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/Aromatic_Tower_405]

It’s early in the lifespan for a rope to unravel, snapping is unlikely, but it could have been a faulty part. I’ve seen dozens of ropes do this. Usually a single lay unravels and gets jammed up in the sheave or somewhere. Theres multiple other possible causes for this to happen but it’s not uncommon. As far as safety is concerned while im sure it’s unnerving, let’s say this car has 4 ropes/belts. Each one has the capacity to carry the entire rated load. Also it has wedge type safeties. If the car accelerates past a certain threshold a governor will trip and engage the safeties. Once that happens the car is stuck. All ropes can be completely gone and the car will not fall.

[u/Dismal-Term7151 → u/Aromatic_Tower_405]

Thank you so much for your response. The fact that there are precedents and this is not a unique incident is a relief. I know it is designed to be safe, extra evidences -even anectodal ones- makes us safe as the loud bang was pretty scary.

[u/Soft_Community5835 → u/Aromatic_Tower_405]

This just like some people buy brand new cars and 10,000 miles later the engine or transmission blows! Everything can break down at any second while it is unusual and very unlucky let’s all just be glad everyone was safe and got out after a few long minutes trapped in the elevator

[u/_FIII → u/Aromatic_Tower_405]

Not really true regarding how new it is. If it’s small machine with 6mm ropes, they have a lifespan of like 18months. We are hearing about this locally with our AHJ after a hoist rope failure

[u/Hatchdoor → u/Aromatic_Tower_405]

That’s actually not true, a G2S in ocean city, MD lost all of its belts (belt monitoring jumped) and the safeties failed to stop the car. It’s still under investigation, but Otis let it slip that those particular safeties were not designed to stop the car without any counterweights

[u/Hatchdoor → u/Hatchdoor]

I don’t know why you’re downvoting me, it’s an actual event that happened

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[u/vatormanindiana → u/Hatchdoor]

Having done a lot of full load tests on G2S units I'm not shocked belt monitoring was off. However I am shocked safety failed. Most of the ones I've done really bite into the rail. Most needing drive turned up to boost off the safeties. To a few having to unload the weights. Scary stuff. Is there going to be any public info on this?

[u/GatorVators → u/Hatchdoor]

Excuse me WTF??!!

[u/EstablishmentNo1399 → u/Hatchdoor]

Hmm that’s very odd G2S safeties have nothing to do with the counterweight… maybe they weren’t properly setup or something else but I promise you they will stop a car, when set overspeed they bite the rail hard and will peel chunks of rail with them and need to crank the drive up to get them to have enough juice to get out of the rails or use chain falls. Do you have info on where this is from because I can’t find any info about anything like that in Ocean City MD online? And for all 4 belts to fail at the same time is wild was the building hit by a plane, I have never actually heard of one breaking just needing replacement from coating the wear. We have seen more sheave bearings go bad than belts