformers on the new feed. The parallel phase taps were always Kearney-squeezed on above the transformer fuse.
This is not a task for new or apprentice lineworkers, especially on two- or three-pot banks. Single pots are easy to half-tap, but utilities most often take outages on three-pot banks.
Without close supervision of workers and a true commitment to safety, cover-up as a policy can be a real problem; that’s because crews moving from pole to pole to half-tap a single transformer don’t want to slow down to cover up. That’s no excuse at all. It is possible to glove on the new tap and stay below the feeder, but crews should always blanket the dropout switch while they bug-on the tap.
Q: We are a small distribution contractor with eight trucks. Recently, while returning from storm restoration work in North Carolina, we were stopped by state troopers in two different states. In one state, the troopers had all our drivers get out and talk to them while they assessed the drivers for alertness, or that’s what we assume. They let the crew continue driving. In the second state, the troopers cited all of our drivers for record-of-duty-status (RODS) violations. We thought we had an emergency exemption. The troopers said the ride home is not considered an emergency under Federal Motor Carrier Safety Regulations (FMCSR) and that RODS applies. What are your thoughts?
A: It is a distinct possibility that some readers who respond to storms are not necessarily going to agree with our answer, but please don’t ignore this advice. During every storm response event, our industry sees crashes on the way home that often include serious injuries and fatalities. The Federal Motor Carrier Safety Administration (FMCSA) has exemptions for some of its regulations – such as hours of service and RODS – but there are limits. Specifically, 390.23(b) states the following: “Except as provided in paragraph (b)(1) of this section, §§ 395.3 and 395.5 of this chapter shall not apply to a motor carrier or driver operating a commercial motor vehicle so long as the motor carrier or driver is providing direct assistance during an emergency declared by the Governor of a State, their authorized representative, or FMCSA during the emergency period or 14 days from the date of the initial declaration of emergency, whichever is less.”
The FMCSA further states in 390.23(e)(3) that when “the driver has been relieved of all duty and responsibilities upon termination of direct assistance to an emergency relief effort, no motor carrier shall permit or require any driver used by it to drive, nor shall any such driver drive in commerce, until the driver has met the requirements of §§ 395.3(a) and (c) and 395.5(a) of this chapter.”
We’ve seen internet commentary from lineworkers who were stopped after recent storm restoration efforts. Some comments included hasty criticism of law enforcement, but that criticism is out of place. The practical defense of highway rules enforcement is right in our own metaphorical backyard. Lineworkers demand that our brothers and sisters work safely, that our employers provide the tools and support to keep us safe, and that each of us follows the rules to make it safe to work even in the harshest of conditions. None of that is any different than the FMCSA rules that are designed to keep drivers and the public safe. When you leave the bucket for the cab, you become a commercial motor vehicle (CMV) driver maneuvering a multi-ton vehicle at interstate speeds – and there are rules. The rules are based on practical experience. And just as in line work, the rules are to be followed to prevent accidents.
There are a few voices in our industry asking storm restoration managers to recognize that exhausted lineworkers are a hazard to themselves and the public. Planners should recognize that the FMCSA explicitly requires CMV drivers to follow the RODS and hours-of-service rules once they’re relieved from emergency restoration duties. Driving home is not part of the emergency, so driver logs apply, meaning that in compliance with federal rules, a driver leaving North Carolina must have a log entry showing 34 off-duty hours before they begin the trek home.
By the way, the FMCSA is very clear that “on-duty not driving” is any work for the employer that does not include driving duties. Yes, that seems impractical, but a very easy solution is to ferry return drivers to the storm location to begin those drives home.
The FMCSR exception has been around for a long time and many states give some leeway on enforcement. Interstate communications among highway law enforcement officers have put a spotlight on the number of line-truck crashes that occur, and the trends have been noted. Some of us have already heard that more states may be tightening up on enforcement of the return-home “end of exception.” So, as planners, we should be finding solutions to follow the law. There really is no excuse for lineworkers putting in 16-hour days for three to four weeks without incident during a storm restoration effort – only to fall asleep and crash on the drive home. We think sending fresh workers to drive trucks home at the end of deployment is one good solution.
Do you have a question regarding best practices, work procedures or other utility safety-related topics? If so, please send your inquiries directly to kwade@utilitybusinessmedia.com. Questions submitted are reviewed and answered by the iP editorial advisory board and other subject matter experts.
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