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OriginalSuggestion87 t1_j237orz wrote

Reply to comment by Apotropaic_Sphinx in 120v Extension Cord with USB outlets by HardSn0wCrash

An outlet is not intended to be supplied with stranded wire. The terminals are not the right type for that kind of connection.

Add to that the questionable "strain relief" used and these things are just breaker testers waiting to happen.

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roobinsteen t1_j25bdeq wrote

You are incorrect. Stranded wire is absolutely fine to use with receptacles. The majority of wire run through conduit (think commercial electrical applications) is all stranded, not solid. The only issue is putting stranded and solid under the same terminal (such as a backwire plate, which can accept two conductors), but that isn't happening here.

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horsemagicians t1_j25e8bl wrote

>The majority of wire run through conduit (think commercial electrical applications) is all stranded, not solid.

As a commercial electrician I can promise you this absolutely isn’t true. 99% of the time it is solid. Far easier to terminate solid in a panel then stranded. The only time stranded is really used is when you have to because the wire size is 8awg or larger and it’s only stranded at that point.

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entropy512 t1_j25ps95 wrote

I've been told (I have yet to confirm) that at least in the EU, when terminating stranded into a screw terminal, ferrules are required.

(Ferrules are wonderful in this regard - they let you get the flexibility of stranded wire, but as far as termination is concerned, stranded with a ferrule crimped on it may as well be solid.)

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roobinsteen t1_j25esvw wrote

Fair enough, I defer to you. Oddly though, electricians I know (small residential contractor here) have told me the exact opposite--they often use stranded in conduit because it's easier to pull. Either way, as I'm sure you know, stranded is acceptable to use on receptacles in most cases. OP used the backwire terminal clamps, which is OK for stranded.

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OriginalSuggestion87 t1_j27t4ha wrote

Not only have I never experienced "all stranded" in commercial wiring, I would refuse to work with an electrician who ever tried to pass that off.

That people (read: corner-cutting contractors) do it doesn't change the fact that it is not the intended purpose.

An outlet was not designed to be supplied by a stranded wire, especially stranded wire subject to constant flexing and strain. Full stop.

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roobinsteen t1_j29ewnm wrote

>An outlet was not designed to be supplied by a stranded wire

This is just factually incorrect. Outlets are 100% UL listed for use with both stranded and solid wire, with the only exception being the push/backstab terminals, which must be solid wire. This isn't a matter of opinion. Have a look at this product spec doc from LEVITON:

https://www.leviton.com/en/docs/L-300_B_StraightBladeDevices_2015_Q2j.pdf

all of their receptacles are listed for use with stranded wire in both side and back wiring applications (to be clear, back wiring is using the clamps under the terminals, not back stabbing).

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OriginalSuggestion87 t1_j2b01hl wrote

Is your position that stranded Romex or MC is the same product as stranded appliance or lamp cord as used in the OP's Instructable simply because they're both "stranded?" Is your position also that the UL listing covers an application that will subject the terminations to strain or the supply cable to regular flexing?

I'm willing to bet "homemade power strip" isn't a covered use case under the UL listing, either.

I'm in awe of the mental gymnastics involved in twisting this DIwhy into "100% UL listed" territory because the word "stranded" can apply to multiple products.

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roobinsteen t1_j2b80i6 wrote

>An outlet was not designed to be supplied by a stranded wire

That's what you said, and that's just a factually incorrect statement, which is what I was responding to. It is perfectly safe, fairly common, and UL approved to wire an outlet or switch with stranded wire using the appropriate terminals.

I agree with you that OP's little invention would obviously not be a UL listed device, but again, you said that under no circumstances can stranded wire feed an outlet, which is wrong. Now....despite OP having created something that wouldn't be UL acceptable...it's likely not unsafe as long as they did a good job making the mechanical connections. I myself have a "homemade" extension cord feeding a double duplex outlet box. Made it using a 12awg extension cord and a foursquare Handybox. Is that UL listed? No, but I have beat the ever loving shit out of it on jobsites for a long time and it's fine. Many tradespeople have similar homemade extension cord+boxes and beat the shit out them as well.

My overall point is this is almost certainly not an unsafe device to use, but if I were OP i wouldn't have posted it online to show off, because of the obvious and predictable way in which people would freak out about it.

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