UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Other Vintage Household Electrical or Electromechanical Items

Notices

Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details.

Reply
 
Thread Tools
Old 2nd Jul 2019, 2:22 pm   #41
GrimJosef
Nonode
 
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 2,532
Default Re: 13 amp fuse for 1.5mm mains flex?

As an example of the confusion, I recently had a very large valve amp in for service. It was fitted with an IEC C14 inlet and the instruction manual explicitly said that the amp was only to be used with the manufacturer's supplied IEC C13 mains lead. Unfortunately that lead hadn't made it as far as me. The amp's onboard mains fuse was rated F6.3A, which wouldn't provide overload protection for, say, a 5A-rated lead.

So in the spirit of playing by the rules I thought I'd order a suitably high-rated lead. I chose one from CPC, a reputable supplier - their order code PL14263. This is described, unambiguously you might have thought, as a 2.5m UK Plug to IEC C13 Socket Mains Lead, 10A Black - UKIEC10A2.5M and the description on its web page says its current rating is 10A.

The picture shows the item which turned up. Let's start with the IEC connector. This (blue ring) is stamped 10A. Good start. The cable (green ring) says 3 x 1.0mm2. According to Lucien's list further up that should also be fine for 10A. So far so good. But when I opened the fuseholder I found (yellow ring) a 5A fuse. Hmmm. And the stamp on the BS1363 plug (red ring) says 5/250, which I'd always understood to mean 5A, 250V.

So is my lead a 10A lead or is it really a 5A lead ? Maybe I should take this up with CPC. As it was I used it - the amp didn't draw nearly 5A of course - but I didn't leave it unattended.

Cheers,

GJ
Attached Thumbnails
Click image for larger version

Name:	10A mains lead or is it 5A.jpg
Views:	84
Size:	105.4 KB
ID:	186078  
__________________
http://www.ampregen.com

Last edited by GrimJosef; 2nd Jul 2019 at 2:44 pm.
GrimJosef is offline   Reply With Quote
Old 2nd Jul 2019, 4:18 pm   #42
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,154
Default Re: 13 amp fuse for 1.5mm mains flex?

That's when I would certainly make my own mains lead using a rewireable !EC socket and at least 1.25mm^2 mains cable.
TonyDuell is offline   Reply With Quote
Old 2nd Jul 2019, 4:37 pm   #43
gramophone1
Pentode
 
Join Date: Apr 2018
Location: Tyne and Wear, UK.
Posts: 113
Default Re: 13 amp fuse for 1.5mm mains flex?

The mains lead is rated at 5 amp. The iec is rated at 10 amp. You can only use a 5 amp fuse maximum according to the rating on the plug.
gramophone1 is offline   Reply With Quote
Old 2nd Jul 2019, 5:41 pm   #44
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 4,977
Default Re: 13 amp fuse for 1.5mm mains flex?

But if the lead as a whole is specified as a "10A lead," then all four components (mains plug, IEC connector, cable, and fuse) should be rated for 10A. Surely a case of misrepresentation in the CPC catalogue, albeit not intended fraudulently?
kalee20 is offline   Reply With Quote
Old 2nd Jul 2019, 6:11 pm   #45
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,294
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
Originally Posted by Refugee View Post
I have seen 4 way extension leads on sale marked 10 amps and fitted with a 10 amp fuse..
If the connecting-cable is not rated for anything higher, then that's the correct thing to do. I've got a bucketful of similarly-rated 4-outlet extension-leads - typically used to feed a TV, a Sky-box or PVR, a broadband-router and a games-console, all plugged into a 13A wall-outlet. The total current-draw is less than an amp, and I'm quote happy to give someone such an extension-lead.

Let's not over-analyse this! The world is - as statistics prove - definiotely _not_ burning-down-to-the-ground because of hypothetically-under-rated flexes or marginally-over-specified fuses.

Let's just get on and let people enjoy their 21st-century multimedia setups in peace!!
G6Tanuki is offline   Reply With Quote
Old 2nd Jul 2019, 6:26 pm   #46
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 3,154
Default Re: 13 amp fuse for 1.5mm mains flex?

My worry about those 10A distribution board leads is that 10A fuses are not common. Yes RS sell them, but you probably won't find them in a high street shop. So if said fuses blows for whatever reason then j-random-public is likely to put a 13A fuse in its place. I prefer it if things are safe and operational with either a 3A or 13A fuse (as appropriate) and no other value.

Mind you some of those so-called 10A leads don't look as though they would carry 1A.

