Author Topic: Electrical Safety Aspects That Have Not Improved Over Time  (Read 1676 times)
flyoffacliff
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Electrical Safety Aspects That Have Not Improved Over Time « on: September 29, 2022, 12:00:54 AM » Author: flyoffacliff
I've always been interested in code and how it changes over time. Although we can debate whether or not certain aspects of electrical code are dumb and go overboard, advances such as AFCIs and tamper resistant receptacles have undoubtfully saved countless lives. But there's also many aspects of electrical safety that are quite bad and code just remains stagnant year after year. Here are my top two:

1. Edison base and other screw in lamp sockets.
The design of the screw in socket is very dangerous because it leaves the hot contact in the base of the socket completely exposed. Not only that, but the neutral is also completely exposed all around providing a path for current through an ill placed finger. This often happens when trying to replace a bulb from an awkward angle. There are many alternatives that are not only safer but easier to use, but the screw in socket not only remains legal, but is the dominant lamp socket still today.

2. The other thing is the screw terminals on the sides of switches, receptacles, and other devices.
How many times have you've seen a missing switch or receptacle plate? I've seen them not only in poorly maintained housing but also public places on occasion! This once again leaves a hot conductor completely exposed, just because a cheap little plate is missing. Why not have the screws set at an ankle to avoid accidental contact? Or have a little flap that springs closed over the screws (similar to the tamper resistant receptacle shutters)?

Apparently when wiring a hot tub, it is now required to have liquid tight conduit not just after the disconnect, but the entire way back to the INDOOR panel. This added a ton of complexity to my project for no reason. Why don't we solve the simple issues that result in the vast majority of shock incidents before going crazy with this stuff?
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joseph_125
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #1 on: September 29, 2022, 01:06:16 AM » Author: joseph_125
The one thing that always get me is that 16 gauge extension cords are allowed but aren't required to have any means of overcurrent protection beyond that of the branch circuit feeding it. In theory someone could use a 16 gauge cord to feed a heavy load and it won't trip any fuse or breaker until you reach 15A or worse 20A while 16 gauge cord is only rated up to 13A. The simple way to fix this would be to have fuses in extension cord plugs. Interestingly most power strips on the other hand are equipped with their own breaker but not extension cords.

I think fused plugs in general would be beneficial in some use cases with appliances using 10 and 16 gauge cords too IMO.

IIRC I believe the European E27 sockets fix at least part of the design, the lamp shell on those sockets aren't connected to neutral until the lamp is pretty much screwed most of the way in.

As for the exposed screw terminals, you probably could use recessed ones like on most switches and outlets used internationally or just include a snap on cover for the terminals. I think I've seen a more premium line of outlets before that had covers for the screw terminals. Still it wasn't a common thing here.
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Medved
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #2 on: September 29, 2022, 01:17:28 AM » Author: Medved
There is 3'rd, but valid only for some countries: A socket/receptacle design that does not prevent fingers to touch the contacts when live. Namely the North American design, be there are many more.


Regarding the sockets: In big parg of the world there has been an improvement, somewhere after WW2: The design must ensure no contact with live conductors should gappen before the lamp is screwed in far enough to prevent fingers touching the lamp shell. This works in conjuction of the lamp design required to have exact glass shaping and the socket a nonconductive "skirt" on its top so it efficiently blocks the finger from touching the thread. See here the compare.

And for the exposed screws: That is not legal anymore (of course for new installations), unless there is an extra cover. The requirement says, no single point failure should lead to working conductor (that means line, but a Neutral as well, pretty much everything except PE and SELV) becoming exposed. And a broken cover is considered a single point failure. So if there is a secondary cover underneath, it is OK. Of course, in most cases the cheapest way to fulfill this requirement is to design the terminals so there is nothing exposed at all, so covered crews, or most frequently (because it is the cheapest) push-in spring loaded terminals.
« Last Edit: September 29, 2022, 01:24:39 AM by Medved » Logged

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Rommie
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #3 on: September 30, 2022, 08:19:05 PM » Author: Rommie
The wiring regulations here are very different (and much stricter and more complex) than the USA, so there isn't a great deal to comment on from my perspective. I do find the obsession with partially sleeved pins on 13A plugs rather weird though; we have conducted several experiments here (with safe extra-low voltages) and we find it impossible to make contact with the pins of a plug that has no sleeving on its line and neutral pins once they have made contact with the live parts inside the socket. The only way we could do it is with the very thin probe of a multimeter, even a very small child would most likely find it very difficult if not impossible to do it (in our opinion).

