“never plug extension cords into extension cords” is probably the most common piece of electrical related advice I’ve ever heard. But if you have, say, 2 x 2m long extension cords, and you plug one into the other, why is that considered a lot more unsafe than just using a single 4 or 5 meter cord?
Does it just boil down to that extra connection creating another opportunity for the prongs to slip out and cause a spark or short circuit? Or is there something else happening there?
For that matter - why aren’t super long extension cords (50 or more meters) considered unsafe? Does that also just come down to a matter of only having 2 connections versus 4 or more on a daisy chained cord?
Followup stupid question: is whatever causes piggybacked extension cords to be considered unsafe actually that dangerous, or is it the sort of thing that gets parroted around and misconstrued/blown out of proportion? On a scale from “smoking 20 packs of cigarettes a day” to “stubbing your toe on a really heavy piece of furniture”, how dangerous would you subjectively rate daisy chaining extension cords, assuming it was only 1 hop (2 extension cords, no more), and was kept under 5 or 10 metres?
I’m sure there’s probably somebody bashing their head against a wall at these questions, but I’m not trying to be ignorant, I’m just curious. Thank you for tolerating my stupid questions
It increases the risk of electrical overload and overheating as it adds more resistance to the circuit.
Thanks for the response! Would you mind going a bit more in depth about that please? I could understand increasing the risk of overload if you were to daisychain power boards, as they add more power points to the circuit than it was designed for. But extension cords (at least in my experience) only have 2 ends - one with a single plug receptacle, and the other that plugs into a power point
Is it the actual connection between the two that adds more resistance to it? If it were the wiring, then wouldn’t that also pose a problem for longer extension cords?
In either case, what sort of resistance add are we talking about (feel free to pick random lengths of examples make it easier to explain)?
The longer the cable, the thicker (heavier gauge) it needs to be to carry the same current without burning up. One extension cord is rated to carry the current it alone is able to carry. Put two of those in series, and both of them together are able to carry less current than either one by itself. This is how fires start.
I wonder what kind of safety margin is calculated into these…
Admittedly I’ve seen some wildly different shielding or thickness in my time
This is incorrect. I need to increase gauge for voltage drop. Overloading the cable via length can only happen if I have a motor or other magnetic load at the end. A motor will try to draw it’s designed wattage regardless of voltage. A wire of a given ampacity will handle that many amps regardless of the length of the conductor. The relationship is power = voltage x current and voltage = current x resistance for single phase. The fire concern on extension cords tied together indoors is you have 100% strung that shit through a doorway or window, which is a code violation. You are going to pinch it and burn your shit down. all outdoor plugs are gfci these days and on site i can have 4 or 5 extension cords tied together. i only get 109 volts at the end but a heater is a resistive load. Doesnt matter for that application.
I don’t think what they said is actually a problem, it’s just a back-justification for the original trope. Daisy chaining them and strictly sticking to only the few appliances that would fit in one extension strip is fine. But that’s complicated to explain, it’s better to just tell people not to do it rather than expect them to understand what’s going on
A couple things that can happen…
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plugging in too many appliances over several daisy chained power strips trips the circuit breaker because too much current is being drawn
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if the country you live in has lax electrical safety standards then, yes, perhaps you can overload the daisy chain without tripping the main circuit which would lead to overheating
When the breaker trips then the fundamental issue is unlikely to be present. But to be able to push enough current to cause it to break the connection needs to have a sufficiently low resistance. If that gets too high it will never break, even if you short the cables. And that will result in a fire, because the protection does not work anymore. That is the dangerous part.
Isn’t the added cable resistance small enough to not cause issues so soon? In case you just chain a few ( < 10 ) together.
I would also like to hear an expert opinion on this. Never really made sense to me either, but it also doesn’t sound unreasonable.
I have an RV with 2x 10 gauge, 50’ extensions running power to it. I have a built-to-purpose coverat the connection point. Its fine and safe enough. Just keep slack at the connection. It cant be under pull stress.
Check the neutral pin at the pedestal and the connection. After a few months running an AC unit, it’ll be char broiled somewhere along the way.
I always thought it was to stop people from plugging too many appliances into all the outlets.
I think that would be more relevant to power boards than extension cords. Unless nomenclature is different elsewhere, extension cords here generally only have a single plug. Although there are usually warnings to not run things like clothes dryers or portable stovetops through an extension cord because it can apparently melt the cable. Truthfully, I don’t entirely get that either, as I would’ve assumed they’d be built to the same standard as internal wiring
Ah, no worries! I’m not sure if it’s even universally agreed upon across native English speakers. Where I’m from though, a powerboard (or power strip in other parts of the world) has one plug that then leads on to usually 4 or more additional power points/sockets. An extension cord on the other hand usually only allows a single device be connected to it (whether that’s another extension cord or something else)
Meanwhile landlords: "one 50 year old outlet should be enough for two bedrooms right?*
This, along with hotels that hide their only power point behind the bed but have 50 bloody phone jacks, are my pet peeves. But it kinda makes sense when you consider they were mostly built before the days of having a ton of devices in the bedroom. A lamp and alarm clock, maybe a TV if you’re well off, would’ve been perfectly fine for a lot of people
The absolute worst is when the Word Documents are stashed away in some random drawer. Or when you find an Excel spreadsheet under the mattress!
I really wish my autocorrect would stop doing that. I can count on one hand the amount of times I’ve actually wanted to write “PowerPoint”. I couldn’t even count on 10 hands the amount of times it’s assumed I’m some kind of idiot that doesn’t know “PowerPoint” is a single word when I type “power point”
I once read a theory on an electricians forum about how the USA electrical code’s mandated maximum distance between adjacent outlets on a wall, coupled with the typical bedroom layout, as well as home builders trying to be as cheap as possible, led to only a single outlet being placed directly in the middle of the longest wall. This is also the most logical position for a bed, so the theory is that the bed pressing against the outlet over time was a contributing factor to electrical-related house fires.
I cannot find where I read that originally, and certainly the granularity of nationally-reported fire data is not sufficient to prove that theory. And while the electrical code’s distance requirements haven’t changed, more homes will now put enough outlets so the only one isn’t behind the bed.
Years ago, I used to play live music. We played in a lot of shitty dive bars. Thinking back on all the ancient decrepit plugs we used to power our instruments, amplifiers, and stage lights with…it’s a miracle we never started a fire. Nightmare fuel now that I’m older and a little bit wiser.
