IT PAT Testing Guide: Safe Electrical Testing for Networking Gear

Q: Can standard PAT testing damage networking equipment?

Yes. Standard high-current electrical tests can damage delicate circuit boards. To protect networking hardware, technicians should use a low-current continuity test (100mA-200mA) and a reduced insulation voltage of 250V DC.

Q: How often should server room equipment be PAT tested?

Under IET 5th Edition guidelines, frequency is determined by risk assessment. Static equipment in server rooms can often go up to 5 years between tests, while mobile assets like laptops should be inspected every 12 months.

Q: Do I need to shut down my network for electrical testing?

For managed switches and servers, a controlled shutdown is recommended to avoid disk errors. In redundant setups, you can test individual power supplies one at a time to maintain system uptime.

Q: How do I test laptop chargers and power leads safely?

Laptops are classified as Class II, but their detachable power cables should be tested separately as Class I. This ensures the cable is safe without exposing the low-voltage device to unnecessary test currents.

Ensuring the safety of IT infrastructure requires a specialised approach to PAT testing (now formally known as EET or Electrical Equipment Testing). Standard testing procedures designed for heavy machinery or kitchen appliances can be catastrophic for sensitive networking hardware.

This guide outlines the critical protocols for maintaining compliance without risking hardware failure or data loss.

1. Critical Safety Protocols for IT Infrastructure

Modern electronics utilise delicate circuit boards that cannot withstand standard “hard” electrical tests. To protect your hardware, follow these mandatory adjustments:

Low Current Continuity: Standard 10A or 25A bond tests can vaporise internal PCB tracks. Use a soft test current of 100mA to 200mA.
Reduced Insulation Voltage: Traditional 500V DC tests can destroy surge suppression components. Perform insulation resistance tests at 250V DC to ensure component integrity.
Avoid Forced Load/Leakage Tests: Power cycling servers or devices with hard drives mid-test can cause disk read/write errors. Only perform “run” tests if strictly necessary and after a controlled shutdown.

2. Networking and Server Room Requirements

Testing in a data center or server room environment requires more coordination than a standard office walkthrough.

Managed Shutdowns & Redundancy

Unlike a simple appliance, network switches and servers require a planned outage. For high-availability environments:

Dual Power Sources: For servers with redundant PSUs, test one power supply while the other maintains system uptime.
UPS Systems: Uninterruptible Power Supplies are Class 1 items. They require specialised care to ensure battery backups do not interfere with resistance readings.

Static vs. Portable Assets

While server racks and switches are often “fixed,” their detachable power leads remain a primary point of failure and must be inspected and tested regularly.

3. IT Asset Classification & Test Requirements

Item Type	Electrical Class	Key Test Requirement
PC Towers & Servers	Class I (Earthed)	Earth continuity, 250V insulation.
Laptops	Class II	Test the detachable mains lead separately as Class I.
Monitors (TFT/LED)	Class I or II	Check manufacturer labels; do not probe vents.
Routers & Hubs	Class II / SELV	Test the external PSU rather than the low-voltage device.
Extension Leads	Class I	Mandatory polarity check to ensure no crossed wires.

4. Recommended Testing Intervals (IET 5th Edition)

Under the Electricity at Work Regulations 1989, frequency is determined by risk assessment. Based on the IET 5th Edition Code of Practice, typical intervals include:

Laptops & Mobile Gear: Every 12 months (high risk due to frequent movement/cable strain).
Desktop PCs & Monitors: Every 2–4 years in low-risk office settings.
Server Room Equipment: Up to 5 years, as these are static and low-risk once commissioned.

5. Compliance & Documentation

Post-testing documentation is essential for insurance and health and safety audits. A compliant EET service must provide:

1. Asset Register: A comprehensive inventory of all IT hardware.
2. Detailed Test Results: Quantifiable readings for earth bond and insulation resistance.
3. Pass/Fail Labelling: Distinct stickers on both the appliance and the specific power lead.

Expert Tip: Before any testing begins, ensure the technician is using a dedicated IT-safe PAT tester. Cheap, generic testers often lack the 250V setting, leading to “phantom fails” or, worse, fried motherboard components.

Q: Can standard PAT testing damage networking equipment? A: Yes. High-current “hard” bond tests (10A or 25A) can vaporise internal PCB tracks. To protect sensitive IT hardware, always use a “soft” test current of 100mA to 200mA and reduce insulation voltage to 250V DC.

Q: How often should server room equipment be PAT tested? A: According to IET 5th Edition guidelines, static server room equipment is typically considered low-risk and may only require testing every 5 years once commissioned. High-use mobile gear like laptops should be tested every 12 months.

Q: Do I need to shut down my network for electrical testing? A: Managed switches and servers require a planned outage for safe testing. In high-availability environments, you can maintain uptime by testing one PSU at a time for devices with redundant power supplies.

Q: How do I test laptop chargers and power leads safely? A: Laptops are Class II devices, but their detachable mains leads should be tested separately as Class I items. This ensures the primary point of failure – the cable – is fully verified without risking the laptop itself.

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