Protection of cable through metallic structures
This advisory note outlines common non-compliances found when Building Commission NSW inspects electrical installations. It provides guidance to help licensed electricians and contractors carry out safe and compliant installations.
| Note | 5/2023 |
| Last updated | August 2025 |
| For | Licensees / Contractors / the Electrical Industry |
| Issued by | Building Commission NSW – Electrical Inspections Team |
| Scope | Applies to all of NSW |
Purpose
The purpose of this advisory note is to inform industry of some common non-compliances found when Building Commission NSW inspectors conduct inspections of electrical installations.
Reference
AS/NZS 3000:2018 Wiring Rules
What is the non-compliance?
The installed wiring system was passing through a metallic structure unprotected from the sharp metal edge of the in the structure
Clause 3.9.3.1 of AS/NZS 3000 Wiring Rules states, Where a wiring system consisting of sheathed cables is installed through metallic structural members, any aperture through which the cable passes shall be bushed or shaped to minimize abrasion of the cable. Where likely to be disturbed, the cable shall be fixed in position at a point adjacent to the aperture.
How to comply
As per the requirements of AS/NZS 3000 Wiring Rules:
Wherever sheathed cables are passing through a metallic structure, like steel framing, switchboard entries or metal enclosure or cable tray, the entry hole shall be bushed or shaped to protect the cable from damage to the sheath of the cables and potentially exposing a live conductor.
As per AS/NZS 3000:2018 3.3.1, Wiring systems shall be able to operate safely and shall function properly in the conditions to which they are likely to be exposed at the point of installation. It is important to remember that the protection of cabling must happen at installation in order to prevent unwanted damage during the install/construction stage of the job.
What we are finding
The requirement to have the cable protected from sharp metal edges is a common non-compliance in domestic and commercial setting found by our inspector.
In this example the switchboard supply mains were passing over the cut edge of a cable tray lid exposing the potential for damage to the insulation of high current capacity supply.
The edges of the tray how now been covered by a durable material that will prevent any potential damage to the live cables installed on the cable tray.
In this example the supply cable to a gas hot water service is passing through a cable entry unprotected, already causing damage to the insulation of the installed cable.
The cable for this installation has been protected by installing the cable with a corrugated conduit to protect the cable damaged thought the construction phase of the project.
Contact Electrical Compliance Team
This advisory note has been approved for issue by the Electrical Compliance Team.
Information contained within this document is current at the time it was last updated and refers to codes and standards current at the time of writing.
Building Commission NSW disclaims any liability (including for negligence) to any person in respect of anything done, or not done, by that person in whole or partial reliance on any of the information in this advisory note.
For more information, please email: electricalcompliance@customerservice.nsw.gov.au