Medium and High Voltage Training: For Qualified AND Exposed Workers
With medium and high voltage, you don’t have to touch anything to get hurt. You just have to get too close. And the person who gets too close usually isn’t the electrician.
When most companies think about medium and high-voltage training, they picture the crew that switches, grounds, and maintains equipment over 1,000 volts. That crew needs it, no question. But they aren’t the only people on site who can be hurt by that equipment.
Herzig Engineering’s High-Voltage Qualified Electrical Worker Training isn’t just for your qualified electricians. It’s for any worker who could be exposed to medium or high voltage: anyone who works in proximity to energized MV/HV equipment, even if they never switch or operate it.
A quick note on terms: in the field, “medium voltage” and “high voltage” get used side by side. Equipment like 4160V generators and switchgear is usually called medium voltage, while the National Electrical Code groups everything over 1,000 volts under its high-voltage rules. The hazards, and this training, apply to both.
Qualified vs. Exposed: Same Equipment, Same Hazard
Operating the system and being exposed to it are two different things. The hazard doesn’t care which one you’re doing.
Think beyond the electrical crew. A generator mechanic working on a 4160V unit, a scaffolder building a platform in a substation, a millwright or contractor working near live gear: none of them are “operating” the system, but all of them are exposed to it. If they don’t understand the hazard, they’re at risk.
That isn’t a small group. Between 2011 and 2021, 69% of U.S. electrical fatalities were workers in non-electrical occupations, a pattern we covered in Electrical Safety Training for Non-Electrical Workers. Medium and high voltage make that gap more dangerous, not less.
Proximity Is the Hazard
At low voltage, you generally have to make contact to get hurt. Medium and high voltage change the rules. Above 1,000 volts, electricity can arc through the air to a person, or to an object they’re holding, that gets too close. No touch required.
That’s why the rules are written in distances. OSHA requires that an unqualified person working near overhead lines, together with the longest conductive object they may contact, stay at least 10 feet from unguarded energized lines of 50 kV or less, and farther at higher voltages. NFPA 70E sets approach boundaries around exposed energized parts, and unqualified workers may not cross the limited approach boundary unless a qualified person advises them of the hazards and escorts them.
Notice the phrase “the longest conductive object.” A ladder, a pole, a length of pipe, a tape measure: whatever is in a worker’s hand extends their reach. This training teaches workers to recognize approach boundaries and the hazards of proximity before they put themselves in harm’s way.
A Real Example: The Tape Measure
Distances on paper can feel abstract. One story makes them real.
A couple of years ago at a SaskPower site, a scaffolder was brought into a substation and told to measure up for a platform. He raised a metal tape measure over his head, and once it got within 10 to 15 feet of the high-voltage lines, it flashed over and gave him severe burns.
Nothing about his assignment was electrical. He was asked to take a measurement, and he did what anyone would do to measure for a platform: he raised the tape. No one had explained that the tape was now part of his reach, or how close was too close. He wasn’t an electrician. But if he’d had high-voltage awareness training, he’d have understood the danger before he ever raised that tape. That’s who this course protects.
The trap: The hazard never showed up on his work order. “Measure for a platform” doesn’t sound like electrical work, which is exactly why nobody thought he needed electrical training.
Who on Your Site is Exposed?
Do you have workers who aren’t electricians but still end up in close proximity to medium or high-voltage equipment while it’s energized? Those are exactly the people this course is built to protect. Start with the roles that show up in substations, switchgear rooms, and generator yards:
• Generator Mechanics & Technicians. Servicing engines, controls, and enclosures on 4160V and other medium-voltage units while nearby gear stays energized.
• Scaffolders & Riggers. Building platforms and lifting loads inside substations and around overhead lines.
• Millwrights & Mechanical Contractors. Working on motors, drives, and conveyors fed by medium-voltage switchgear.
• Crane, Boom & Aerial Lift Operators. Moving equipment whose reach can close the gap to an overhead line in seconds.
• Painters, Insulators & Cleaning Crews. Coating, cleaning, or maintaining structures inside energized yards and electrical rooms.
• Supervisors & Safety Staff. The people who plan the work, write the permits, and walk contractors onto site.
What the Training Covers
Herzig’s two-day, 16-hour course is led by experienced electrical safety professionals and built to NFPA 70E. It pairs arc flash and shock fundamentals with the hands-on switching and grounding practices medium- and high-voltage work demands, and qualified electrical worker certification is included.
• The three electrical hazards: electrocution, arc flash, and arc blast
• Approach boundaries, incident energy, and correct PPE selection
• Available fault current and its impact on hazard level
• System grounding: step, touch, and transferred potentials, and applying temporary grounds
• Medium- and high-voltage switching: single-line diagrams, switching sequences, and safe isolation and lockout
• Safe work practices, procedures, permits, and job/hazard planning
Delivered your way: in person at your facility on your own equipment, through live, instructor-led Virtual Interactive Training, or through Open Registration when you only need to send one worker or a few.
Compliance and Duty of Care
NFPA 70E and OSHA expect employers to train workers who are exposed to electrical hazards, not just the ones performing electrical work. OSHA’s electrical training requirements (29 CFR 1910.332) apply to employees who face a risk of electric shock, and they specifically call for unqualified workers to be trained in the safety-related work practices that protect them. NFPA 70E likewise requires unqualified persons to be trained in, and familiar with, the electrical safety practices necessary for their safety.
Extending this training to your exposed workforce is both a safety win and a documented due-diligence step. When a mechanic or contractor is hurt near energized gear, one of the first questions asked is what they were trained to recognize.
Train Everyone Who's Exposed, Not Just Everyone Who's Qualified
Your qualified crew already knows the hazard. The mechanic, the scaffolder, and the contractor walking past energized gear may not. Herzig Engineering will help you identify who on your site is exposed and build a medium- and high-voltage training plan that covers both groups, so everyone goes home safely.
Learn more at herzigengineering.com/services/safety-training or click the “Get HV Training” button below to connect with one of our electrical safety training experts.
816.734.8300 · Hello@HerzigEngineering.com
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