In industrial electrical engineering, protecting people matters more than keeping machines running.

Standard circuit breakers are designed to protect cables, not people. But in factories and commercial facilities, a sudden return of power can be deadly—especially if machines restart unexpectedly while someone is inspecting or repairing them.

To prevent this, professionals install an Undervoltage Release (UVR). This smart device turns a regular breaker into a fail-safe disconnector, cutting off power anytime voltage is lost. It ensures machines stay off until a manual reset is performed—just as Australian safety laws require.

Fail-Safe by Design

Unlike a shunt trip that requires power to disconnect, a UVR does the opposite.

It keeps the breaker closed only while power is flowing. The second voltage drops—even slightly—the device trips the breaker using spring-loaded force. If a wire comes loose or the site loses power, the UVR disconnects the machine instantly.

To restore power, a technician must manually reset the breaker—keeping things safe and deliberate.

Complies with AS 4024 Machinery Safety

Australian Standard AS 4024 says that industrial machines must not restart automatically after a blackout if it could be dangerous.

A UVR makes compliance easy. It ensures machines like table saws, presses, and conveyors don’t restart on their own. The operator must always reset the switch before the system reboots.

This is especially useful in small to mid-size machines that don’t use PLCs (Programmable Logic Controllers).

Protects Motors During Brownouts

Besides safety, undervoltage releases protect your gear.

During a voltage dip, electric motors pull more current to keep running. That overheats the windings fast—and can cause serious damage.

A thermal overload relay takes time to react. But a UVR trips instantly, shutting down power before the damage occurs. It’s cheap insurance for extending motor lifespan.

Seamless Fit with Schnap Electric Products

Schnap undervoltage releases are precision-engineered to clip directly onto their MCBs and MCCBs. No hacks. No mismatches. No compromise on safety.

They're available in:

• 240V AC – for mains-level monitoring
• 24V DC – for low-voltage control circuits

Always match the voltage correctly. The wrong unit can burn out or fail to trip when needed.

Emergency Stop Circuit Wiring

UVRs are ideal for wiring Emergency Stop (E-Stop) buttons.

These buttons connect in series with the UVR coil. If anyone presses an E-Stop or a cable gets cut, the circuit opens. The UVR trips the breaker, and the machine shuts down.

This design is self-monitoring. Even if the wiring fails, it fails in a way that kills power—making it far safer than shunt trips.

Only Use Verified Products

Cheap, unbranded UVRs may:

• Fail to trip in an emergency
• Cause nuisance tripping due to weak coil design
• Jam inside incompatible breakers

That’s why pros source from a reputable electrical wholesaler like SCHNAP Electric Products. Every UVR is matched to a certified breaker. The mechanical pins align perfectly. The products come with datasheets, RCM compliance, and real-world reliability.

Don’t mix brands. It’s not compliant and could void your switchboard certification.

Conclusion

An undervoltage release isn't just an accessory—it's a life-saver and a machine saver.

It makes sure that when the power fails, everything stays safely off.

By choosing quality gear like Schnap Electric Products, wiring it right, and following AS 4024, Australian installers can protect both people and property with confidence.