High Voltage Switching & Access SWMS

High voltage switching operations cover the authorised energising, de-energising, isolating, and earthing of HV apparatus by a designated switching operator. The work includes the issuance and cancellation of access permits and sanction-for-test certificates, the operation of HV switchgear (oil, vacuum, SF6, and air-insulated), and the establishment of safe working zones for downstream electrical work. Switching is High-Risk Construction Work under WHS Regulation s. 291 because the operator is in physical proximity to energised HV apparatus throughout the operation, and any error — incorrect circuit identification, premature permit cancellation, missed earth — propagates immediately to downstream workers under the permit. The applicable practice framework is AS 2067 (Substations and high voltage installations exceeding 1 kV a.c.) supplemented by the network operator's switching procedure manual; ENA NENS 04 (the industry National Electricity Network Safety Code) is widely adopted as the operational baseline for distribution-network switching but is industry guidance rather than a binding standard. State Electrical Safety Acts impose additional licensing and authorisation conditions on switching operators, with material differences between jurisdictions — NSW requires explicit authorisation under the Electrical Safety Office framework, VIC under Energy Safe Victoria, QLD under the Electrical Safety Office. This SWMS template covers the planning, execution, and documentation of HV switching operations.

Hazards identified

9 hazards covered, sorted by priority.

Control measures

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

1. 1Authorised switching operator only — the operator must hold current network operator authorisation for the switching class and the specific substation or network section. Authorisations are not transferable between networks.
2. 2Switching schedule prepared in advance and independently verified by a second authorised person. The schedule lists the switching steps, the safety zone established, and the permit holders to whom access will be granted.
3. 3Pre-switching brief covering the schedule, the equipment to be operated, the access permits to be issued, the personnel involved, and the rollback procedure if the switching cannot complete safely.
4. 4Switching-by-instruction prohibited — the operator executes only the written schedule, not verbal direction. Verbal instructions during execution must be confirmed back and re-issued in writing.
5. 5Test-before-touch using a calibrated HV voltage detector before any earth is applied or any access permit is issued. The detector must be proven on a known live source immediately before and after the test.
6. 6Earthing applied at all reasonably accessible points within the worked section before the access permit is issued. Earths are inspected visually as part of permit issuance.
7. 7Access permit issued by the switching operator and acknowledged in writing by the permit holder before any worker enters the safety zone. The permit identifies the equipment, the safe limits, the conditions of work, and the permit duration.
8. 8Sanction-for-test issued separately when testing requires temporary removal of an earth — the sanction is held for the test duration only and the earth is restored before the access permit resumes.
9. 9Permit cancellation only after the permit holder has confirmed in writing that all workers are clear of the safety zone and all tools and equipment have been removed.
10. 10HV-rated PPE — insulating gloves rated to working voltage class, arc-rated clothing system selected to incident energy at the switchgear panel, full hood and face shield.
11. 11Switchgear operating procedures specific to the apparatus — remote operation by stored energy or motorised actuator where the switchgear allows, local operation only where remote operation is not available, with operator at the rated standoff distance.
12. 12SF6 leak detection and ventilation in indoor substations — atmospheric monitoring during planned switchgear maintenance, evacuation of the basement before reset on a faulted SF6 breaker.
13. 13Communication discipline — confirmed two-way radio or telephone contact with all permit holders, with check-in intervals defined in the switching schedule.
14. 14Post-switching inspection of all operated equipment, with abnormal indications (overheating, oil leaks, mechanical resistance) recorded in the substation log and escalated for engineering review.

Applicable Codes of Practice

High-Risk Construction Work triggered

Worked example

An authorised switching operator at an industrial substation in Newcastle is scheduled to isolate the 11 kV feeder serving a steel mill rolling line for planned maintenance. The outage window is six hours on a Sunday morning. The operator prepares a switching schedule the day before, listing the eight switching steps, the access permit to be issued to the maintenance contractor, and the rollback if any step fails. A second authorised operator independently verifies the schedule. On the day, the operator opens the upstream 33/11 kV transformer feeder breaker, isolates the 11 kV bus, applies earths at the bus and at the rolling-line cable termination, and tests the bus dead with a calibrated HV detector. The access permit is issued to the maintenance contractor's lead electrician, who acknowledges in writing. Maintenance proceeds for four hours. On completion, the contractor signs the permit closed with confirmation that all workers and tools are clear; the operator removes the earths under permit, closes the bus and feeder breakers, and confirms the rolling line is re-energised. Total switching documentation includes the schedule, the access permit, the earthing register, and the substation log entry — all retained per network operator and WHS requirements.

Related legislation

• Work Health and Safety Act 2011 (NSW) — Sections 19, 31, 32, 46–49, 242B
• Work Health and Safety Regulation 2017 (NSW) — Sections 291 (HRCW definition), 299 (SWMS), 309 (WHS management plan)
• Electrical Safety Act 2017 (NSW) and Electrical Safety Regulation 2018 (NSW) — including authorisation requirements for HV switching
• AS 2067 — Substations and high voltage installations exceeding 1 kV a.c.
• ENA NENS 04 — National Electricity Network Safety Code (industry guideline)

Frequently asked questions