Extension cables and BS1363

[JohnW2]

Hi there,

I've just bought a 4-way extension lead ("PELB1751") branded "Pro-Elec", which is seemingly a trading name of Farnell. It bears a BS1363 marking.

Maybe it's just me, but I can't really make much sense of 14.10 of BS1363, which says:

I can understand that, in the case of shutters opened by simultaneous insertion of L & N pins, the 18mm minimum will prevent a compliant plug being inserted 'upside down' (with L & N reversed and E not connected).

However, traditionally (and probably still most) shutters are opened by insertion of the earth pin - which is certainly the case with the ELB1751 I have just purchased and, unless I'm missing it, BS7671 does not impose any minimum distance from earth pin receptacle to the edge of the socket. That being the case, it is possible (per photo below) to insert just the earth pin (whose 'receptacle' is only about 16mm from edge of socket), opening the shutters and hence creating a potentially 'dangerous situation'.

I was initially tempted to raise this issue with Farnell but, unless I am 'missing' something, their product does seem to be BS1363-compliant, even though seemingly 'potentially dangerous'.

Am I 'missing something'? If not, what are your views of the above (and of BS1363)?

Kind Regards, John

 

[plugwash]

it is possible (per photo below) to insert just the earth pin (whose 'receptacle' is only about 16mm from edge of socket), opening the shutters and hence creating a potentially 'dangerous situation'.

I just grabbed a tub of extension strips of various brands and ages (but afaict all of which were aquired from legitimate UK suppliers) and found

4 extention strips (branded Philex, PMS, Jo-Jo and Masterplug) that allowed this easilly.
1 extension strip (branded PMS) that barely allowed this (required some force to get the plug in upside down, but it went in).
1 extension strip (branded masterplug) that had a wide enough space above the earth pin to block this.
1 extension strip (branded masterplug) that blocked this because it was a double row design.

their product does seem to be BS1363-compliant, even though seemingly 'potentially dangerous'.

The way I see it the BS1363 shuttering rules protect against single acts of stupidity. Inserting a plug upside down, and then inserting something in the now-opened holes would be a double act of stupidity. One could equally well insert a foreign object in the earth hole and then a second foreign object in the live hole.

 

[securespark]

Although to be fair, making the multi way strips a bit wider at the top would stop the plug going in the wrong way.

I'm not thinking of acts of stupidity here, but a young kiddy.
And if that was made a bit wider, it would at least stop that.

Personally, I think that all extension sockets should be designed in the MK fashion, so you can't just access the live parts by inserting something in the earth receptacle.

 

[JohnW2]

I just grabbed a tub of extension strips of various brands and ages (but afaict all of which were aquired from legitimate UK suppliers) and found ...

A widespread 'issue', then.

The way I see it the BS1363 shuttering rules protect against single acts of stupidity. Inserting a plug upside down, and then inserting something in the now-opened holes would be a double act of stupidity. One could equally well insert a foreign object in the earth hole and then a second foreign object in the live hole.

Maybe - I certainly cannot think of any better explanation - and the rule they have for shutters operated by both live pins certainly prevents a Class I item being plugged in without an earth connection.

However, at least some people do seem to worry about the 'double act of stupidity' you refer to - and they could very easily have included an "18mm rule" for the earth pin as well as the live ones..

 

[JohnW2]

Personally, I think that all extension sockets should be designed in the MK fashion, so you can't just access the live parts by inserting something in the earth receptacle.

I'm definitely inclined to agree - but it's not just 'extension sockets', since the same issue exists with standard 'plate' sockets if mounted on a 'surface' pattress box.

 

[plugwash]

I'm definitely inclined to agree - but it's not just 'extension sockets', since the same issue exists with standard 'plate' sockets if mounted on a 'surface' pattress box.

I think the "upside down plug opens shutters" "issue" is mostly if not entirely limited to extension sockets and multi-plug adapters.

"Standard" UK plates are pretty big, and while the sockets are sometimes off-center, they are more often below-center than above center.

There do exist some surface-mount sockets using non-standard boxes, but the only ones I've seen for sale in recent decades are the MK "mini-logic" ones which use MK's "2 pin" shutter.

 

[pete01]

Just plug it in john, sit back and have a beer

 

[JohnW2]

Just plug it in john, sit back and have a beer

Do you really think that I would dream of doing otherwise?

