Ausgrid have issued a ASP Safety alert 3rd January 2018
Where installing or altering contestable connection assets within Ausgrid’s network area, ASP’s must ensure that those assets have been correctly tested in accordance to network standard requirements prior to electrification
Whilst performing pre-commissioning testing on a new low voltage (LV) network distributor (NS161), an ASP1 failed to identify low insulation resistances (IR) between cable phases. Failure to identify the low IR readings resulted in a short circuit condition being present during electrification.
The ASP1 works included inspection of cable terminations and testing procedures (NS230/NS161) required to facilitate electrification of a new kiosk substation and associated LV distributors. Works were being performed as part of the pre-commissioning process where the assets had been constructed under an equipping permit.
Upon completion of the testing procedures an ASP1 worker signed off the equipping permit for cancelation.
LV distributor cables were installed between new kiosk substation and two low voltage pillars. During cable termination works the ASP1 installed LV shorts within one of the pillars to correctly identify individual phase terminations. The ASP1 failed to remove LV shorts upon completion of termination works.
On the day of electrification whilst IR cable tests were performed, the ASP1 failed to correctly identify a low phase to phase reading which was present due to installation of the LV shorts. Upon completion of precommissioning works the ASP1 worker signed off the Equipping permit ready for cancellation.
Failure to remove the low voltage short and correctly identify cable test results were a contributing factor.
Recommendation / Actions
This incident could have resulted in more significant impacts to the persons involved. In the interest of your employees ASP’s are requested to;
- Remind all staff of the importance to correctly perform testing procedures prior to signing off equipping permits for new or altered contestable connection works.
- Review existing SWMS to ensure cable testing procedures have been adequately addressed.