Author Topic: What's wrong with this picture? The IEC cable that nearly killed me  (Read 2892 times)

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Offline james_s

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #25 on: July 13, 2018, 11:07:56 am »
There is certainly some crazy stuff out there, some of the pictures from other countries that have or had more lax regulations or just more DIY types and more very old structures show some really... creative work.
 

Offline Leiothrix

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #26 on: July 13, 2018, 02:35:38 pm »
The incoming active on the three prong plug, connects to the neutral of the IEC plug!!

Perhaps I'm being particularly dense today, but doesn't your picture show continuity between the two live connectors anyway?

 

Offline thermistor-guy

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #27 on: July 13, 2018, 03:06:56 pm »
...
Either fit a proper safety isolator switch or remember to *ALWAYS* physically disconnect the supply or load before touching any part of the load circuit.

This is a good habit to follow. Always do it this way.

At times it may seem unnecessary. But when you're tired, or under time pressure, or the equipment/wiring is faulty, or some moron changes your setup without telling you, and you simply act out of habit, this habit will save your life.
 

Online Hero999

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #28 on: July 13, 2018, 05:47:09 pm »
Although I do like polarised sockets and think they're much safer, than pot luck as to which conductor is phase and neutral, one should never assume the neutral conductor is at earth potential. Always treat the neutral, as if it were live!
 
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Online Whales

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #29 on: July 13, 2018, 05:49:03 pm »
The incoming active on the three prong plug, connects to the neutral of the IEC plug!!

Perhaps I'm being particularly dense today, but doesn't your picture show continuity between the two live connectors anyway?

I don't think so.  The IEC plug should have the same pin arrangement as the wall plug -- imagine it's nothing more than an extension lead.  Doing anything different would require "re-arranging" the wires in the bundle or the connectors, which makes little sense. 

Your bottom diagram might be using one of those creative definitions of 'male' and 'female' that consider the plastic rather than the pins.  Or visa versa.  I always get it wrong reading those, don't ask about SMA and RP-SMA too :D

For similar reasons I dislike datasheets that show transistor pinouts from an orthographic view, but don't label which one.  Top or bottom?  Front or back?  "Oh, you're just supposed to assume that under *standard*".
« Last Edit: July 13, 2018, 05:50:53 pm by Whales »
 

Offline Leiothrix

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #30 on: July 13, 2018, 06:05:39 pm »
The incoming active on the three prong plug, connects to the neutral of the IEC plug!!

Perhaps I'm being particularly dense today, but doesn't your picture show continuity between the two live connectors anyway?

I don't think so.  The IEC plug should have the same pin arrangement as the wall plug -- imagine it's nothing more than an extension lead.  Doing anything different would require "re-arranging" the wires in the bundle or the connectors, which makes little sense. 

It does though. If you rotate both ends so earth is up, active is on the left on both ends.
 

Offline Ian.M

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #31 on: July 13, 2018, 06:42:22 pm »
I don't think so.  The IEC plug should have the same pin arrangement as the wall plug -- imagine it's nothing more than an extension lead.  Doing anything different would require "re-arranging" the wires in the bundle or the connectors, which makes little sense. 
Nope.  The pinout of IEC 60320 C13 & C14 connectors is *supposed* to be well defined*, with the C13 trailing female connector or outlet connector, wide side down, face view, being NGL and the C14 inlet or plug, wide side down, pin view, being LGN.   The pin order in the wall socket is dependent on your national electrical wiring standards, so the cord may need to cross over the  L and N wires to maintain the correct order.   Various countries in the EU with sockets compatible with the Schuko CEE 7/7 plug are particularly problematic as their sockets are non-polarised, but the Shuko CEE 7/7 plug itself *does* have a defined polarity as it fits French  CEE 7/5 polarised sockets.   

There is additional confusion when dealing with non-technical people as they tend to call anything on the end of a cord that fits into a fixed connector a 'plug' even if it has female contacts and call a chassis mount recessed connector with male contacts a 'socket'.