The only '10A' distribution board I have here is a rather expensive (when new) thing with a dozen IEC C14 sockets on it. It's useful on the bench for running test gear, etc, off (most instruments take <1A of course). It has a fuseholder containing a 10A ceramic cartridge fuse (20mm long). When I got it second-hand, the mains lead had been cut off, so I replaced it with 1.5mm^2 cable (I have a reel of that) and fitted a plug with a 13A fuse. To me that is safe. The plug fuse protects the cable (which will stand 13A), the internal fuse protects the sockets/load.
TonyDuell is offline   Reply With Quote
Old 2nd Jul 2019, 6:38 pm   #47
GrimJosef
Nonode
 
Join Date: Sep 2007
Location: Oxfordshire, UK.
Posts: 2,532
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
Originally Posted by G6Tanuki View Post
... Let's not over-analyse this! The world is - as statistics prove - definiotely _not_ burning-down-to-the-ground because of hypothetically-under-rated flexes or marginally-over-specified fuses ...
True. But things are failing. My sister called me a couple of months ago to ask my advice after the '13A' plug on the end of the cheap extension lead which was powering the tumble drier in her garage was found to have melted. It had a 13A fuse in it. There was nothing wrong with the tumble drier. But the extension lead plug was a poor thing, toleranced right to the bone (actually beyond, clearly) and it had failed, albeit failed safe. My advice was to buy a better quality extension lead, if she could find one, or to cut the remains of the cheap plug off the lead she had and to fit a better one with a recognised brand name.

Cheers,

GJ
__________________
http://www.ampregen.com
GrimJosef is offline   Reply With Quote
Old 2nd Jul 2019, 9:19 pm   #48
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,737
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
I have seen 4 way extension leads on sale marked 10 amps and fitted with a 10 amp fuse..
These are a menace, in my view. The cable is 1.0mm˛ and thus only rated for 10A. As they are typically short, for a few more pennies the cable could be 1.25mm˛, the fuse 13A and the job done properly. As Tony says, many people will not have a 10A fuse to hand if needed, so it will be replaced with a 13A.

My concern is more that if the cable is used to extend one full-load appliance that takes close to 13A, typically a 10A fuse will not blow. The fuse (and hence the plug) and the cable will run hot, dissipating up to 69% more heat than intended, for weeks or months before thermal fatigue gets the better of the fuse. Heat conducted down the line pin from a marginally overrun fuse can weaken the spring temper in the wall socket contact, if the plug does not melt first, making the socket unfit for use even with a new extension lead. Many of these accessories have flimsy contacts that are barely good for 13A in the first place, and certainly can't take any extra heat.

Overheating from continuous low overload insufficient to blow a fuse or trip an MCB, is a frequent cause of electrical burnouts because it is progressive. Hot fuse leads to oxidised contacts / weakened contact springs, leads to high resistance, leads to another source of heat...

Quote:
So is my lead a 10A lead or is it really a 5A lead ? Maybe I should take this up with CPC. As it was I used it - the amp didn't draw nearly 5A of course - but I didn't leave it unattended.
It's a mismatched set of parts, so should not be sold as-is. Most likely someone put the 10A cables in the wrong overmoulding line and they came out with '5A' plugs attached. However, AFAIK there is no difference between a 13A plug stamped 5A, and one stamped 13A. Those marks are really instructions to the user as to what rating of fuse should be fitted for the cable, as it is the cable CSA and socket contact type that actually limit the working current. I dissected differently marked plugs of the same brand and the fuse clips, spot weld tabs etc were all identical. So at a pinch, I would put a 10A fuse in that cordset and call it a 10A cordset. But better, send it back. CPC offer reasonable pricing on these things but they need to be kept on their toes about QC.
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 2nd Jul 2019, 10:08 pm   #49
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,294
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
My concern is more that if the cable is used to extend one full-load appliance that takes close to 13A, typically a 10A fuse will not blow. The fuse (and hence the plug) and the cable will run hot, dissipating up to 69% more heat than intended, for weeks or months before thermal fatigue gets the better of the fuse.
Yet, to be honest, just how many things in your house can you name that take the full 13A?

The highest-demand appliance I have here [apart from the MIG-welder!] is a Samsung washing-machine: it's a modern "cold-fill" one which takes only 1.9Kw when the heater is energized.

I also have a bunch of electric fan-heaters here: the most-powerful of which is rated at 1.7Kw

All of that is well within 10A.

I'm happy to power my washing-machine and fridge down a 2-outlet 10A-rated extension-lead (there's only one 13A outlet behind the kitchen-units) and so far no life-changing events have occurred.

I've opined previously that the 13A outlet is vastly and uneconomically overspecified/over-engineered for the majority of 21st-century UK electrical loads. Nothing I've seen to date has deterred me from this opinion.
G6Tanuki is offline   Reply With Quote
Old 2nd Jul 2019, 10:23 pm   #50
emeritus
Dekatron
 
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 3,144
Default Re: 13 amp fuse for 1.5mm mains flex?