 

[JohnW2]

I think the "upside down plug opens shutters" "issue" is mostly if not entirely limited to extension sockets and multi-plug adapters.

Very true, but ....

"Standard" UK plates are pretty big, and while the sockets are sometimes off-center, they are more often below-center than above center.
There do exist some surface-mount sockets using non-standard boxes, but the only ones I've seen for sale in recent decades are the MK "mini-logic" ones which use MK's "2 pin" shutter.

... I think what you are really saying is that 'it happens that' what have come to be 'standard UK plates' would invariably satisfy, say, an '18mm minimum' requirement for the E as well as the L & N pins.

However, even if manufacturers have (as yet!) chosen not to make them, I see nothing in BS1363 which precludes the possibility of much smaller plates ("engagement surfaces"), particularly for unswitched sockets - so, if they are going to have these rules, I don't see why they don't have a "minimum of 18mm from edge" requirement for the the earth pin (when that pin operates the shutters), just as they do for the live pins when it is they which operate the shutters?

 

[ericmark]

Seem to remember talked about here but can't find it now.

 

[JohnW2]

Seem to remember talked about here but can't find it now.

Yes, it's one of the things that the "fatallyflawed" folk have gone on about. It is there in the material you link to ....

• Some socket covers make it possible to poke pins and paper clips into the live parts!
• Broken plastic pins stuck in the earth hole - prevents shutters from closing
• Wrong size pins can make covers easy to remove, some even pop out by themselves!
• Children like to play with socket covers - plugging in upside down opens the shutter and exposes live contacts

 

[Ragnar_AT]

Since the square/rectangular back boxes have become a de-facto standard I don’t think any sane manufacturer would sell sockets that require special back boxes. That means flush sockets are extremely likely to stay as they are. Of course some manufacturer could design a more compact surface-mounted socket but how much of a market would there be?

 

[SUNRAY]

Hi there,

I've just bought a 4-way extension lead ("PELB1751") branded "Pro-Elec", which is seemingly a trading name of Farnell. It bears a BS1363 marking.

Maybe it's just me, but I can't really make much sense of 14.10 of BS1363, which says:

View attachment 403832

I can understand that, in the case of shutters opened by simultaneous insertion of L & N pins, the 18mm minimum will prevent a compliant plug being inserted 'upside down' (with L & N reversed and E not connected).

However, traditionally (and probably still most) shutters are opened by insertion of the earth pin - which is certainly the case with the ELB1751 I have just purchased and, unless I'm missing it, BS7671 does not impose any minimum distance from earth pin receptacle to the edge of the socket. That being the case, it is possible (per photo below) to insert just the earth pin (whose 'receptacle' is only about 16mm from edge of socket), opening the shutters and hence creating a potentially 'dangerous situation'.

I was initially tempted to raise this issue with Farnell but, unless I am 'missing' something, their product does seem to be BS1363-compliant, even though seemingly 'potentially dangerous'.

Am I 'missing something'? If not, what are your views of the above (and of BS1363)?

View attachment 403833

Kind Regards, John

The last time I read BS1363 was around 50 years ago while investigating the 'exception' of the used of non fused BS1363 plugs in specified environments.
I'd remembered the specified dimension being related to the earth pin to prevent a plug being inserted as you have shown, rather the the L&N pins as you have reproduced.
It makes me wonder if the reg has changed over the years (certainly the 'exception' I mentioned is no longer there AIUI and my license was revoked several decades ago) or whether I remember it wrong/misunderstood it.

 

[JohnW2]

Since the square/rectangular back boxes have become a de-facto standard I don’t think any sane manufacturer would sell sockets that require special back boxes. That means flush sockets are extremely likely to stay as they are. Of course some manufacturer could design a more compact surface-mounted socket but how much of a market would there be?

All true.

However, as far as I am aware (I may be wrong - secure may be able to tell us!) BS1363 has been 'as it is now' (in not having any minimum distance for earth pin to edge of plate) since the very first appearance of BS1363 plugs/sockets - at a time long before what is now the "de-facto standard" for face plates and back boxes had even been thought of. Indeed, in the early days, even MK surface-mounted sockets were such that I suspect a plug could be inserted upside down ....

 

[ebee]

A couple of respected You Tubers such as JW and Big Clive might see fit to produce a "How Not To" article for us?