* However, you'll have a hard time finding the pinout in any official IEC document that isn't behind a paywall, and its equally difficult to find a reputable manufacturer of IEC C13 & C14 connectors that actually gives a wiring diagram for their product
« Last Edit: July 13, 2018, 06:47:53 pm by Ian.M »
 

Offline Leiothrix

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #32 on: July 13, 2018, 09:38:54 pm »
Just to reply to myself, I just got a chance to measure some of my cables and active comes out on the right if earth is up.  Backwards to what I expected, but shows OP has a point I suppose.
 

Offline intabits

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #33 on: July 13, 2018, 09:47:26 pm »
I called it a "plug" because it goes inside a receptacle, even though its pins are female. 
It's not visible in the photos, but the molding has L,N & E markings, and the resistor is inserted into the one marked "N"
 

Online Monkeh

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #34 on: July 13, 2018, 10:50:36 pm »
* However, you'll have a hard time finding the pinout in any official IEC document that isn't behind a paywall, and its equally difficult to find a reputable manufacturer of IEC C13 & C14 connectors that actually gives a wiring diagram for their product

https://www.bulgin.com/media/bulgin/data/PX0587-587SE-597Wiring.pdf

Difficult?
 

Offline Ian.M

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #35 on: July 13, 2018, 11:17:52 pm »
That diagram is no help resolving the general C13 & C14 pinout problem unless you have a Bulgin PX0587, PX0588 or PX0597 connector physically in front of you or a high-res photo of one open, etc. as there is absolutely nothing to indicate whether the wiring view is with the wide side up or with it down.   I just cant understand why Bulgin and their competitors don't show the pinout on the face or pin view of their mechanical drawings.
 

Offline james_s

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #36 on: July 14, 2018, 01:19:44 am »

I don't think so.  The IEC plug should have the same pin arrangement as the wall plug -- imagine it's nothing more than an extension lead.  Doing anything different would require "re-arranging" the wires in the bundle or the connectors, which makes little sense. 

That doesn't make sense. The IEC plug is used worldwide, with the other end of the cable having whatever plugs are used locally. The only way you could have a straight-through arrangement is if there was a worldwide standard of which side live/neutral are on. The standard NEMA-15 receptacle in the US puts neutral on the left when ground is at the bottom, I don't know about foreign standards but I would not assume them to be the same other than by coincidence.
 

Online Whales

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #37 on: July 14, 2018, 11:09:10 am »

I don't think so.  The IEC plug should have the same pin arrangement as the wall plug -- imagine it's nothing more than an extension lead.  Doing anything different would require "re-arranging" the wires in the bundle or the connectors, which makes little sense. 

That doesn't make sense. The IEC plug is used worldwide, with the other end of the cable having whatever plugs are used locally. The only way you could have a straight-through arrangement is if there was a worldwide standard of which side live/neutral are on. The standard NEMA-15 receptacle in the US puts neutral on the left when ground is at the bottom, I don't know about foreign standards but I would not assume them to be the same other than by coincidence.

Oh wow.  I didn't think of the wall sockets also being re-arranged. 

... do international plug adapters re-arrange the A & N?  Given some of them are "multi-standard" I presume this can't be done reliably.

Then there's also the issue of dog-leg 240V, where both the A & N are hot.

Any hope of either wire in a C13/C14 being reliably neutral, even if it was when I tested yesterday,  is now gone in my mind  ;D 
« Last Edit: July 14, 2018, 11:16:29 am by Whales »
 

Online Monkeh

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #38 on: July 14, 2018, 11:16:31 am »
That diagram is no help resolving the general C13 & C14 pinout problem unless you have a Bulgin PX0587, PX0588 or PX0597 connector physically in front of you or a high-res photo of one open, etc. as there is absolutely nothing to indicate whether the wiring view is with the wide side up or with it down.   I just cant understand why Bulgin and their competitors don't show the pinout on the face or pin view of their mechanical drawings.

It's.. pretty obvious it's a top down view.
 