Yes, it''s some time since 3kW kettles and electric fires were on sale. I assumed that the switch to lower powered devices was so that the same product could be sold in mainland Europe, where the 10A sockets often found limit you to about 2.2kW.
emeritus is offline   Reply With Quote
Old 2nd Jul 2019, 10:40 pm   #51
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,737
Default Re: 13 amp fuse for 1.5mm mains flex?

I have some 3kW fanheaters, not that old, and recently a tumble dryer with a rated load of 11.75A. Increasingly, built-in cookling appliances are being supplied with 13A plugs or ratings suitable to be fed from them, which may use near 13A for a while before they start cycling on the thermostat. For convenience, installers are fitting 13A sockets behind the units, fed from the isolator above the worktop. Examples have been found by electricians of overheated trailing sockets used to connect ovens etc to the nearest point when not behind the correct unit.

I agree that an increasing proportion of domestic loads are trivially small. But is it worth disrupting the universal compatibility of all plugs in all sockets to equip smaller loads with physically smaller plugs? Is that a return to tbe bad old days?`
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 3rd Jul 2019, 1:04 am   #52
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 4,117
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
Originally Posted by Lucien Nunes View Post
Quote:
I have seen 4 way extension leads on sale marked 10 amps and fitted with a 10 amp fuse..
These are a menace, in my view. The cable is 1.0mm˛ and thus only rated for 10A. As they are typically short, for a few more pennies the cable could be 1.25mm˛, the fuse 13A and the job done properly. As Tony says, many people will not have a 10A fuse to hand if needed, so it will be replaced with a 13A.
The 10 amp ones I have are mainly for charging stations where phones and cameras and various other gadgets are charged.

Like magic I have rustled up one in retail packaging for a quick tear down.
The fuse clips are nice and tight however the plug body looks a little thin.
The plug body material has the feel of textured nylon.
The socket strip itself is a bodger's special with shutters that can be opened with the earth pin of any 13A plug.
Attached Thumbnails
Click image for larger version

Name:	DSCF5530.jpg
Views:	55
Size:	59.7 KB
ID:	186112   Click image for larger version

Name:	DSCF5537.jpg
Views:	60
Size:	55.7 KB
ID:	186113  
Refugee is offline   Reply With Quote
Old 3rd Jul 2019, 1:16 am   #53
Boulevardier
Hexode
 
Join Date: Sep 2017
Location: Bristol, UK.
Posts: 254
Default Re: 13 amp fuse for 1.5mm mains flex?

"But is it worth disrupting the universal compatibility of all plugs in all sockets to equip smaller loads with physically smaller plugs? Is that a return to the bad old days?"

Totally agree that a return to those bad old days is a very bad idea. Some of us can remember those horrific "christmas trees" of variegated sizes of brown, round-pin plugs and multi-way/multi-size adaptors that were once seen in houses wired up in the 1930s/1940s. 13 Amp sockets and ring mains - plug any appliance (bar immersion heaters, cookers, etc) into any socket (even if the advent of the twin 13A socket did b***** that up a bit). That universal compatibility is worth fighting to the death for!

Mike
Boulevardier is offline   Reply With Quote
Old 3rd Jul 2019, 10:42 am   #54
Bookman
Pentode
 
Join Date: Aug 2017
Location: Taunton, Somerset, UK.
Posts: 244
Default Re: 13 amp fuse for 1.5mm mains flex?

There is perhaps a slight misunderstanding of usage associated with equipment ratings. In this I would refer first to cable sizing which must be rated to carry safely the nominal expected and/or calculated load current of the circuit over the length of cable employed.

Fuses however are over current devices that are used to isolate power to the circuit under varying fault conditions hence the types of fuses that are available. MCBs incidentally have a range of IDMT (Inverse Definite Minimum Time) tripping characteristics curves that attempt to mirror more accurate fuse curves.
Here it is important to bear in mind that most if not all electrical installations will have fuses or breakers that will need to have some form of coordination. For example you would not want your trailing socket to blow an upstream fuse and put all the lights out.
It is to be noted that certain MCBs will in fact have internal fuses fitted owing to their inability to provide short circuit protection for given applications.
Bookman is offline   Reply With Quote
Old 3rd Jul 2019, 11:00 am   #55
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,737
Default Re: 13 amp fuse for 1.5mm mains flex?

True, however this thread is primarily about the protection of portable appliances, cordsets and extension leads and their components, rather than the wiring of fixed installations. It is assumed that 13A socket outlets installed in accordance with BS7671 will provide co-ordination with the plug fuse, although practical experience shows that over certain ranges of fault current this is not always the case, especially where 20A radial circuits are used.

Quote:
Like magic I have rustled up one in retail packaging for a quick tear down.
Thanks for that... can you confirm that it has 1.0mm˛ cable?

