Define the access event
Be clear about who opens the guard, why, how often and what hazardous functions are present at that point.
GUARD INTERLOCKING
AS/NZS 4024.1602 machine guard interlocking devices
A focused guide to the interlock decision: how a movable guard and the machine control system work together when access is required.
FROM STANDARD TO SCOPE
Four conversations to have before the layout is locked
Use AS/NZS 4024.1602 to turn access requirements into a credible interlocking concept. The exact decisions still depend on the machine, tasks, risk assessment and current authorised standard.
Understand stopping behaviour
The machine response, stopping time and residual hazards influence whether simple interlocking or guard locking may be required.
Reduce defeat incentives
Position and select devices with foreseeable manipulation in mind, while keeping legitimate access workable.
Validate the complete function
The device, actuator, wiring, logic, guard and machine response need to operate as one safeguarding function.
WHY IT MATTERS
An interlock is a system decision—not a switch on a door
A credible solution starts with the access task and machine behaviour, then brings the physical guard, device selection and safety-related control function together.
THE COMPLETE DESIGN PICTURE
One standard rarely works alone
Risk assessment, physical guards, safety distances, interlocking, unexpected start-up and emergency-stop functions are connected. Follow the regional hub to move between the relevant guides without losing the project context.
Edition and jurisdiction note
AS/NZS 4024.1602:2025 is publicly identified as the current joint adoption of ISO 14119:2024. Confirm current status before specifying. Standards and guidance support—not replace—a project-specific risk assessment, applicable WHS/HSWA duties, regulator guidance and competent professional advice.
COMMON QUESTIONS
AS/NZS 4024.1602 FAQs
Does every access door need guard locking?
No. The need depends on risk, stopping behaviour and whether a person could reach the hazard before the danger has passed.
Is a safety switch enough by itself?
No single component establishes the safety function. The guard, device, installation, control system and machine response must be considered together.
Can the interlock restart the machine when the door closes?
Closing a guard should not be assumed to make automatic restart acceptable. Restart behaviour requires specific assessment and design under the applicable standards.
Turn the standard conversation into a buildable guard layout.
Send the machine layout, photos and access requirements. We’ll help shape a practical modular guarding concept for your project team to assess.
Start the guarding conversationCommercial information only. This page is not legal, engineering or certification advice and does not reproduce the controlled requirements of the standard.
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