Wikipedia:Reference desk/Archives/Science/2021 November 19

= November 19 =

How can a circuit breaker allow me to reset ?
A circuit breaker in my home was triggered because I turned on the multiple high amp devices how can I am able to reset it without turning off the devices? Rizosome (talk) 01:29, 19 November 2021 (UTC)
 * Maybe it's not "idiot-proof". ←Baseball Bugs What's up, Doc? carrots→ 03:45, 19 November 2021 (UTC)
 * If I try to understand your question. If you turn off your circuit breaker and turn it back on, vs. reset your circuit breaker without turning it off, of what difference is that? 2601:249:8200:A640:BC94:25D0:A27B:E49B (talk) 04:21, 19 November 2021 (UTC).

"Idiot-proof"? I am asking how circuit breakers allow me to reset without turning off high amp devices? Rizosome (talk) 07:47, 19 November 2021 (UTC)
 * If the circuit breaker trips, devices on it are likely to shut down. Are you saying they don't? ←Baseball Bugs What's up, Doc? carrots→ 07:51, 19 November 2021 (UTC)
 * It is very obvious that they are asking about putting the switches in the "off" position before resetting the breaker, not about devices magically being powered. Tigraan Click here for my talk page ("private" contact) 10:00, 19 November 2021 (UTC)
 * The only way to do that would be to have your devices on different circuits. Be aware that some devices could be damaged if they are not turned on using the switch on the actual device.--Shantavira|feed me 09:29, 19 November 2021 (UTC)
 * Are you concerned about the inrush current tripping the breaker again? The only way to avoid this is either turn the devices off before the breaker is turned on, and then slowly turn the devices back on. Or permanently put the devices on a different breaker. LongHairedFop (talk) 09:39, 19 November 2021 (UTC)


 * To answer the OP seriously, the answer is you probably cannot. What usually trips a circuit breaker is that there is an excess of current on that circuit.  If you make no changes to the circuit, such as trying to "reset it without turning off the devices", the breaker will likely just trip again immediately.  If you are tripping a breaker, the best solution is to remove one or several of the high-amperage devices from the circuit that was being tripped, and plug them in on a different circuit.  -- Jayron 32 17:03, 19 November 2021 (UTC)


 * There are a lot of situations where a marginal overload might not immediately trip a breaker. Appliances may require slightly more or less current depending on what they're doing at that moment. So if you're right on that line, you might be going above and below the breaker's rating without actually turning anything on and off. Besides that, depending on its technology, the breaker itself may take a few minutes to trip if it's right on the edge between good and too-much-current. This is actually considered a feature of home circuit breakers and is deliberately designed in.
 * Check out the illustration (and description) at Circuit_breaker. It actually has separate fast and slow mechanisms for very over-current and slightly over-current situations.  ApLundell (talk) 20:33, 19 November 2021 (UTC)
 * The most common reason that a circuit breaker trips, in my home, is that a light bulb fails. The circuit breakers are in a single unit but these are clearly marked as being for light circuits or for the ring mains/cooker socket and so on. In the case of a bulb failing, it isn't going to light up again when switched on, so I just reactivate the circuit and go look for the bulb that's now off and needs changing. For any other case, I'd advise "safety first" and always switch off the high-current devices individually before resetting the circuit breaker. Mike Turnbull (talk) 22:17, 19 November 2021 (UTC)
 * It's pretty rare for a bad light bulb to trip a breaker. Personally, I've never even seen it happen. If that happens regularly you may have some kind of problem. ApLundell (talk) 00:52, 20 November 2021 (UTC)
 * Anecdote: in the days just after the Second Great Northeast Blackout, the power supply was considered unstable at first and we were told to minimize usage during peak-usage hours. One night at 10 pm, I started watching a TV show, with the lights and air-conditioning off.  At the first commercial break, I walked over to my computer terminal and checked the power authority's web site to confirm that the evening usage peak was over, which it was.  I then turned on the A/C and the light switch nearest me.  We still had incandescent lights in those days and that switch controlled two 150-watt bulbs.  There was a momentary flash, and then the room was dark again &mdash; no lights and no TV either!  I panicked for a few seconds: had I really triggered a new blackout?  Then I noticed the terminal was still working, and realized the lights and the TV were on the same circuit as each other.  One of the 150 W bulbs had blown when turned on, as they would so often do, but in such a way that the broken piece of filament caused a short-circuit within the bulb, which tripped the breaker.  I wrote at the time: "I've probably experienced this three or four times in my life... But it's the first time when the lights I was switching on were going to be the only ones that were on!  That was dramatic!" --184.144.99.241 (talk) 03:34, 20 November 2021 (UTC)

