Hello and welcome to the ECN-show.
Tonight we talk about extension cords...

What type of extension cords are used in your country? Do you feel that they provide an acceptable level of fire safety?

Cross sectional area/wire gauge used?

Recently, $1 cords similar to the one below have shown up in Sweden. Rated 2.5A with .75 mm2 cord. Are these used in Austria and Belgium too?



I bought one of these at IKEA some time ago. As $1 for a 10 meter extension cord sounded too good to be true and it lacked CE-mark, I couldn't resist the urge to cut it open. To my surprise, it revealed both shutters, strain relief and an otherwise acceptable design, though the wires had the thinnest sheating I've seen.

Too bad I haven't got a digital camera...

[This message has been edited by C-H (edited 10-31-2002).]

Our "standard" light-duty household extension cord comes in 6', 9' and 12 or 15' lengths.

It's a single-insulated length of SPT-2/16AWG zip-cord with three female receptacles at one end and one moulded polarized two-pin plug at the other.

They are all either made in China or the Phillipines and look roughly like this (photo was stolen from a Chinese manufacturer's website)



The manufacturer's website is http://www.asiancord.com and the brand stamped on the cord itself is YUN.

These things are actually sold under various importers' names here in New York City variety and discount stores. YUN also makes other "budget" electrical accessories (like three-way adapters).

Back in the 1970s/early 1980s, the extensions used to be 18 AWG (equivalent to .75mm european cord)! I still have one at home in my junk bin.

Can you imagine three appliances running off a 15-foot length of .75 mm flex? Needless to say that these things caused a lot of fires and are no longer manufactured in 18-gauge versions although many are still in use (I've "confiscated" and replaced a lot of them at my relatives' :-) ).

[This message has been edited by SvenNYC (edited 10-31-2002).]

I knew our 13A fused plugs were useful for something, yes protecting cords.

Extension cords are available in various lengths, fused appropriately;
0.75mm: 5A fuse.
1.00mm: 10A fuse.
1.25mm: 13A fuse.
1.5mm: 13A fuse.
Some of the better ones have built-in overload cut-outs on the socket ends to prevent overloading.
Most of the extensions on sale nowadays are 10A or 13A rated.
Biggest fire risk comes from people using heavy loads on 25M cable reels without fully unwinding it.

We never see anything like that illustrated in your post, C-H.
It looks like a piece of junk.

Personally, I think that they are ok as long as you put the right plug in it. The problem starts when people try to put adapters so that they can stick in it the shucko plugs and the like.
These are less common then these, though.

[This message has been edited by Belgian (edited 11-01-2002).]

Same stuff available verywhere in Austria.
Other variations are the romanian 1 mm2 cord I told about earlier. "Real" extension cords are Schuko, sometimes screwed-on plug and receptacle, not molded or (worst case) just snapped together, 1.0 or 1.5 mm2 cord, correctly labelled. The ones for heavy-duty site use also have tough rubber sheathing instead of PVC. With screwed cord caps it's good to check the terminal screws of new cords though. I've encountered some that weren't tight.
When I was in America I've seen various ways to abuse such extension cords. One way is to convert it to a 6 outlet one. Take 2 of these, cut the cord somewhere in the middle, throw away one of the pieces with a plug, take the three remaining pieces, twist the wires together and warp the result with lotsa black electrical tape (REAL expert would take silver ducktape!) and voila!
Finally staple everything to the next wall.
Seen in at least one kitchen, a teacher's office at school,...
Other way I've seen: You know these (I think 6-way) adaptors that fit a duplex receptacle? Take 2 $1 extension cords, plug the tap into these 2 (ground gets lost somewhere on the way), resulting in 10 outlets. Then hook up a grounded 5-outlet extension strip to the tap. 14 outlets instead of 2 (the only ones in a 9x9 ft room). I can post a pic of that mess.

Sven,
I've seen cords made by Ningbo here to. This makes the "different plugs in different countries"-thing even more laughable. The plugs are all made in the same Chinese factory, and then distributed around the world. Then they sell us adaptors to convert between them...

David,
Cable reels are required to have overheat protection. I would have thought this to be the case in Britain too?

[This message has been edited by C-H (edited 11-01-2002).]

