Does this look like 3x 0.5mm² cable? BTW: It came from the land of the dragon - Page 1
Forum section: electronics / general

author: madworm
author_rank: Frequent Contributor
timestamp: May 17, 2013, 08:08:19 pm
content: The IEC plug claims 16A... the wire claims to be 3x 0.5mm²... but it's so thin, like butter spread over too much bread ;-)The IEC plug on other side of the cable is not quite up to spec, it is a born wiggler - and too short.Oh, and it's not pure copper either! That stuff is so.... springy! Doesn't want to stay bent.The resistance of the cable is way too high for copper. According to some data-books the closest match for this thing is STEEL wire.Maybe I should send it to Dave for closer inspection ;-)

author: Unknown
author_rank: Unknown
timestamp: May 17, 2013, 08:13:26 pm
content: Steel is magnetic, copper is not. That's easy to test.

author: Lightages
author_rank: Unknown
timestamp: May 17, 2013, 08:17:43 pm
content: It is definitely steel, and probably copper coated. I have run across this a couple of times too. Use that cable as extra weight in a trash can.

author: madires
author_rank: Super Contributor
timestamp: May 17, 2013, 09:01:55 pm
content: The C13/C14s are rated for 10A and the wire has to be >= 0,75mm². A wire with 0.5mm² may be used for C5/C6 (Mikey Mouse) or C7/C8 (Euro or figure of eigth) which are rated for 2.5A. If you bought that cable from a local store you should return it and tell the store that they are selling dangerous stuff violating safety standards.

author: david77
author_rank: Frequent Contributor
timestamp: May 17, 2013, 09:52:16 pm
content: Wahnsinn...How can it be cheaper to use steel wire coated with copper than the real thing?

author: madires
author_rank: Super Contributor
timestamp: May 17, 2013, 10:10:01 pm
content: Quote from: david77 on May 17, 2013, 09:52:16 pmCopper is about ten times more expensive than steel.

author: madworm
author_rank: Frequent Contributor
timestamp: May 17, 2013, 10:38:30 pm
content: Quote from: madires on May 17, 2013, 09:01:55 pmNah, unless you call Ebay local ;-)It was shipped from a local source, but the seller is from China.The cable belongs to a switch-mode power supply for a LED-strip. I became suspicious right away when I touched it: way too light, way to thin, too flexible... and the power-supply-side plug didn't fit right. Fortunately the LEDs appear to be fine and the power-supply is OK as well. Above 80% efficiency at medium load, and that stays the same even when pushed to almost 2x overload. It's got short-circuit protection as well ;-)Complaining about the cable is not worth the trouble and fortunately I have enough of these in a box somewhere. However I'm certainly glad that I discovered that piece of crap.And I do hope that building-code not only requires insulation testing, but also resistance testing of the wires. I wouldn't want to have stuff like that in my walls. Instant fire!Regarding copper wires... I thought 16A required 1.5mm², but maybe that was solid core... Oh well.

author: madires
author_rank: Super Contributor
timestamp: May 17, 2013, 11:35:03 pm
content: Quote from: madworm on May 17, 2013, 10:38:30 pmFor house wiring you would use solid wire and not stranded wire.QuoteYep, and for long wires 2.5mm² (voltage drop).

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 06:49:43 am
content: Building codes only require the use of type certified wire. If there is a problem you have to take it up with the supplier. Good idea not to buy house wiring on eBay then. For wiring in a wall there are factors for derating depending on cable, wall and conduit, the codes default to a worst case so you need 2.5mm here for a socket outlet and a 20A breaker, 1.5mm is for lighting with a 10A breaker. The older spec called for a 4mm cable for sockets, and 2.5mm for lighting. In all cases the length is limited to 30m as a maximum unless you go up a size or two.Never had the steel wire, though the copper cabling in a lot of premade extension cords is very suspect, failing in short periods with regular use. I tend to buy type certified cord in 100m rolls ( which actually meet standards) and plugtops and socket outlets that are robust. Those are larger, but do not fail. For some I use steel socket outlets for industrial use, they handle abuse quite well, like being used for regular bending and rolling up and out. They tend to work out at about 10x the price of a premade one.

