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Comment by generatorguy | Hacker News Reader

I’m seriously impressed that the distance between the source conductor, command conductors, and presumably return conductors is considered.

As a power systems and controls engineer we make Some effort to separate wires carrying different voltages eg 24v and 480v, but positive and negative run in the same cables or conductors in the same raceway all the time with nary a second thought.

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Those distances haven't been considered until real electrical shorts happened, safety standards are written in blood:

> The regulation was introduced in 2009 following study of two fatal crashes: TWA 800 in 1996, in which an electrical short is believed to have caused a spark in the fuel tank and an explosion; and Swissair 111 in 1998, when an electrical short caused a fire in the cockpit.

The FAA and its sister agencies around the globe are very good at root-cause analysis. Where a single fault could cost many lives, there's strong incentive to follow any failure all the way back.

I'm guessing that your systems don't experience anything like airplane levels of vibration, or have anything like airplane numbers of fatalities if the controls fail, yeah?

In the US, the NTSB does root-cause analysis and makes recommendations to the FAA.

There’s a separation of concerns. The NTSB is solely concerned with finding out what happened. The FBI handles criminal investigations. The FAA is concerned with running air traffic control, regulations, and research.

they are turbine generators in hydro electric power plants - they are live buildings; the floor and walls are resisting all of the torque from the generators and the forces exerted by the water flowing through the building, and the machines are vibrating at 1 mm/s velocity or about 4/1000" displacement. So it isn't completely stationary, everything is just kind of humming and rumbling - unless there is a short circuit out on the power system and then massive forces are exerted on the generator and power conductors, or if the machine becomes disconnected from the power system and has 10 MW coming in and 0 MW going out it tends to speed up quite rapidly and shake a bit more - but for the most part I can't imagine any conductors wearing through their insulation, ever. No wires are ever exposed to sharp edges.

Is there something to be said or considered for the fact that the wires are in a dynamic system that might vibrate or chafe away insulation? I feel like that's a big part of the consideration in the separation criteria here, but I'm not an aviation or electrical expert at all.

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