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I don't know if the better question should be "why does, for example UK, require earth wires to be covered in a yellow sleeve in junction boxes", or should it be, "why does, for example USA, NOT require it and why don't electricians do it as a best practice?" ... but it seems like a fairly fundamental idea that is either an excellent and safe one, or an unnecessary one, and I would expect at some point in history there would be consistency. What's behind this?

Machavity
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jay613
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  • Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/140139/discussion-on-question-by-jay613-why-is-it-required-in-some-countries-to-sleeve). – Michael Karas Oct 25 '22 at 23:58
  • @MichaelKaras respectully, and with thanks for your moderation work, that was a bad move. All the noisy comments, about 20, had already been *deleted*. There were only 5 or 6 left and they were helping to better understand the question and had the potential to provoke answers. Especially the last couple. They were the reason comments exist. – jay613 Oct 26 '22 at 01:23

2 Answers2

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On one hand it improves safety very marginally... on the other hand it escalates time and cost. Simple as that. In marginal-benefit cases like this, every country makes that call in their own way.

The builders have a very strong lobby within NFPA, which is why improvements are highly valued which let the builder work faster, like backstabs, wire nuts or plug-on-neutral breakers. A proposal to amend NEC to require the sleeves would need to be supported by a body of evidence documenting fires which the bare grounds have started. Since NFPA is, after all, the National Fire Protection Association* and gets fire reports from most fire chiefs, they have that data.

Note also that the UK line-ground voltage is twice North American voltage, since we actually do the center-grounding that the UK only does on construction sites. As such, open-air arcing between a live terminal and a nearby bare ground may be more of a risk in the 5-continent system.

* Weirdly you'd expect them to be the National Fire Prevention Association. The National Fire Protection Association should be teaching artillery crews how to deal with counter-battery fires, and the fine art of "shoot and scoot".

Harper - Reinstate Monica
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  • Is it that the reson why they invented the AFCI – asinine Oct 23 '22 at 22:11
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    Makes sense. I don't know specifics regarding UK electrical code but there is a stronger tendency in some countries (UK, Germany, Switzerland at least) for standards to be guided by lofty engineering ideals, without so many lobbies tying it back to their profit. Hence for example the standard UK appliance plug, with more engineering in it than a Chevy Cruz. Compare that to the standard USA single-insulated two-wire lamp cord with a two-prong plug that falls out of the socket if you look at it the wrong way. I guess insurance data says that's not what's killing people so why fix it. – jay613 Oct 24 '22 at 13:59
  • I, generally, agree with your reasoning, @jay613. While plugs falling out of sockets is annoying, it's a reasonably simple fix to replace _one_ socket, rather than every. single. socket. in. the. country. with a highly engineered alternative that won't allow that to happen. It's also a reasonably _infrequent_ problem that _isn't_ killing lots of people. – FreeMan Oct 24 '22 at 14:48
  • You'd think by now that things like backstabs are well documented enough as a fire hazard that they'd be forced to stop using (or even making) them. I think it's among the most frequently quoted no-no's on this site at least... – Darrel Hoffman Oct 24 '22 at 18:14
  • I think fire "protection" is a reasonable wording. The best way to protect people from fires is to prevent them, but people are going to be people. Theres only so much prevention you can do with building codes. People will catch things on fire in spectacular ways, so having systems to protect people is the next safety step to take if you cant prevent them. – JMac Oct 24 '22 at 20:19
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    @JMac: I think the verbiage problem is that you should protect people from fires, not protect fires. – Ben Voigt Oct 24 '22 at 21:03
  • Harper what do you think of P2000 theory in Comment to Question ... that the prevalence of different earthing systems, or perhaps the history of those, in different countries creates different appetites for this practice? – jay613 Oct 25 '22 at 21:48
  • Another thing about backstabs is that they only work with 14GAUGE wire, so why bother if other gauges can't be backstabbed – Frank O'Donnell Oct 27 '22 at 11:27
  • Accepted answer on the theory that mandates for marginal or undemonstrated safety improvements are met with greater resistance in the USA than UK and some European countries if they increase cost or complexity of construction. – jay613 Jan 25 '23 at 16:44
  • @jay613 But counterpoint, when safety improvements *are* demonstrated, we go kowabunga. Ask anyone who has paid for AFCIs, 5mA GFCIs (which must necessarily be per-circuit), outdoor disconnects, surge suppressor, 2 ground rods per structure (rather than hanging it on a supplied PEN), separate ground and neutral on all feeders (even from a "meter at a pole" where it seems stupid to me)... Europe still does none of that, I note. (though maybe localities do it, as our localities and states adopt NEC, or not). – Harper - Reinstate Monica Jan 25 '23 at 21:18
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Seems common sense to me to sleeve any bare wires jumbled about in a box along with live conductors and cables. Especially since you can't be 100% sure what's going on when you push the covers back.

I regularly see electrical boxes stuffed to the brim with 'added' cables after 'improvements' and you can barely force the cover back on. This blind pushing could in theory push a bare cable somewhere it's not supposed to be.

I often see bare earth wires here in Norway, but as I'm British, they always get a bit of sleeving from me before the cover goes back on. I also often see those wire nuts which I always find amazing, like something temporary a kid would do... WAGO is the only way for me I'm afraid.

handyman
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