Safety Tips for Working with High-Voltage Power Systems

High-voltage systems are vital to modern infrastructure, but they’re also incredibly dangerous. As a result, high-voltage workers require extensive safety training to help prepare them to recognize risks, follow proper protocols, and protect themselves and others on the job.

Below, we’ll discuss the dangers of high-voltage work, how the hazards differ from those at lower voltages, and the top safety practices that high-voltage workers must follow.

What Is High-Voltage Work?

Generally speaking, high-voltage work involves interaction with systems that carry a high enough level of voltage to inflict serious damage on the human body. While voltages as low as 50 volts can be life-threatening, high voltages present additional hazards due to the enormous energy that can be released in a fraction of a second.

The specific threshold defined as high voltage varies based on context, but for high-voltage work in the U.S., the relevant threshold is 600 volts as set by the National Electric Code (NEC), the National Fire Protection Association (NFPA) 70E standard, and various OSHA standards related to high-voltage work.

Why Safety Comes First in High-Voltage Work

OSHA considers voltages as low as 50 to be hazardous because they’re capable of causing ventricular fibrillation, respiratory arrest, or severe burns. As a result, standard 29 CFR 1910.303(g)(2)(i) requires guarding 50V+ systems against accidental contact.

However, voltages of 600 and above pose additional and severe hazards. Unprotected contact, even for short durations, can cause thermal and deep tissue injuries that often require surgery as severe as amputation.

High-voltage systems even pose serious hazards without contact. Arc flashes occur when electricity jumps across a gap in an electrical circuit, causing intense heat, severe burns, ignited clothing, and melted metal.  Arc blasts sometimes accompany arc flashes. The rapid expansion of air and vaporized metal creates a pressure wave that can create explosions, projectiles, and sound waves that may cause ruptured eardrums, concussions, and internal organ damage.

As a result, high-voltage systems require special training and additional precautions.

Top Safety Practices in High-Voltage Operations

When working with high-voltage systems, there are multiple levels of hazard mitigation required to ensure worker safety.

Know & Avoid Minimum Approach Distances

Before beginning work, everyone should be aware of the locations of all energized equipment and the applicable minimum safe distances. These distances vary based on the voltage of the equipment and whether you’re talking about approach distance or clearance distance.

Everyone must be careful to avoid entering within the minimum distances. This applies not only to individuals but to any equipment and tools.

Lockout/Tagout Procedures

In the vast majority of work scenarios, high-voltage systems must be de-energized before any work can begin.

It’s a safety process often referred to as Lockout/Tagout, or LOTO. It involves:

• Isolating All Hazardous Energy Sources. You must identify all potential energy sources and make a plan to control those sources effectively during work, disconnecting the equipment from all potential inputs. Consider all sources of electrical energy, including backup systems, batteries, and capacitors, as well as any additional sources of energy (mechanical, hydraulic, pneumatic, chemical, or thermal). Any stored energy must be released, and you should take steps to remove any source of potential or kinetic energy.
• Locking and Tagging Out. Once the system is de-energized, you need to use lockout and tagout methods to ensure that it isn’t re-energized before it’s safe. “Locks” physically prevent power from being restored or otherwise render the equipment inoperable. Tags tell anyone who comes along that they shouldn’t try to restore power. For electrical systems, locks and tags should be applied at breakers, electrical disconnects, traditional plugs, and battery backups. Various types of “locks” exist for different components, including clamp-on breaker devices and boxes to enclose an electrical plug.

Sometimes it’s necessary to perform high-voltage work on energized lines, but such “live-line” work should only be performed when it’s justified. These projects require permits and documentation that outlines the scope of the work, all hazards that may be encountered, and the mitigation measures to be used.

Wear Personal Protective Equipment (PPE)

High-voltage work should be performed with the appropriate personal protective equipment (PPE), including:

• Insulated gloves
• Safety glasses or face shields
• Flame-resistant (FR) and arc-rated (AR) clothing, also called arc flash clothing
• Dielectric (poorly conductive) footwear
• Insulated Class E hard hats

Additionally, all equipment and tools should also provide protection. All platforms, bucket trucks, or ladders should be insulated, and all tools should be rated for high-voltage applications.

Use Safety Observers

When work is being performed near live lines – whether it’s construction, tree trimming, or line maintenance – one or more safety observers should be monitoring the work at all times.

Safety observers should each be focused on overseeing the safety of a single task, so multiple tasks performed simultaneously will require multiple safety observers. Safety observers should be completely devoted to safety monitoring, not burdened with other tasks. They also need to be trained and, like a competent person, given the authority to stop or change work if necessary.

The Importance of Hands-On Learning and Refresher Training

It’s essential for high-voltage workers to have a solid foundation in understanding electrical principles, hazards, and mitigation measures, so it’s best to start with something like a power system operations course.

However, taking electrical safety courses online simply isn’t enough. Hands-on training is essential for gaining practical skills and practicing safety procedures in a controlled environment.

There are many types of hands-on training for utility workers, depending on their role. North American Electric Reliability Corporation (NERC) simulation training is a popular place to start for anyone who will be working with bulk power systems. These computer-based simulations help workers develop decision-making skills and situational awareness in complete safety. They provide an opportunity to work through emergency operations in a risk-free environment.

NERC simulation training is necessary for gaining and maintaining NERC certification. They’re available in both instructor-led courses and online interactive training.

Who Should Take High-Voltage Safety Training?

Anyone who may be exposed to high-voltage hazards in the course of their regular duties should take some degree of high-voltage safety training, regardless of whether their job title appears on a list.

That said, here are some common jobs that typically require high-voltage safety training:

• Utility workers
• Electricians (commercial or industrial)
• Electrical engineers
• Maintenance personnel
• Contractors
• HVAC installers
• Electric Vehicle (EV) technicians
• Industrial machine operators
• Electrical inspectors
• Safety managers

Get Electrical Safety Courses Online

Although there’s no substitute for hands-on training for utility workers, online courses still have a place in utility worker training.

As a NERC-recognized training provider, our courses allow you to cement your knowledge of electricity safety principles from any device with internet. You’ll be able to go at your own pace and review the material as many times as you need.

If you’re interested in pursuing high-voltage work, get started with our High Voltage and Power Systems Operations Review course by enrolling today!