Stay Safe: The Importance of High-Voltage Testing

Electricity is powerful, but only if it’s contained. When it isn’t, systems fail. People get hurt. And entire operations can go dark in seconds. You don’t want your electrical system to react to events like this. You want to prevent them from ever happening in the first place. 

That’s exactly what high-voltage testing is for.

Safety doesn’t start at the breaker. It starts, ultimately, with your cable insulation. High-voltage testing (also called dielectric testing) is a vital part of protecting your team, your cable systems, and your bottom line.

What is high-voltage testing?

High-voltage cable testing is a stress test for your cables. Technicians apply a higher voltage than what your equipment normally runs on to see if the insulation can handle the heat—literally. If it can’t, the test will find out, safely, before something else does.

This is the best way to catch hidden flaws in your insulation that would otherwise go undetected until it’s too late.

What can go wrong without it?

Even brand-new cable systems aren’t guaranteed to be perfect. Manufacturing defects, installation damage, moisture exposure or intrusion, or just years of wear and tear all compromise the quality and efficacy of your insulation. If just one section of cable fails, the result could be an outage, a fire, or a serious injury.

Some of the most common issues we find during HV testing include:

• Voids and air pockets in insulation from the manufacturing process
• Cuts or nicks from shipping or installation
• Moisture intrusion, which weakens the dielectric strength
• Thermal aging, which breaks down materials over time

These are not just technical problems; they are significant and preventable safety risks. Keep everyone safe by making sure the right testing protocols are in place. 

Proactive testing saves more than money

Yes, high-voltage (HV) testing is required for many facilities. But it’s more than a box to check off. When done regularly, it helps:

• Prevent unexpected outages
• Extend the life of your high-voltage cables and equipment
• Keep your team safer
• Reduce the risk of major losses from electrical failure

Testing at the time of installation (acceptance testing) and on a scheduled basis (maintenance testing) can catch problems early, before they turn into emergencies.

AC vs. DC testing: What’s the difference?

• AC testing simulates real-world electrical conditions and is ideal for equipment that runs on alternating current.
• DC testing is often used for simple insulation checks and requires less power.

The right method depends on the equipment, its operating voltage, and the standards you follow. Not sure which one you need? We’ll walk you through it.

Is high-voltage testing destructive?

HV testing is safe and non-destructive when done properly. HV testing is designed to stress the insulation without damaging it, unless it’s already compromised. In that case, it’s better to let it fail in a controlled test than during live operation.

Build your first line of defense with NCE

Your cable systems are the lifeblood of your facility. If the insulation fails, everything downstream suffers.

At North Central Electric, our certified technicians use state-of-the-art equipment to perform industry-leading high-voltage testing, giving you complete confidence in your system’s safety and integrity. We’ve seen firsthand how a single overlooked fault can bring an entire operation to a halt.

Contact NCE to schedule your high-voltage testing consultation and protect your system.