this post was submitted on 29 Jan 2026
451 points (99.6% liked)
pics
26604 readers
336 users here now
Rules:
1.. Please mark original photos with [OC] in the title if you're the photographer
2..Pictures containing a politician from any country or planet are prohibited, this is a community voted on rule.
3.. Image must be a photograph, no AI or digital art.
4.. No NSFW/Cosplay/Spam/Trolling images.
5.. Be civil. No racism or bigotry.
Photo of the Week Rule(s):
1.. On Fridays, the most upvoted original, marked [OC], photo posted between Friday and Thursday will be the next week's banner and featured photo.
2.. The weekly photos will be saved for an end of the year run off.
Instance-wide rules always apply. https://mastodon.world/about
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
It's about IO not compute. The controllers for plants like this aren't very complicated but they can have many thousands of signals going to/from them. For a ~500MW plant I'd expect somewhere between 2-5k IO, more if it's nicely automated.
Automation engineer, have worked on power plants.
Who would win? An over-stuffed cable tray, or 4 twisty bois?
What? The IO is digital inputs and outputs, analog inputs and outputs.
Then there's power distribution and 24v DC device power (or 120v depending on application and often age), relays, contactors, timers, VFDs, etc. This is what the world runs on. Networking cables like that Ethernet are still part of it but a pretty small part. They just get plugged into all the PLC racks and any other device that needs it. Some of what I described can be replaced with automation and code, but only the very old legacy devices a lot of these old plants and mills still have around because they're still functional..
This is the only comment which mentions PLCs, and wired PLCs are what industries used for decades.
My point (if you can call it that) is that you can have remote racks and cut the total footage of wire by 75%
But then you have many racks that could fail, any one of which taking the system out. So you add redundancies and now you have a small "server room" in each section of the building that needs to be clean enough to inspect devices without getting sut or coal dust on them.
Engineering is about tradeoffs.
Sometimes that means sticking enough RAM in a missile that runes out of fuel first and sometimes you run a lot of cables, but make up for it in reliability and easier maintenance.
Yeah, exactly. You definitely save some copper by running ethernet to remote racks but by raw wire count it's not reduced much. There's a LOT of modern plants (power and manufacturing plants) that have way more wiring than this in a photo
I mean nowadays yes but the pic has some old relays in it, I'm fairly sure the DCS/PLC is not ethernet if there even is one
Why so many? Is it a relatively small set of signals multiplied over multiple boilers or something, or is each line really doing something different, or what?
Are modern plants similarly full of wires, or have they streamlined it (e.g. by multiplexing a bunch of signals as packet data on a single networking cable)?
Um, I mean the boiler(s) itself are a small part of it. It's all the other stuff. I am not a coal expert by any stretch, but if you think of the signals required just to convey coal, probably dozens or more of drives with run/stop/various errors/temperature/current/voltage/perhaps VF, plus all the sensors you need to use motors like that with (presumably bucket conveyors?) like slip, like explosion disk detection from dust. Not like all of those have to be present, but every step has so many signals.
Plus then you've got a steam turbine and a switchyard, plus all the plant utilities like process heating and cooling water, compressed air, steam turbine makeup water, etc
Nowadays you do IO to remote racks that are close to devices (like valves/motors/etc) then use Ethernet to make it go further. Pre ethernet there were typically proprietary cables for the same, but thankfully that's a thing of the past
But something like I mentioned with a motor drive having all those signals, yeah it's typically just an Ethernet cable + power + estop (usually hardwired still). So maybe 40-50 wires down to 5-8
Whether its a power boiler or a recovery boiler there are a huge number of sensors and actuators needed to monitor and adjust. Just the pressure systems at the various points inside the boiler tubes. Required miles and miles of copper cable. There is also a huge number sensors and actuators in the fire box from the fuel feed to the exhaust and anti pollution systems.
Then you move on to the turbine section and you have more wiring for that.
I once saw the aftermath of a single oil sensor failing and not going to zero. It hung and didn't alarm. The the babbit bearings on the turbine side seized. The whole place nearly melted down until the engineer on site managed to get the boiler shutdown with very minimal damage to the boiler. They fired him the next day for the maintenance miss and they had to rebuild the whole turbine because the blades got wet.
Power boilers if they lose water they will melt from the hanger to bottom. I've seen the aftermath of that as well. So the old legacy stuff is here to stay until it stops working.
Nukes were that times ten. Multiple sensors for any given system plus stand by emergency systems all leading to control room. Inside the containment vessel there are cable trays everywhere on every level. The support equipment outside the containment vessel were no different. It is unlikely most of that will can ever be replaced. Many of these systems take a decade or more to slights retrofit because with a nuke you can't really make a mistake.
I sat in on multiple meetings because a pump housing mounting bolts were supposed to be left handed threads but were right handed instead. It took them over a week to decide if it was okay that way. Engineering office guys were trying really hard to not to have to submit all the paperwork to get the prints changed after nearly twenty years in service. It would have been very costly in time and materials to remove the studs in the floor and replace and repour the floor section so they kept the right handed threads. This should give you some idea how hesitant they are to change anything in a nuke. I can only hope in the nearly thirty years since I did those kinds of shutdowns they have replaced some of it.
Yeah modern stuff still has lots of wires. An automated valve may have 4 or 5 wires - open command, open feedback, closed feedback and 0V.
A switch to show something is open or closed will have two wires.
You can put a lot of that stuff on a fieldbus but that is often trading lower install costs for higher ongoing costs and more downtime.
The real hero is in the comments.