Arc Flash Risk & Energised Panel Assessment SWMS

An arc flash risk and energised panel assessment is the work of inspecting, testing and assessing an electrical panel that cannot be fully de-energised, to determine the incident energy and the controls needed before any energised task proceeds. It is high risk construction work under the NSW WHS Regulation 2025 because it is work on or near energised electrical installations or services (s291), so a SWMS is mandatory under s299. Energised electrical work is prohibited in every Australian jurisdiction unless de-energising is not reasonably practicable or the task meets the narrow testing and fault-finding exceptions, so the SWMS opens by testing that prohibition and documenting why energised work is justified. The defining hazard is the arc flash: an explosive release of energy that vaporises copper, produces a pressure wave and a plasma fireball reaching thousands of degrees, and that can kill or cause fatal burns without any physical contact with a live part. Alongside it sits the shock hazard from direct contact and the arc-blast pressure and shrapnel. The assessment establishes the incident energy in cal/cm², the arc flash boundary and the shock approach boundaries, the arc-rated PPE category, and the requirement for a trained safety observer, all to AS/NZS 4836. SafeWork NSW is the regulator. The output is a documented basis for safe energised work or, preferably, a justified shutdown — the SWMS makes de-energising the default and energised work the controlled exception.

Hazards identified

7 hazards covered, sorted by priority.

Control measures

Hierarchy-of-controls order: elimination → substitution → isolation → engineering → administrative → PPE.

1. 1Elimination — De-energise, isolate, lock out and prove dead so the assessment is carried out on a dead panel wherever de-energising is reasonably practicable
2. 2Substitution — Substitute remote and non-contact methods (thermography, remote racking, external metering) for hands-on energised testing wherever the data can be obtained that way
3. 3Engineering — Arc flash study to establish incident energy, the arc flash boundary and the limited-approach boundary before any energised work
4. 4Engineering — Insulated barriers, shrouding and remote operators to keep hands and tools outside the restricted approach boundary
5. 5Administrative — Energised-work justification and permit confirming de-energising is not reasonably practicable, authorised before work
6. 6Administrative — Trained safety observer stationed for the duration of all energised work, briefed on isolation and rescue
7. 7Administrative — Established arc-flash and shock boundaries with exclusion of all unqualified persons
8. 8PPE — Arc-rated clothing, hood, gloves and face shield selected to exceed the calculated incident energy (cal/cm²)
9. 9PPE — Insulated gloves tested to voltage with leather over-protectors, and insulated tools

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

At 5:30 am, before the building load picks up, an authorised electrician from Vantage Electrical is tasked to assess a main switchboard a tenant says cannot be shut down. The supervisor first challenges that: a load study shows the board can in fact be de-energised over a 90-minute window at change of shift, so the assessment is rescheduled to be done dead, proved with a tester verified before and after. Where a small section genuinely cannot be isolated, the arc-flash study puts the incident energy at 9 cal/cm² at working distance; the electrician dons a rated 25 cal/cm² kit, sets the arc-flash boundary with barriers, and a trained safety observer takes position with the isolation point briefed. Non-contact thermography captures most of the data without opening a live cubicle. When a single live measurement is unavoidable, it is taken with an insulated probe from outside the restricted boundary, observer watching, and the cubicle is closed immediately after. The assessment report recommends a permanent shutdown procedure so future work on the board is done dead.

Related legislation

• WHS Act 2011 (model)
• WHS Regulation 2025
• Managing Electrical Risks in the Workplace Code of Practice
• AS/NZS 4836:2023

Frequently asked questions