Offline Mr. Scram

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #39 on: July 14, 2018, 12:00:06 pm »
That's not even plug related tbh. There were (and still is not in many countries, I'd guess majority) no laws saying which side of socket should get L and which N (just recommendations and best practices) so you can't ever assume it is wired correctly (well, most of the time it will be, but there are always some shitty installations, or just bad electricians).
There generally is no "correctly" when it comes to schuko. That's what many people unfamiliar with the standard seem to struggle with. There is no presumption of what is a right and wrong side as it's all fully reversible, so accidents with installations where phase and neutral are swapped can't occur. As long as ground is in the right place you're basically good, avoiding the dangerous assumptions and badly followed standards of polarised sockets.

That being said, there are various sockets and plugs being used and not all play nice.
 

Online Hydron

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #40 on: July 14, 2018, 10:19:56 pm »
One should consider both wires as potentially hot. There is a chance that the neutral return wire might be disconnected somewhere and thus power through another consumer.

I don't know the NZ plugs, but there might be another problem: the ground pins also looks to be sleeved. At least with the UK plugs this is a problem, as the ground contact might be to far up the pin.
This ^^

I have not read the entire thread, but can confirm that NZ/AU plugs are NOT meant to have sleeving on the earth pin, so you have a poorly made and non-compliant cable in more ways than one. The sleeving-on-PE thing can be very dangerous, but given it'd be more effort than just leaving it bare it boggles my mind as to why the shady manufacturers keep doing this.
 

Online nuno

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #41 on: July 14, 2018, 10:52:11 pm »
As some have already mentioned I also disconnect the cable from mains when working on mains devices.
I have the rule that I must keep the disconnected plug in my viewsight before I start working on the device; and never just unplug it and leave it near the socket, I leave it "far apart" from it.
« Last Edit: July 15, 2018, 07:54:54 am by nuno »
 

Offline james_s

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #42 on: July 15, 2018, 01:45:09 am »
I have not read the entire thread, but can confirm that NZ/AU plugs are NOT meant to have sleeving on the earth pin, so you have a poorly made and non-compliant cable in more ways than one. The sleeving-on-PE thing can be very dangerous, but given it'd be more effort than just leaving it bare it boggles my mind as to why the shady manufacturers keep doing this.

Likely ignorance, it's not hard to believe that a lot of people out there don't understand the purpose of the sleeving and figure if it's good to have it on two of the prongs then it's better to have it on all three. The sleeved prongs are quite a nice feature which I had never seen until I encountered British plugs. A nice design overall aside from being so bulky, but anything is a compromise.
 

Online Hydron

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #43 on: July 15, 2018, 07:41:15 am »
The sleeving works best on british plugs - the pins are so massive that a nice thick insulator can be added without reducing strength by any noticeable amount.
On NZ/AU plugs either the sleeving is pretty thin (and thus fragile, I've had it crack off when using those multi-country adaptors with shutters that end up applying pressure to the sides of the pins) or the pin gets narrowed and loses some strength.
The sleeving requirement can of course be eliminated by designing the socket with a recess for the plug (e.g. Shuko and other continental European types).

As for working on mains equipment, I either have the plug out and where I can see it, or when that is impossible I stick a meter in there to measure neutral&live->PE voltages before and after the switches are turned off (so that I can be sure it's both wired correctly and is fully off).
 

Offline Mr. Scram

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #44 on: July 15, 2018, 08:52:12 am »
The sleeving works best on british plugs - the pins are so massive that a nice thick insulator can be added without reducing strength by any noticeable amount.
On NZ/AU plugs either the sleeving is pretty thin (and thus fragile, I've had it crack off when using those multi-country adaptors with shutters that end up applying pressure to the sides of the pins) or the pin gets narrowed and loses some strength.
The sleeving requirement can of course be eliminated by designing the socket with a recess for the plug (e.g. Shuko and other continental European types).

