Industrial equipment testing for motors, welders, compressors, and heavy machinery.
Three Phase Testing
Overview
Industrial Equipment Testing & Compliance
Three-phase testing covers the inspection and electrical safety testing of industrial equipment that operates on three-phase power — including motors, welders, compressors, conveyor systems, pumps, an...
- Three-phase equipment operates at higher voltages and currents than standard appliances, making electrical faults significantly more dangerous — arc flash, electrocution, and fire risks are all elevated.
- Industrial equipment is subject to extreme operating conditions — vibration, heat, dust, moisture, and chemical exposure — that accelerate wear on cables, connectors, and insulation.
- Phase imbalances can cause motor overheating, premature bearing failure, reduced efficiency, and in severe cases, winding burnout and fire.
- Regular testing identifies developing faults before they cause unplanned equipment failure, costly production downtime, or workplace injuries.
Insulation
PASSPhase Balance
PASSRunning Current
PASSWhy It Matters
Why Three Phase Testing matters
Three-phase equipment operates at higher voltages and currents than standard appliances, making electrical faults significantly more dangerous — arc flash, electrocution, and fire risks are all elevated.
Industrial equipment is subject to extreme operating conditions — vibration, heat, dust, moisture, and chemical exposure — that accelerate wear on cables, connectors, and insulation.
Phase imbalances can cause motor overheating, premature bearing failure, reduced efficiency, and in severe cases, winding burnout and fire.
Regular testing identifies developing faults before they cause unplanned equipment failure, costly production downtime, or workplace injuries.
WorkSafe NZ expects documented evidence that industrial electrical equipment is maintained in a safe condition.
Common Issues
Common Three Phase Testing faults
Failed insulation resistance
Current leaking between conductors or to earth through degraded insulation — a serious fire and shock hazard in industrial environments.
Equipment removed from service immediately for professional repair or replacement.
Phase imbalance
Uneven current draw across phases causes motor overheating, premature bearing failure, reduced efficiency, and potential winding damage.
Investigated to determine cause — may indicate supply issues, winding faults, or uneven mechanical loading. Motor may need replacement.
High running current
Equipment drawing more than its rated current indicates overloading, mechanical binding, or electrical faults — all leading to overheating and premature failure.
Equipment inspected for mechanical issues, overloading, or electrical faults. Load assessment recommended.
Damaged connectors or cable glands
Exposed conductors at high voltage create an immediate risk of arc flash, electrocution, and fire.
Connector or cable gland replaced with correctly rated industrial-grade component and equipment retested.
Testing Frequency
How often should you test?
Inspection & Testing Intervals
Recommended inspection and testing frequencies based on AS/NZS 3760 for different workplace environments and equipment types.
Caution
This information should be read together with the AS/NZS 3760 standard as a whole, particularly Clause 2.1. Inspection intervals vary depending on equipment type and operating environment.