Wow, that's downright dangerous, having an
extension cord (or flex, as we call them over here),without an Earth conductor,is it legal?
Over here, we use 1.0mm2 2core+Earth in our flexes, as a minimum, this is for domestic use only(This is light-duty insulation).
For any commercial area, we like to use
1.0mm2-1.5mm2, with Ordinary-grade insulation, depending on the length of run,
however, the use of flexes is discouraged,in this type of environment, where people can trip on them, we would normally install more
socket-outlets.
For Industrial sites,there is a requirement to have 1.5mm2 flexes, with Heavy-Duty insulation, this is coloured Yellow, come on to a worksite over here, with an Orange cord, and see what happens.

No. I've seen a few cable reels with it included, but it's not very common here.

Trumpy,
I don't think the ungrounded/unearthed extension in C-H's post is as bad as you might first think.

The socket end is designed to take only the 2.5A two-prong Euro plugs. It won't accept the grounding-type Schuko or French/Belgian plugs, nor even the two-prong 10/16A plugs. If somebody uses an adapter on it to connect such a plug, that's another matter, but we can only so far in protecting people against their own actions.

Many older American 2-wire extension cords could be used with a 3-prong plug, the ground prong just floating unconnected. The newer-style extension sockets have a wider face to prevent that.

The extension cord tangle I mentioned is now up on the photo discussion section.
All cable reels I've seen here (except for the small 5 or 10m types with only 2 outlets) have overheat protection.
However, they can very well be a nuisance. I bought a construction grade 50m metal reel, on which the overheat sometimes trips as soon as a 9W fluorescent is plugged in. A kick against the reel would help then. Guess I should've asked my money back.

The cord I pictured above is a new and yet uncommon type. The standard type you will find in the supermarket still is the ungrounded type that accepts both grounded and ungrounded plugs:



Do you find these in Belgium too?

Note: As you can see the sockets are turned 45°. This is to allow modern angled grounded plugs with cord guard to be inserted. (Like the one in Belgian's picture) If the sockets were in line, the cord from the plug in the middle socket would block one of the other sockets.

[This message has been edited by C-H (edited 11-03-2002).]

No, these are not allowed here since it lets you put a grounded appliance without being connected to the ground.
I can't see for sure but it looks like your plug will not fit in a grounded socket here.
Why then 45°. Why not 90°? Like this one:


[This message has been edited by Belgian (edited 11-03-2002).]

Correct. It will fit a grounded schuko socket with some force, as the moulded plug is slightly flexible. This will destroy the grounding of the socket, though. Therefore, the Belgian sockets are safer.

I've just sent the Swedish Electric Safety Authorities a stern e-mail where I point out to them that they are lagging way behind rest of the world. Among a lot of things I asked them to make the above ungrounded extensions illegal.

The 90° have begun to make their mark here. Take them apart and I think you will find that you need more copper (or is it brass?) to build a 90° than a 45° socket. (Haven't taken a 90° apart yet, but I intend to some day)

[This message has been edited by C-H (edited 11-03-2002).]

Geez, I thought ungrounded extensions were available only in hungary!
Also I've never seen ungrounded extension strips like this!
Guess a shopping trip to Sweden is on my schedule!

We have also find these types here:

It can get messy with 9 or 10-way extension strips:



This brings me to another question: What is the rating of the little flat Euro-plug in Belgium and Austria? (Here it's 2.5A, but I know it's more in other countries)

Tex: What are you going to use the ungrounded strips for? Do you as a central-european have any knowledge of the systems and plugs used in Hungary, Czechia etc.?

[This message has been edited by C-H (edited 11-03-2002).]

Here it's also 2.5A. I've never seen 9way extension strips here!

Euro plugs are rated 2.5A here too. However, I've seen 1200W hairdryers with a Europlug.
The 9way strip is exactly what my computer is plugged into, only mine is black.
Hungary has Schuko plugs and now standard European color codes, used to have black/grey/red. Hungary is the only country I know having used aluminum in residential work, apart from the US. (I once took apart an old system that was all wired with 1.5 mm2 aluminum wire in conduit, don't know the ampacity, the panel was long gone. However, there were ground wires everywhere.)
Czech republic, Slovakia and Poland use French style plugs.

BTW, we have adaptors allowing one Schuko receptacle to take 3 Euro plugs. However, they're built so cheap that they'd also take old ungrounded plugs.
They come in various colors, Kopp brand, no approvals (OVE, VDE or else).
Italian receptacles also take old round plugs.

>BTW, we have adaptors allowing one Schuko
>receptacle to take 3 Euro plugs. However,
>they're built so cheap that they'd also
>take old ungrounded plugs.