As for working on mains equipment, I either have the plug out and where I can see it, or when that is impossible I stick a meter in there to measure neutral&live->PE voltages before and after the switches are turned off (so that I can be sure it's both wired correctly and is fully off).
There are also plugs that have the "sleeve" be part of the plastic body and quite hard and sturdy, rather than a thin layer added later.
 

Offline gbaddeley

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #45 on: July 15, 2018, 09:33:47 am »
Good to pull the plug.
Yes, so easy to do, and no chance of dodgy mains wiring giving you a bad day.

Quote
Here in the US I use one of those little $5 LED testers to confirm outlets are wired correctly. More importantly, I use it to confirm my many power strips are wired correctly and not floating.
I have 2 neon panel lights wired on L-E and N-E on the output socket of my variac. Provides a quick visual check that all is OK.
Glenn
 

Offline KL27x

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #46 on: July 15, 2018, 01:07:52 pm »
When it comes to power sockets and cables, everyone except practicing electricians is dyslexic. Having a standard in place is easy. Trusting it is a pipe dream.

I will always use DPST switch when possible to interrupt both lines. Not to parallel up on one and leave the the other constantly connected. Even the cheapest of chinese import goods/tools I've bought which run directly off mains without a transformer have this setup on the power switch. I think maybe it's part of being "double insulated?"

I have some reversed power cables from Chinese T12 irons. When I discovered it, my first thought was to throw them out. Then my second thought was... it doesn't change anything as far as I'm concerned. I suppose the fuse should go on the live side, if possible. That's about it. I mean, I discovered the problem, because it must have "mattered" to what I was doing, at the time (honestly can't remember). But not in any way that would have shocked me. I don't trust myself to know which is live or neutral, let alone whoever wired my house or supplied my IEC cable. :)

The ubiquity of the reversible figure 8 non-grounded cord/connector is proof this live/neutral thing was never more than a "looks good on paper" kind of bureaucratic achievement.


 
« Last Edit: July 15, 2018, 02:22:01 pm by KL27x »
 

Offline basinstreetdesign

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #47 on: July 15, 2018, 05:05:55 pm »
Yesterday I received a strong electric shock, of the most dangerous kind - through both arms and the chest area.  (posted here as it's a "catch-all" category)

I was using my variac contraption to test a new dummy load project, and had both switches on it turned off as I was adjusting the position of the variac and the load. I was holding the variac handle with one hand, but a finger on the other hand touched a wire on the dummy load when I got the boot.
Most fortunately, the RCD that I had fitted to the variac contraption tripped and saved me.

The neutral coming out off the variac was live...

This kind of crap is all too common.

This is exactly the reason why hospital-grade power cords in Canada must have transparent plastic molded ends so that anyone can see what wire goes to what pin of the connector.  And all of the wires must be different colours: black, white, green/yellow.
STAND BACK! I'm going to try SCIENCE!
 

Offline thermistor-guy

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #48 on: July 16, 2018, 10:45:57 am »
...
This is exactly the reason why hospital-grade power cords in Canada must have transparent plastic molded ends so that anyone can see what wire goes to what pin of the connector.  And all of the wires must be different colours: black, white, green/yellow.

I use transparent ends when I reterminate older power cords, or when I make short US-to-AU conversion leads, for the same reason: to allow visual inspection.
 

Offline intabits

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Re: What's wrong with this picture? The IEC cable that nearly killed me
« Reply #49 on: July 16, 2018, 01:49:24 pm »
I cut open that cable, and it had the internal blue/brown colours wired correctly to the IEC end, but wrong for the AU plug end.
They were also pretty piddly conductors, I doubt anything like the 10A stated on the plug - binned the lot.

I'm thinking of adding a feature to the variac to catch swapped active & neutral wires.
A lowish voltage MOV, say around 60-120V, in series with a 5W resistor such that 240V would cause 100-200mA to flow, and connected between Neutral and Earth, after the RCD.
Then if neutral were live, the RCD would trip. Worth doing? Are there any possible issues that I'm not seeing?
 


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