author: amyk
author_rank: Super Contributor
timestamp: May 18, 2013, 11:12:42 am
content: It's not surprising that the connectors on the end of mains cabling are often rated for more than the wire itself. As you mentioned it's for an LED strip (how many watts?) the manufacturer probably chose the cheapest that can carry the current needed for it.

author: madworm
author_rank: Frequent Contributor
timestamp: May 18, 2013, 11:24:23 am
content: Oh, I do understand the thinking of the manufacturer very well.And yes, that cable would probably have carried the current no problem (about 300mA @ 240V when overloading the power-supply to max). The bad plug would have given me trouble though, extremely loose 'fit'.The big problem is that this cable could have been plugged into any other device with a mating socket, possibly a high-power device. And we all know what happens if you push 16A through a cable with 1.6 Ohm. Not a pretty sight and smell.

author: amyk
author_rank: Super Contributor
timestamp: May 18, 2013, 11:37:04 am
content: Quote from: madworm on May 18, 2013, 11:24:23 amThat's why electronics often have a very stern warning in the user manual: use only the provided power cable with the device (even if it's a standard plug).

author: madworm
author_rank: Frequent Contributor
timestamp: May 18, 2013, 12:02:33 pm
content: Who reads manualsSeriously, they should've chosen a low-amperage cable / plug in the first place. Less material, therefore cheaper.Maybe I should start wondering why a supposedly fully isolated power supply needs a cable with a safety-earth pin.

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 12:14:07 pm
content: Could this be what these are for?

author: Bored@Work
author_rank: Super Contributor
timestamp: May 18, 2013, 12:35:55 pm
content: Quote from: Monkeh on May 18, 2013, 12:14:07 pmYea, we all know you have the best, safest sockets in the world, bla, bla bla. But no, your fuses are there because of the ring installation can deliver twice as much current to the socket as a kettle lead can take.The rest of the world specifies that one should not make a power cord out of junk wire. Instead if you use a 10A connection system like C13/C14 you better use a wire capable of carrying that current. Those who don't, and use the equivalent of a wet shoestring instead, are criminal pieces of shit.

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 12:36:52 pm
content: Only in the UK, where for some reason they use a 32A breaker with wire that will cook at 32A unless you put 2 in parallel. Here they allow a 20A breaker for a 16A socket, though I will admit it is hard to find a socket outlet that will handle 16a for long, and the cheaper plugtops are going to melt into a mess into the socket at 16A. The switches are also suspect, 16A yes, but not after 100 operations. For loads like that ( airconditioners) I have been doing a dedicated feed, a local isolator by the unit and a breaker for it in the panel. That does give very little trouble, though I bought a 24000BTU window wall that actually uses half the current of the unit it replaced. Very good improvement in both efficiency and the running costs of a unit that does run 24/7 to cool. New one uses 9.7A, the old one 18A, but the cooling is the same, and it is a lot quieter. Did weigh 60kg, was heavy to lift up into the case after doing the new brickwork, and waving at the guys 2 floors below while doing the piping. Did buy a new hammer to place clips, one that had a hole for a lanyard, just in case..........

author: tom66
author_rank: Super Contributor
timestamp: May 18, 2013, 12:40:08 pm
content: Ring main is supposed to be protected by the breaker, not the fuse. The fuse protects the cable and plug only. Ring main can deliver 32A as well, ordinary plug is limited to 13A, cabling is usually rated 13A or 16A in my experience for heavy duty devices.And the UK does have the best sockets and plugs IMO... I just wish we hadn't chosen that stupid light bulb connector which has exposed live and neutral pins. We could have at least made a bulb like a plug...