This sentence solved me problem: If you make no changes to the circuit, such as trying to "reset it without turning off the devices", the breaker will likely just trip again immediately. Rizosome (talk) 03:40, 20 November 2021 (UTC)
 * There are scenarios where resetting a circuit breaker does not automatically trip again. Some devices draw power only at certain times.  A fridge or a freezer uses power only when their insides get too warm and then turn on their compressors.  An oven or a water heater heats for a while, then turns off for a while, and heats again when its temperature hits a low threshold.  A computer might go into high power use mode when drawing a particularly complex web page or game screen, and have a low current draw at a reboot.  Some devices go to an off state when rebooted - e.g. you wouldn't want a scroll saw to return to full power automatically after a power outage.  Some devices default to an off state because they have no memory of what they were doing - televisions, washing machines, etc.
 * If you have a bunch of such devices, you could get unlucky and have all of them go into power use mode simultaneously. When you re-engage the circuit breaker, some of the devices think "naah, I'm fine, no need to turn on right now" and the total power draw is below the breaker trip threshold.  It's not that you change the circuit, it's that the devices in the circuit do the changing for you. 85.76.71.156 (talk) 16:14, 20 November 2021 (UTC)

One evening there was an almighty bang, the lights went out and I felt something hot dripping onto my head. I soon found out that the light bulb had exploded. I changed it, reset the fuse and everything was dandy. 77.103.9.55 (talk) 12:38, 21 November 2021 (UTC)
 * Light bulbs drip? And you're sleeping under one? ←Baseball Bugs What's up, Doc? carrots→ 15:48, 21 November 2021 (UTC)

Spiroshell
I'm reading a trashy spy novel set in the 1990s UK. One of the characters suffers respiratory arrest and is put in a Spiroshell to recover. Web search finds that a Spiroshell is a breathing assistance apparatus, basically an iron lung for the upper body only. But there are remarkably few references online. Has anyone heard of this thing? By the 1990s, wouldn't they use a ventilator instead? (Late 1990s I think, since the characters have mobile phones). If you think it's appropriate, maybe make a redirect from Spiroshell to iron lung? Thanks. 2602:24A:DE47:B8E0:1B43:29FD:A863:33CA (talk) 11:44, 19 November 2021 (UTC)
 * I guess that novel might be this one (a mention is on that page). It's also known as a "Curiass ventilator"; and "Shell ventilator". see e.g., . (p. 454),, . Wtmitchell  (talk) (earlier Boracay Bill) 12:22, 19 November 2021 (UTC)
 * Whereas "cuirass" or "shell" refer to the type of respirator, closely fitted to the upper body, "Spiroshell" looks like a trade name, formed from "re spir ator" + "- o -" + " shell ". I found two non-fictional uses in medical publications, next to those in Forfeit, enough to make clear this is not a fictional trade name. Neither was particularly informative; both appeared to assume that the readership was familiar with the term. --Lambiam 15:09, 19 November 2021 (UTC)
 * More about cuirass ventilators here. Apparently they give greater control than other methods and "maintain and redevelop the respiratory muscles which may weaken with respiratory failure and mechanical ventilation, this allows patients to be weaned from a ventilator". Alansplodge (talk) 15:41, 19 November 2021 (UTC)
 * Yeah I also found the reference to Forfeit, but the novel I'm reading is much different. (I'm not recommending it, it's entertaining enough to keep reading if you're already into the genre, but it's absurdly slow paced and has other serious weaknesses.) Thanks for the find about cuirass respirators.  Any idea if they are in widespread use?  I had never heard of one before, and the iron lung article indicates that iron lungs are near obsolete now.  I guess Spiroshells are much less invasive than ventilators.  The person can talk, read, etc. while enclosed in one.  So those are significant advantages. 2602:24A:DE47:B8E0:1B43:29FD:A863:33CA (talk) 21:10, 19 November 2021 (UTC)=
 * I'm no expert but I've been sort-of following this discussion out of curiosity. See change over time in this graph and the table in . Also, the Mechanical ventilation has related info. Wtmitchell (talk) (earlier Boracay Bill) 21:41, 19 November 2021 (UTC)
 * Oddly, we had redirects from Biphasic cuirass ventilation and Biphasic Cuirass Ventilation to iron lung but not one from the term that people would be more likely to search, namely cuirass ventilator. I'm just about to create that redirect. Mike Turnbull (talk) 22:01, 19 November 2021 (UTC)
 * Isn't a more appropriate redirect target?  --Lambiam 15:35, 20 November 2021 (UTC)
 * Yes, possibly. I chose iron lung only because that's where the "biphasics" went. I wasn't aware of Negative pressure ventilator: both articles mention the cuirass and the iron lung article has the other as a "See also". Iron lung is marked as the "main article" within the section on "Types of NPV" and in that article the cuirass has its own brief subsection. I'm no expert on the topic, so I don't know the best way forward. By all means alter the redirect if you think that's best. Mike Turnbull (talk) 18:27, 20 November 2021 (UTC)
 * Checking again, Biphasic Cuirass Ventilation redirects to Mechanical ventilation, while Biphasic cuirass ventilation is the redirect that goes to iron lung (in a section that no longer exists). Clearly, all this needs to be tidied up by a subject expert! Mike Turnbull (talk) 20:26, 20 November 2021 (UTC)
 * Perhaps a better link might be Negative pressure ventilator which actually mentions cuirass ventilators. I have left a note at Wikipedia_talk:WikiProject_Medicine in the hope that some knowledgeable help will be forthcoming. Alansplodge (talk) 09:31, 21 November 2021 (UTC)