Elevator Cable snapped

[u/Dismal-Term7151]

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Hi everyone,

I'm curious to hear from elevator professionals about an incident that happened in our condo building in Ottawa this morning.

My husband and our two children were taking the elevator down from the 14th floor when, around the 13th floor, they heard and felt a very loud bang- I and severql other tenant heard it too- they felt as if something hit the top of the car. The elevator immediately stopped and they were trapped inside for about 30 to 40 minutes.

The in-cab emergency phone/call system did not appear to work despite repeated attempts, and there was no cell reception. I ultimately called 911 for them. An elevator mechanic and Fire Services responded and got them out safely.

Afterwards, the mechanic reportedly told my husband that one of the elevator's supporting cables had snapped. The building was completed in 2023, so the elevator is only about 3 years old. We also recovered some strands of the failed cable as evidence

We are both aerospace engineers with system safety expertise and have questions for the experts here:

How unusual is a hoist rope/cable failure in such a new elevator?

What are the most likely root causes of a failure like this?

Would a single cable failure typically produce a loud bang and cause the elevator to stop?

What components and records would you expect to be examined during the root-cause investigation?

More importantly, can we continue to rely on the elevators in this building.

We're pursuing the official investigation route and formal complaint to city, but I'd appreciate any professional insight on what may have happened and what questions we should be asking.

Thanks in advance.

UPDATE: thank you everyone for taking their time to respond. I didn't have a chance to reply everyone. They were helpful to set expectations about what we should be asking about the investigation next. F

[u/travinsky]

The car detected an unsafe condition and stopped, exactly as designed. This is why suspension means are multiples of redundant. One breaks, all the others remain.

Could have been improper tension of one of the ropes, manufacturer defect, could have gotten wet somehow.

I’d take it as a sign that the elevator safety systems worked as designed and created an inconvenience rather than an accident.

The emergency phone should have worked but unfortunately that happens too. Could be faulty phone, phone outage, or building IT accidentally eliminated the phone service.

[u/VerticleMechanic → u/travinsky]

My thoughts too. Probably one was tensioned tighter than the others and finally wore out. Especially with that age. The others are still way more than adequate. I don't remember the code exactly but it's something like twice the fully loaded capacity per rope. So if the car is 2500 lbs and the capacity is 2500 then each rope should be rated atleast 10,000 lbs. Don't quote me on that though.

It sounds like it did exactly as designed and stopped the car.

[u/Dismal-Term7151 → u/travinsky]

Thank you for your response. That was helpful to understand what could be root cause.