Some of the 3 way adaptors which fit to an existing double are fused, thus limiting them to 13A total.
I believe ring mains have max permitted length and or area coverage. The current rating on a ring main should be able to be double that of the cable as in essence you have two cables in parallel. Again I believe a ring wired in 2.5mm must have a 30A breaker. Regards, Chris _____ From: [email protected] mailto:[email protected]] On Behalf Of John Allen Sent: 04 April 2005 18:02 To: Colgan, Christopher [Harman Pro Group UK]; [email protected] Subject: Re: UK Domestic Electrical Socket Outputs Chris, Jim Just taken a look at BS 1363-2: 1995, which is the part dealing with sockets - the results are interesting! Here are the most relevant bits (with an awful lot left out!) 13.12 "Multiple socket-outlets shall be capable of simultaneous use of all socket-outlets" 16 Temperature rise 16.1 "Socket-outlets and their surroundings shall not attain excessive temperatures in normal use." 16.1.1 "Compliance shall be checked by the tests described in 16.1.2, and 16.1.3 for fixed socket-outlets and portable socket-outlets respectively." 16.1.2 "…… The line, neutral and earth terminals of a single socket-outlet are connected to an incoming and outgoing 2.5 mm2 2-core and earth PVC insulated and sheathed cable as given in Table 5a of BS 6004:1991. A twin unfused socket-outlet is connected with an incoming cable as described above but with no outgoing cable. A multiple unfused socket-outlet having more than two sets of socket contacts is connected to an incoming 4 mm2 2-core and earth PVC insulated and sheathed cable as given in Table 5a of BS 6004:1991. There shall be no outgoing cable. …." "Socket-outlets under test shall be subjected to electrical loading as given in Table 5. " ... " Table 5 — Loading of socket-outlets for temperature-rise test Number of outlets Plugs with connected loads ± 0.4 A Balance of load ± 0.4 A Total load on supply cable (nominal) 1 1 × 14 A 6 20 2 1 × 14 A + 1 × 6 A 20 >1 (fused) 1 × 14 A 6 20 >2 (unfused) 2 × 14 A 28 NOTE The tolerance values for current take account of an uncertainty of measurement of not greater than ± 1.5 % at a confidence level of not less than 95 %. " 2.5sq mm cable is rated at 20A and is used for most domestic ring main and spur circuits, whereas 4sq mm is rated at 28A and is often used for commercial ring main and spur circuits (or so I believe). So, it seems - quite logically - that the rating of the socket effectively depends on the cable to which it is to be connected! Therefore it seems that sockets intended for domestic purposes must be rated at a total load of 20A (say 14A + 6A), whereas those for commercial circuits can be rated for a total load of 26A (=2x 13A). Thus you probably can both be said to be describing acceptable situations ! This brought home to me something that I nearly did wrong recently when I nearly fitted a triple 13A UNFUSED socket into an existing twin socket wall box - I never read the instructions, but I assume they said that the supply cable has to be 4sq mm! BTW: I bought that triple socket from a local branch of THE big DIY supermarket, and it was designed to convert a twin outlet into a triple outlet - I wonder how many people have fitted them to existing ring mains with 2.5sq mm cable? Regards John Allen ----- Original Message ----- From: "Colgan, Christopher [Harman Pro Group UK]" < <mailto:[email protected]> [email protected]> To: " <mailto:[email protected]> [email protected]" < <mailto:[email protected]> [email protected]> Sent: Monday, April 04, 2005 4:20 PM Subject: RE: UK Domestic Electrical Socket Outputs > Jim > > The answer lies in BS1363 of which I don't have a copy but from memory, BS1363 for some reason specifies that double outlets are only required to be rated at 13A in total. > > However, you will find that some manufacturers rate their double sockets at 13A per outlet ie 26A in total. That was the case with some MK sockets I installed at home (before the dreaded "Part P" I hasten to add). MK also do a treble outlet but they added a fuse so the total in that case was only 13A. > > <http://www.tlc-direct.co.uk/Technical/DataSheets/MK/Sockets.pdf> www.tlc-direct.co.uk/Technical/DataSheets/MK/Sockets.pdf > > Cheers > > Chris Colgan - Safety & EMC Engineer > Harman International Industries Ltd, > Cranborne House, Cranborne Road, > Potters Bar, Hertfordshire, EN6 3JN. > Tel : +44(0)1707 668081 > Fax : +44(0)1707 660755 > Soundcraft is a Harman International Company > > > > > -----Original Message----- > From: <mailto:[email protected]> [email protected] > [mailto:[email protected]]On Behalf Of Speakman, Jim > Sent: 04 April 2005 15:48 > To: <mailto:'[email protected]'> '[email protected]' > Subject: UK Domestic Electrical Socket Outputs > > > Dear Fellow Listers, > > Perhaps my brain isn't in gear today, but here goes...... > > Re UK domestic electrical sockets. Where a double electrical socket is > rated for 13 Amps, does that mean 13 Amps each side, or 13 Amps in total > ????? > > Whatever the answer might be - where is it laid down? > > Regards > > Jim > __________________________ > Jim Speakman > Thales Aerospace > Manor Royal > Crawley > West Sussex > RH10 9PZ > > > Tel: +44(0)1293 644911 > Mob: +44(0)7968 529439 > Fax : +44(0)1293 644194 > e-mail: <mailto:[email protected]> [email protected] > > __________________________ > This e-mail contains confidential information for the addressee only. If a > transmission error has misdirected this e-mail, please notify us on > +44(0)1293 644911 and delete it and all copies from your system. You should > not use, disclose, distribute or copy this communication if received in > error. > > ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. 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Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc _____ This message (including any attachments) may contain confidential information intended for a specific individual and purpose. If you are not the intended recipient, delete this message. If you are not the intended recipient, disclosing, copying, distributing, or taking any action based on this message is strictly prohibited. ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