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joseph_125
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #4 on: September 30, 2022, 11:15:24 PM » Author: joseph_125
Hmm interesting the BS1363 plugs weren't always sleeved. I suppose the "skirt" around the base of the plug blocks most unintentional contact with the pins, you'd really have to be intentionally trying to grab them to touch them.

As for NEMA plug designs, I suppose the common 1-15 and 5-15 plugs can be modified with the use of the sleeved pins from the Australian plugs if a sleeved pin is desired. The two pins are more or less the same size. 
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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #5 on: October 01, 2022, 06:26:48 AM » Author: Mandolin Girl
That's why you've got to watch out for the cheap crappy Chinese 'adaptors' that are all over eBay which don't have that widening of the plug next to the pins. The sleeving was introduced in 1984, but as I said we couldn't do it. Also watch out for fake IEC power cables with sleeved earth pins (that pin should definitely NOT be sleeved..!)  :poof:

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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #6 on: October 01, 2022, 08:42:54 AM » Author: Mandolin Girl
One thing to bear in mind about the regulations, no matter where you live, is that you can't legislate against stupidity.  :poof: @-@ :curse:
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Beta 5
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #7 on: October 01, 2022, 09:19:28 AM » Author: Beta 5
As Ria mentions above one of the things that has become worse is fake and substandard products. Unfortunately as people are obsessed with cheap stuff nowadays, it leads to corners being cut and dangerous electrical products existing, even though the regulations have changed over the years to make things safer.

A lot of the updates to regulations in recent years have been little things such as the requirement for consumer units to be made of non combustible materials (ie. not plastic any more) and cables and conduits to be supported by non combustible fixings in fire escape routes (so no plastic cable clips or conduit saddles in those areas), updates about EV charging and RCD's being required on all power circuits. I believe there are now also updates relating to AFDD's, SPD's and energy efficiency too.
We are currently on the 18th edition (2018) of the BS7671 wiring regulations in the UK but for the most part a installation designed to the 16th edition (1991) or 17th edition (2008) will be just as safe if no one has messed about with it.
« Last Edit: March 06, 2023, 04:33:37 PM by Beta 5 » Logged

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Rommie
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #8 on: October 01, 2022, 09:23:52 AM » Author: Rommie
We're actually now on Amendment 2 of the 18th edition, it came out earlier this year. I know, I had to shell out £95 on the thing  :poof:

It should be in the form of a ring binder that you can just change the updated sheets in, but they wouldn't make any money that way, I suppose  :-\
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Beta 5
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #9 on: October 01, 2022, 09:33:01 AM » Author: Beta 5
Indeed it does get a bit silly with the amount of times you have to buy the book! We have already had the first amendment in 2020, prior to that the 17th edition had 3 amendments in 2011, 2013 and 2015! :poof:
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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #10 on: October 01, 2022, 09:37:06 AM » Author: Mandolin Girl
More than one sparky has told me that they think that the IET are a waste of space and are only interested in making money  :-\

Incidentally, I just found a copy on eBay of the 14th edition that I used in 1971 when starting my apprenticeship in London..! That's going to make interesting reading after all this time  ;D
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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #11 on: October 01, 2022, 12:03:41 PM » Author: Mandolin Girl
One of the things that I had to do at my last job was to maintain all of the standards manuals.

All that I had to do was to exchange the old page for a new one.

If that can be done for the oil industry, than why can't it be done for the leccytrickle industry.?  :wndr:
« Last Edit: October 01, 2022, 01:27:55 PM by Mandolin Girl » Logged
Medved
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #12 on: October 02, 2022, 03:49:55 AM » Author: Medved
@replacing just the pages:

Well that is, what is done all the time anyway. But do you really have to gave tye paper version? I would guess anelectronic one is easier to maintain. Mainly when in fact you have to store many versions to the history when working on older installations, as something what is allowed now was not allowed when the thing you are actually working on was build, so unless it is just a simple wiring job, you may end up with a mish-mash of old vs new what does not comply to anything and actually becomes dangerous (some practices are really not compatible to each other, like additional grounding of the green/yellow in an 60's..70's TT installations using PE voltage triggered breakers).
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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #13 on: October 02, 2022, 07:10:48 AM » Author: Mandolin Girl
As far as I'm aware, BS7671 is only available as a printed book, if it is online I can't find it. Anyway, I prefer a print copy, I don't need a computer to look at it; I can't use those stupid  little "smart" phone screens, they're way too small..!
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Mandolin Girl
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Re: Electrical Safety Aspects That Have Not Improved Over Time « Reply #14 on: October 02, 2022, 01:29:54 PM » Author: Mandolin Girl
And there is another thing to consider with having an electronic version, how easy is it to access compared to looking up a book.?  :wndr:
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