Fixed Equipment Isolation

“PAT testing” is often used as shorthand for the in-service inspection and testing of electrical equipment. The name can be misleading, because it suggests only portable items (or appliances with a 13A plug) are included.

In practice, inspection and testing can also apply to equipment that’s connected to the fixed installation, including items wired via a fused spur. A wall-mounted heater is a common example. If it’s electrical equipment in service, it still needs to be maintained in a safe condition.

If you’re unsure what sits within scope, see: what PAT testing covers.

Why fixed equipment is often missed

Before inspection and testing can begin, the equipment must be safely isolated from the supply. With plug-in equipment this is usually as simple as unplugging it. With fixed equipment, isolation is more involved, and that’s why it’s commonly overlooked.

Safe isolation

Isolation should only be carried out by a competent person using suitable test equipment and lock-off devices. The IET Code of Practice outlines the minimum steps expected for safe isolation:

  1. Locate and positively identify the correct isolation point/device.
  2. Check the condition of the voltage indicating device.
  3. Confirm the voltage indicating device is functioning correctly.
  4. Switch off the circuit/device to be isolated.
  5. Verify that no voltage is present.
  6. Re-confirm the voltage indicating device on a known supply / proving unit.
  7. Lock off (or otherwise secure) the isolation device.
  8. Post warning notice(s).

Further information on safe isolation procedures is covered in the HSE publication HSG85.

So what are your options?

It’s common for someone to be trained and competent in routine PAT inspection and testing, but not competent to safely isolate fixed equipment. When that’s the case, you’ve got a few sensible routes.

  • Test it alongside fixed wiring inspections (EICR) where practical. Both activities require isolation, and combining them can reduce disruption.
  • Agree suitable intervals by risk assessment. Fixed equipment is often low-movement and may not need frequent testing, but you should confirm this based on use, environment and history.
  • Bring in a competent contractor if the risk assessment indicates more frequent testing is required.

The right interval depends on a risk assessment. If you want fixed equipment included during an EICR visit, you’ll usually need to request it explicitly, as it may fall outside the standard scope of the report.