Hi everyone,
I’m seeking insight into a mass electrical outage that occurred at my commercial premises, a hot yoga studio located in Australia—on May 28, 2025. The incident resulted in a complete loss of power to my unit and significant damage to equipment. I’d greatly appreciate expert perspectives on what might have caused the issue and whether liability could fall on a builder working on the roof at the time.
Background:
What I’m Seeking Advice On:
I’m seeking insight into a mass electrical outage that occurred at my commercial premises, a hot yoga studio located in Australia—on May 28, 2025. The incident resulted in a complete loss of power to my unit and significant damage to equipment. I’d greatly appreciate expert perspectives on what might have caused the issue and whether liability could fall on a builder working on the roof at the time.
Background:
- My building is a single-level commercial complex with 7 units, all connected to a main switchboard at the opposite end of the property from my unit.
- I have one main panel and one subpanel inside my unit.
- The subpanel feeds 24 Far-Infrared heating panels, wired as 2 panels per circuit (12 circuits total).
- All equipment was functioning normally in the early morning (heating panels, AC, lights, computer).
- Around mid-morning, my entire unit suddenly lost power—every circuit tripped, including the main switch at the external building switchboard.
- At the same time, roofing contractors were replacing the metal roof across the building. They claimed to be working only at the opposite end of the building, focusing on air conditioners.
- My staff immediately consulted the builder, who began flicking breakers at both my internal panels. When nothing restored power, he brought in two workers and later accessed the main external switchboard.
- Shortly after they left, power returned to lights only. Heating panels and several devices remained non-functional. The builder had energized all the switches in my main panel and sub-panel. He then went down to the other end of the building and energized the main power switch which was in the off position (no one knows why it was off).
- All 15 sub-circuits were tested: 12 failed insulation resistance tests, with faults between active/earth and neutral/earth.
- 11 of those 12 faulty circuits were connected to the heating panels.
- A total of 23 heating panels were damaged, along with a computer and 2 LED panels.
- They suspect a massive inrush current occurred when the builder reset the main breaker without isolating any downstream circuits.
- The inrush current estimate was 188A (24 x 1800W panels), which likely exceeded the breaker’s rating and triggered the damage.
- They concluded the most probable cause was improper energizing after an initial trip—everything was left ON during reset.
- What would cause every circuit in a unit to trip simultaneously—including the external main switch—if not external grid issues?
- Could roofing work (e.g., screws through beams or AC service) feasibly damage internal wiring or cause a fault?
- Is it reasonable to suspect the builder caused the fault through improper handling of electrical infrastructure (e.g., flipping breakers without isolation)?
- What further tests or investigations would you recommend to conclusively determine the root cause?
- Any insights on how to support a potential liability claim (e.g., evidence, legal steps, typical builder responsibilities)?
- Is there a test that can be performed on the main power feed line from the main switch board at the other end of the building to my unit that could detect if the cable was “screwed” into or damaged and consequently had the screw removed leaving a damaged cable which is not currently shorting?