| Type of environment and/or equipment (a) | Equipment including Class I equipment, Class II equipment, cord sets, cord extension sets and EPOD’s (b) | Interval between inspection and tests | |||
|---|---|---|---|---|---|
| Residual Current Devices (RCD’s) | |||||
| Push Button test by user | Operating time and push-button test | ||||
| Portable (c) | Fixed (d) | Portable (e) | Fixed (f) | ||
1. Factories, workshops, places of work or repair manufacturing, assembly, maintenance or fabrication | 6 months | Daily, or before every use, whichever is the longer | 6 months | 12 months | 12 months |
2. Environment where the equipment or supply flexible cord is subject to flexing in normal use OR is open to abuse OR is in a hostile environment | 12 months | 3 months | 6 months | 12 months | 12 months |
3. Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment | 5 years | 3 months | 6 months | 2 years | 2 years |
4. Residential type areas of hotels, residential institutions, motels, boarding houses, halls, hostels, accommodation houses, and the like | 2 years | 6 months | 6 months | 2 years | 2 years |
5. Equipment used for commercial cleaning | 6 months | Daily, or before every use, whichever is the longer | NA | 6 months | NA |
6. Hire Equipment Inspection | Prior to hire | Including push-button test by hirer prior to hire | NA | NA | NA |
Test and Tag | 3 months | NA | NA | 3 months | 12 months |
7. Repaired, serviced and second-hand equipment | After repair or service which could affect electrical safety, or on reintroduction to service, refer to AS/NZS 5762 | ||||
1Factories, workshops, places of work or repair manufacturing, assembly, maintenance or fabrication
2Environment where the equipment or supply flexible cord is subject to flexing in normal use OR is open to abuse OR is in a hostile environment
3Environment where the equipment or supply cord is NOT subject to flexing in normal use and is NOT open to abuse and is NOT in a hostile environment
4Residential type areas of hotels, residential institutions, motels, boarding houses, halls, hostels, accommodation houses, and the like
5Equipment used for commercial cleaning
6Hire Equipment
Inspection
Test and Tag
7Repaired, serviced and second-hand equipment
After repair or service which could affect electrical safety, or on reintroduction to service, refer to AS/NZS 5762
Important Note
Inspection frequencies depend on equipment type, condition, and working environment. Hostile environments require more frequent inspection and testing. Always refer to AS/NZS 3760 or contact our team if you are unsure which interval applies to your workplace.
Our Process
How Three Phase Testing works
Our streamlined process ensures every three phase testing engagement is efficient, thorough, and fully documented.
Equipment Identification
Our technician identifies all three-phase equipment on site and records make, model, serial number, location, and power supply details for each item.
Visual Inspection
Each item is inspected for damage to plugs, connectors, cable glands, cables, and equipment housings. Environmental factors such as dust, moisture, and chemical exposure are assessed.
Electrical Testing
Calibrated industrial test equipment runs insulation resistance, earth continuity, phase balance, and running current tests. De-energised tests are performed first, followed by energised measurements where safe to do so.
Result & Tagging
Pass or fail result recorded for each item. Durable QR-coded compliance tag applied. Failed items are tagged, documented, and reported immediately.
Digital Reporting
Full compliance report with test results, phase balance data, running current measurements, and recommendations delivered to your online portal within 24 hours.
What's Tested
Three Phase Testing checklist
Insulation Resistance
500V/1000V DC testing between all phase conductors and earth to verify insulation integrity and identify degradation before breakdown occurs.
Earth Continuity
Verification of protective earth continuity across all three phases and equipment chassis, ensuring fault current can safely trip circuit protection.
Phase Balance
Measurement of current draw across all three phases during operation to identify uneven loading that causes motor overheating and premature failure.
Running Current
Measurement of actual operating current against the equipment's rated capacity to identify overloading, mechanical issues, or electrical faults.
Visual Inspection
Thorough examination of plugs, connectors, cables, cable glands, enclosures, and equipment housings for damage, wear, or environmental degradation.
Tag Application
Durable test tags with QR codes applied to each tested item showing test date, result, and next due date.
What You Receive
What you receive
Three-Phase Test Report
Detailed report with insulation resistance values, earth continuity readings, phase balance measurements, running current data, and pass/fail status for every item tested.
QR Asset Labels
Each tested item receives a QR code linking to its complete test history, compliance status, and next test due date.
Compliance Certificate
Formal certificate confirming all three-phase equipment has been tested and meets safety requirements, suitable for regulatory and insurance purposes.
Online Portal Access
24/7 access to test results, compliance status, and historical data for all three-phase equipment through your secure online portal.
Automated Reminders
Email alerts when equipment is approaching its next test due date, helping you maintain continuous compliance.
Benefits
Why choose our three phase testing service
Industrial Expertise
Technicians trained specifically in high-voltage industrial equipment testing and fault diagnosis.
Complete Testing
Insulation resistance, earth continuity, phase balance, and running current tests on every item.
Minimise Downtime
Efficient testing scheduled around production timelines to minimise operational disruption.
AS/NZS 3760 Compliant
Full compliance with the New Zealand standard for industrial three-phase equipment.
Industries We Serve
Trusted across New Zealand's key industries
FAQ
Three Phase Testing FAQ
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