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Topic Title: BS 1363 Plug top
Topic Summary: Max cable size
Created On: 09 May 2013 02:40 PM
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 09 May 2013 07:17 PM
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sparkingchip

Posts: 5820
Joined: 18 January 2003



Nice use of a plugtop

The plugtop at the front has 1.5mm three core SWA coming out of it, the "electrician" said it was expensive cable, but had to be used for safety reasons!
 10 May 2013 10:33 AM
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iie63674

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Originally posted by: OMS

Provision shall be made for the entry and effective clamping without bending of 2-core and 3-core flexible cords for rewirable plugs as given in Table 11, Table 12, Table 13, Table 26 and Table 27 of BS 6500:2000, having nominal conductor cross-sectional areas not exceeding 1.5 mm2.



extracted from BS 1363-1:1995 and A4:2012



regards



OMS


I think that extract is being misunderstood. It does not say that the plug shall not accept a conductor greater than 1,5mm2, only that a plug shall be capable of accepting conductors up to and including 1,5mm2. It says nothing about the acceptability of 2,5mm2.
2,5mm2 flex is useful for rough-service extension leads - nothing to do with current-carrying capacity, just mechanical robustness. I have a few at home, with with 2,5 TRS and MK plugs.
 10 May 2013 10:46 AM
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OMS

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I disagree

The Standard is quite clear that the plug must accept conductors not exceeding 1.5mm2.

It says nothing about larger conductors being accepted - if due to a particular make or manufacture, it's physically possible to deploy a larger conductor CSA (and the cord clamping remains effective) then clearly the product is being used outside of the requirements of the standards and thus the risk is with the person choosing to do that.

Regards

OMS

-------------------------
Failure is always an option
 10 May 2013 11:17 AM
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Legh

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I had a similar dispute after PATing in a pub. The coffee machine and grinder supplied on a lease had nice thick 3-core rubber cables attached to 13A BS 1363 plugs. As you might guess the cable clamp wasn't used. The company was called by the tenant landlord and after their technicians had made a visit nothing else was done.

So I expect they considered that BS really did stand for BS.

The most i could do was notify the landlord and submit my invoice.

Legh

-------------------------
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 10 May 2013 11:55 AM
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iie63674

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OMS, the standard, like most standards, sets minimum requirements. If a manufacturer chooses to exceed some of those minimum requirements he is free to do so, provided that all the normative provisions are met.
Are you saying that you think all the plugs that use a 'binding post' arrangement, where the conductor is wrapped around a threaded stud, are non-compliant?
 10 May 2013 12:35 PM
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OMS

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Originally posted by: iie63674

OMS, the standard, like most standards, sets minimum requirements. If a manufacturer chooses to exceed some of those minimum requirements he is free to do so, provided that all the normative provisions are met.

Are you saying that you think all the plugs that use a 'binding post' arrangement, where the conductor is wrapped around a threaded stud, are non-compliant?


I agree the standards set the minima, but what then when the plug top needs replacing with one by a manufacturer who has only met the minimum provision - the 2.5mm2 is now a problem - it's a minor problem on one plug top - it's more of in issue when you have a building full of them.

I've no problem with a product exceeding a standard - just that we shouldn't be saying that's OK, jus cos it happens to fit.

A plug top is designed to accept a 2 or 3 core cable withinin a defined group and not exceeding 1.5mm2 - to use anything else in terms of cable and CSA is clearly using the plug top outside that standard.

Take the case of a fatality when someone used an extension lead manufactured with a 2.5mm2 cable and a BS 1363 plug top - how/where would it go when the expert witness stood up and said the lead didn't comly with a standard and then sat down again - no further explanation required.

Regards

OMS

-------------------------
Failure is always an option
 10 May 2013 01:10 PM
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iie63674

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But OMS, in your fatality example the plug does comply with the standard! I agree it could be an interesting argument in a court, but in order to prove compliance the plug manufacturer would simply have to show that the plug could accept a cable with conductors that didn't exceed 1,5 mm2. The standard doesn't prohibit the acceptability of larger conductors, it is just silent on that subject.

I take your point about the possible need for replacement, and I can see how that could be a problem. I think most plugs on the market would accept a 2,5 mm2 conductor in the terminals, but the ability of the cable grip to accept a 3-core 2,5 mm2 is another matter.
 10 May 2013 01:14 PM
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ectophile

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Originally posted by: OMS
Take the case of a fatality when someone used an extension lead manufactured with a 2.5mm2 cable and a BS 1363 plug top - how/where would it go when the expert witness stood up and said the lead didn't comly with a standard and then sat down again - no further explanation required.



Regards



OMS



Assuming that the manufacturer has taken the trouble to source a plug that is capable of accepting a 2.5mm2 cable, and they have confirmed this with the plug's manufacturer, then what part of the complete assembly would not comply with standards?

-------------------------
S P Barker BSc PhD MIET
 10 May 2013 01:17 PM
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iie63674

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Originally posted by: ectophile

Originally posted by: OMS

Take the case of a fatality when someone used an extension lead manufactured with a 2.5mm2 cable and a BS 1363 plug top - how/where would it go when the expert witness stood up and said the lead didn't comly with a standard and then sat down again - no further explanation required.







Regards







OMS






Assuming that the manufacturer has taken the trouble to source a plug that is capable of accepting a 2.5mm2 cable, and they have confirmed this with the plug's manufacturer, then what part of the complete assembly would not comply with standards?

And why would it be an issue, unless the use of a 2,5mm2 conductor had in some way contributed to the incident?
Actually the larger conductor (given the caveat about confirmation by the manufacturer) should be more safe; more material for the cable clamp to grip on, better heat dissipation, greater mechanical strength...
 10 May 2013 01:24 PM
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OMS

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and it's that silence that will generally prove to be the problem.