Re. small plugs for small appliances, there is theoretically the option to have a slimline 2-pin plug that will fit a standard socket, like the CEE7/16 Europlug. The Europlug is rated at 2.5A for class II appliances only, is not available in a rewireable form and although it has to be as wide as a full size earthed plug to match the pin centres, is slim in one dimension. It will open the shutters in any shuttered version of European socket, as they use the 'simultaneous engagement' mechanism, like older MK sockets in the UK.

We're snookered on that one, though, as a many of our sockets use the earth pin or ISOD to open the shutter. Phone chargers and similar are now sometimes equipped with a retractable ISOD to reduce the profile of the charger when carried in a bag or pocket. We also need a fuse, although it would be possible to integrate a 5x20mm or BS646 fuse endways between the pins. CEE7/16 did not exist as an example when BS1363 was under development, and we were long used to the peculiarity of the pin spacing of 2-pin plugs to BS372 part 1 being different to their 3-pin equivalents. Perhaps that guided the thinking away from the option of the downward-compatible lightweight plug option?

The 'Fireside' socket was one response. one 13A and two 2A 3-pin sockets with integral fuse. Not downward-compatible, but a recognition that the 13A plug was an overkill for many applications. There was also a 4-gang 2A version in the same profile and a fused outlet terminal on the normal one to feed it. With the pair, you got 1x 13A and 6x 2A in two faceplates. Problem was you still had to unplug the fire to use the vacuum cleaner!
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 3rd Jul 2019, 12:04 pm   #56
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 4,977
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
Originally Posted by G6Tanuki View Post
I've opined previously that the 13A outlet is vastly and uneconomically overspecified/over-engineered for the majority of 21st-century UK electrical loads. Nothing I've seen to date has deterred me from this opinion.
It may be over-specified, but I'd say it is under-engineered not over!

Given that it IS specified as 13A, if you run it at 13A it is only just capable. A bit of tarnish on the contacts, a bit of spring weakening, and it gets hot, making both these problems worse. It just doesn't quite do what it says on the tin.

With less powerful appliances, as you say, things are OK. So if we redefine the amp so that 13 new amps = 10 present amps, then it's fine! (Just need to thin-down the fuse wire in the 'new' 13A fuses).
kalee20 is offline   Reply With Quote
Old 3rd Jul 2019, 12:59 pm   #57
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,737
Default Re: 13 amp fuse for 1.5mm mains flex?

The weak points are specifically the fuse clips, and the socket contacts in lower-quality accessories, which have imprecise contact area and pressure being little more than bent bits of strip of dubious composition. Reference to high quality products, such as older MK examples, shows what can and should be done.

I have often wondered whether a superior 'high endurance' plug with some additional clamping arrangement for the fuse, such as a steel spring around the contact clips or even a screw clamping arrangement, might find favour with industrial users.
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 3rd Jul 2019, 1:12 pm   #58
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 7,294
Default Re: 13 amp fuse for 1.5mm mains flex?

Quote:
Originally Posted by Lucien Nunes View Post
I have often wondered whether a superior 'high endurance' plug with some additional clamping arrangement for the fuse, such as a steel spring around the contact clips or even a screw clamping arrangement, might find favour with industrial users.
I doubt so: the world's industrial users invariably use IEC60309/CEE17 connectors - and these don't mess around with in-plug fuses anyway.
G6Tanuki is offline   Reply With Quote
Old 3rd Jul 2019, 3:06 pm   #59
The Philpott
Octode
 
Join Date: Aug 2016
Location: Colchester, Essex, UK.
Posts: 1,784
Default Re: 13 amp fuse for 1.5mm mains flex?

A couple of additional perils from the East are: 1. The occasional wrongly marked flex which purports to have safe CSA for the use in question, but in fact has much thinner conductors. 2. Copper plated Aluminium conductors. Identified under examination by bending individual strands. Copper ones bend, Aluminium ones try to spring back. Dubious results are confirmed by putting the strands in a flame. (Aluminium disappears.)

Dave
The Philpott is offline   Reply With Quote
Old 3rd Jul 2019, 3:13 pm   #60
broadgage
Octode
 
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 1,323
Default Re: 13 amp fuse for 1.5mm mains flex?

I suspect that that there is a growing acceptance that 13 amp plugs and sockets can not reliably carry 13 amps long term.

Most new domestic appliances are now limited to about 10 amps. The main exception being kettles, these are used so briefly that a full 13 amps is fine.

Electric immersion heaters often use a full 12.5/13 amps for many hours at a time, and it is now generally accepted that they should not be connected via 13 amp plugs.

Electric cars often have the facility to charge rather slowly from a standard 13 amp socket, it is recommended to limit the input current to 10 amps in such cases to avoid overheating.
broadgage is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 3:56 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright ©2002 - 2019, Paul Stenning.