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 12:48:52 pm
content: Quote from: Bored@Work on May 18, 2013, 12:35:55 pmWow, you managed to completely miss the point and be an ass about it in the process.QuoteAnd how much current can your circuits supply to a C5 connector?QuoteFunnily enough, we're the same. I never once said this cheap Chinese deathtrap was meant to exist.

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 12:53:15 pm
content: The lamp socket is evolution in action........... The US one has a 50% probability of killing you if you do not disconnect the power when changing a lamp.

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 12:56:38 pm
content: Plug fuses are great, but not much use when the common remedy to a blown one is to buy a new one, invariably a 13A one and place it in. How does the average public know that you need to get the right one, they just go into Tesco and pick up a pack of plug fuses, and put them in until one does not blow ( moaning about the cheap junk that keeps popping on the lower current ones) and the iron works again.

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 12:58:49 pm
content: Quote from: SeanB on May 18, 2013, 12:56:38 pmWell, shit, I guess we'd better make sure knives don't have sharp edges so people don't cut themselves.

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 02:12:05 pm
content: But most are taught from young that knives are sharp, and learn the lesson. Electricity tends to be a single event which does not result in a memory of pain to use next time. It tends to be a one time lesson.

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 02:19:44 pm
content: Quote from: SeanB on May 18, 2013, 02:12:05 pmThen they should be taught, and learn, rather than the world dumbed down to suit them.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2013, 02:21:07 pm
content: Quote from: SeanB on May 18, 2013, 06:49:43 amOf course the wire has to meet specific standards based on the application. Basically we got one for in-wall, one for damp locations (in/on wall) and one for buried cables (outside). The one for damp locations is used mostly, also for in-wall applications in non-damp rooms. The standard breaker has 16A, so 1.5mm² is used primarily. For long wires (around >30m) it should be 2.5mm². And for high current stuff like ovens and cookers it's also 2.5mm² (also for 16A 3-phase sockets).One important issue about the whole house wiring is that old !6A breakers are triggered instantaneously at 80A. So the wire is required to carry 80A for some ms without any problem, i.e. the resistance has to be low enough to allow those 80A to flow in case of a short circuit. Therefore also the flexible cables plugged into the wall outlet need to be 0.5mm² at least (for short cables, 2.5A max). The standard cable for computers and stuff is required to be >= 0.75mm² beacuse it carries 10A max. One has to except that people will mix cables and hence it's better to define a standard and not to allow custom cables.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2013, 02:24:15 pm
content: Quote from: Bored@Work on May 18, 2013, 12:35:55 pmI totally agree! It's much safer to have a standard for detachable cables because people will mix them.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2013, 02:34:05 pm
content: Quote from: SeanB on May 18, 2013, 12:36:52 pmIIRC the ring wiring was choosen to minimize the wire usage (after the war). You can get 3-phase IEC/CEE plugs for 32A, 63A and 125A, no problem :-)

author: SeanB
author_rank: Super Contributor
timestamp: May 18, 2013, 02:37:25 pm
content: Ring wiring here is illegal, a single break is not detectable as a fault, and can cause either a fire or burn out a lot of wiring without warning.

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 02:39:25 pm
content: They don't magically burst into flames because of a break.Ignoring the subject of rings, we also tend to supply higher current radials, which stops the entire damn circuit from going when one lamp blows.

author: madires
author_rank: Super Contributor
timestamp: May 18, 2013, 03:39:09 pm
content: Quote from: SeanB on May 18, 2013, 02:37:25 pmOver here the fairy of electrons would pop up besides you and say "no, no!" if you dare to think about ring wiring :-)No offence meant to my British friends.

author: Monkeh
author_rank: Super Contributor
timestamp: May 18, 2013, 03:42:23 pm
content: Never said I supported the use of ring final circuits. Although they have their place, it's not winding their way around my house willy nilly.Ring mains is another thing entirely (nobody grasps the difference, though).