Look at it the other way - if the extension lead is the culprit, and the plugtop complies with BS 1363, can you see the plug top manufacturer rushing to be a co defendant with the lead manufacturer or the individual who made it up on site.

On the other side of the electrical fence, the socket outlet also has defined conductor sizes - but to pick on one manufacturer like MK thier product has terminal capacity to accept more conductors than the standard requires. I would take a view that say 4 x 2.5mm2 conductors into a terminal is a noncompliance as the socket design by the manufacturing standard permits a maximum of 3 x 2.5mm2.

I would always make my initial view that installation standards require equipment to be in accordance with thier relevant product standards - if they are deployed outside of that standard then the installation standard cannot be complied with. You could take this view upwards in say PUWER - if the company supplied that 2.5mm2 extension lead and there is an acident then where would that go ?

I'm not saying don't do it - that's the choice for the relevant person - just that the standard is based on specific criteria - varying from that may be a problem, particularly if we take the silence on an issue into account - the assumption being it's disallowed unless allowed.

regards

OMS

-------------------------
Failure is always an option
 10 May 2013 01:44 PM
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sparkingchip

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Why would you want to get a 2.5mm flex into a 13 amp plug top in the first place? If the appliance needs a flex that size the plug top doesn't have the capacity for it anyway.

Are you going to tell me it's because of the volts drop on a huge extension lead? What other possible explanation can there be?

Andy
 10 May 2013 01:58 PM
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rocknroll

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Okay I waited a bit, but now time to upset the forum regulation police with items in possession;

2 x LV lighting transformers 10 x 12V, heavy duty sealed for outdoor use black silicone rubber cable containing 2 x 2.5 tinned copper conductors into a moulded plug, with BS conformities.

1 x stand alone double insulated circular halogen patio heater white flex with 2 x 2.5 conductors into a white moulded plug. BS kitemark.

1 x large electric chainsaw double insulated with 2 x 2.5 conductors into a moulded plug.

And now the 'piece de resistance'

1x 3kva 110V transformer 3 core 2.5 cable into a moulded plug.
1x Worx heavy duty chipper 3 core 2.5 cable into a moulded plug.

So something went wrong there eh!!!!!

regards

-------------------------
"Take nothing but a picture,
leave nothing but footprints!"
-------------------------
"Oh! The drama of it all."
-------------------------
"You can throw all the philosophy you like at the problem, but at the end of the day it's just basic electrical theory!"
-------------------------
 10 May 2013 02:39 PM
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iie63674

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Andy, voltage drop might be one reason, but the main reason is mechanical strength.
 10 May 2013 02:41 PM
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OMS

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For sure it went wrong Rock - the company putting the CE mark on the products for a start.

I looked into this a while back - the appliance is a "standard" design for the euromarket - it's just us awkward sods across the channel to them use the BS 1363 plug (unless you count the german penchant for using them as inlet devics for portable PV systems) - everyone else tends towards an unfused pattern plug with usually 16A circuit protection - so 2.5mm2 flex is not unreasonable - and the Euro's don't understand our wiring practices at all.

regards

OMS

-------------------------
Failure is always an option
 10 May 2013 02:52 PM
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iie63674

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Originally posted by: OMS

For sure it went wrong Rock - the company putting the CE mark on the products for a start.

regards



OMS


And which EHSR, of which Directive, do you think is not complied with by a 2,5 mm2 cable?
 10 May 2013 03:11 PM
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ebee

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Hoy!

Stop saying "2,5 mm2 cable" that is incorrect.
Say "2.5 mm2 cable" that is correct.
There is such a thing as a decimal point.
There is not such a thing as a decimal comma!



-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 10 May 2013 03:19 PM
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iie63674

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Oh No! Now I've upset another of the forum regulars!

However, since we're discussing standards, here's an extract from the ISO/IEC Directives (Rules for the structure and drafting of International
Standards):

6.6.8 Representation of numbers and numerical values
6.6.8.1 The decimal sign shall be a comma on the line in all language versions.

I can't tell you when that was agreed, my records on this subject only go back to 1992. Do try to keep up!
 10 May 2013 03:29 PM
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ebee

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You have not really upset me.
I was only Joking.
Mathematically it is a point but by convention in order to differentiate between mm and inches is often used for very sound reasons (done so meeself loadsa times in an engineering background).



-------------------------
Regards,
Ebee (M I S P N)

Knotted cables cause Lumpy Lektrik
 10 May 2013 04:23 PM
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OMS

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Originally posted by: iie63674

Originally posted by: OMS

For sure it went wrong Rock - the company putting the CE mark on the products for a start.

regards

OMS


And which EHSR, of which Directive, do you think is not complied with by a 2,5 mm2 cable?


I'll open the bidding with 1.5.4 of The Supply of Machinery (Safety) Regulations 2008 and go from there to the LV directive -

Oh No! Now I've upset another of the forum regulars!


Nahh - it's just a debate - I don't offend that easy

Regards

OMS

-------------------------
Failure is always an option
 10 May 2013 05:07 PM
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westfield6

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Originally posted by: ebee

Hoy!



Stop saying "2,5 mm2 cable" that is incorrect.

Say "2.5 mm2 cable" that is correct.

There is such a thing as a decimal point.

There is not such a thing as a decimal comma!





And while we are about it stop calling plugs plug tops. A plug top is the lid or cover held on the plug with one or two screws.
IET » Wiring and the regulations » BS 1363 Plug top

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