How the h**k do you do that? We have 2, 3 and 4-way splitters, but they sure don't take anything but Euro-plugs. (But we also have ungrounded splitters designed to take all plugs, of course.)

How 'bout Hungary and grounding? Are Schukos common?

[This message has been edited by C-H (edited 11-03-2002).]

Simple. They have almost flat faces with six holes, taking 3 plugs in avertical row. Size and shape like a Schuko outlet with faceplate. Lowest plug goes slightly downwards, middle plug is straight horizontal, upper one points upwards. Top and bottom position won't take a round plug because the face isn't flat, but the middle one does.
I don't have seen many houses, but even older ones that were wired prior to the 1970ies had red ground wires and Schuko receptacles everywhere.
In one of those houses I found the most creative piece of 5-way switching I've ever seen. Dining room in a small castle has 4 doors. One switch per door, 2 switches at one of the doors. 4 wall sconces. I don't have even the slightest idea how this was wired, but it enabled you to either switch on 3 lights, 1 light or all 4, but only if some of the switches were on and others off, and if some switches were off it was impossible to switch on the lights from any other point of the room. Complete chaos.

C-H:

Don't the large round ungrounded plugs have notches and contours cut out in them to bypass the ground contacts on Schuko and French sockets?

I have a high-intensity photography lamp that has such a plug (my mom brought it over from Germany when she moved here).

The plug is a 16-amp two-pin ungrounded (with the thick pins) and even has a fuse in it!! Go figure.

Sven:
>Don't the large round ungrounded plugs have
>notches and contours cut out in them to
>bypass the ground contacts on Schuko and
>French sockets?

Yes and no - double insulated appliances have these plugs. Not used on the extension cords, as it would make it possible to connect an ungrounded trailing socket to a grounded wall socket.

An add-on: They're called contour plugs and used instead of Euro plugs on appliances that draw more than 2.5A. They came up along with the first Schuko receptacles in the 1950ies. Many old radios and tape recorders have them. Euro plugs came much later.
I haven't seen anything but photo lamps with a fused plug. My old 1000W Super 8 movie light has that too.
The ungrounded plugs I was referring to are completely round and have small pins, just like Europlugs, but unsleeved.
Plus the pins were partially split in halves, so if the plug lost contact you just bent them apart and that was it.

Were the holes in ungrounded sockets smaller too?

(Full size (4.8 mm) solid pins on our ungrounded plugs. I've seen old ones with sleeves, but it's not used today)

It depends. Wall outlets had the same holes Schuko receptacles have (nice for inserting contour plugs, but allows plugging in Schuko plugs), the ones used on extension cords have smaller holes, thus accepting only ungrounded and Euro plugs.
The pins of our old plugs were solid the first 5mm where they emerged the case, then they had a small slot. It looks as though they'd been partially cut in halves from the tip with a very thin saw blade. Cheap types didn't have that feature, they tend to slip out of most sockets (remember, all of them are older than 20 years now, they're pretty likely to be worn out at least a little bit).
Oldest sockets I've seen are from the beginning of the 20th century or maybe even earlier, were made of brass and white porcelaine, lokking pretty much like the one posted on the "old electrical parts" thread some time ago. These were usually wired with surface-mount 0.75 sq. mm cord, 2 single sheathed wires twisted around each other, put on porcelaine or glass insulators. If I'm ever going to see such an installation I'll take pictures, maybe I even have some (I think I took a pic of a light switch from 1924 with some cord)

Many types of British 2 and 5A plugs were similar. If a plug was a loose fit in an outlet, you could just pry the pin open very slightly to improve the contact.

As old as this thread is, I have to correct Trumpy on Australia/NZ extension cords:

Under official definitions, there are no (legal) "light duty" extension cords here; by "light duty" flex we mean H03VV-F (circular) or H03VVH2-F (flat), and their dimensional equivalents in AS/NZS 3191. Those only go up to 0.75mm^2, so they can't be used under the regulations for Aust/NZ extension cords (no doubt abrasion resistance is also a factor); therefore, no company here manufactures trailing sockets to fit H03VV-F (much less H03VVH2-F).

For ordinary-duty extension cords (as used in homes or offices), we of course use H05VV-F or the equivalent thereof. Heavy-duty extension cords here mainly use a flex (also specified in AS/NZS 3191) with the same dimensions as H07RN-F, but usually in PVC. "Extra heavy duty" isn't actually a type of flex with still thicker insulation, but just means a heavy-duty flex with 1.5mm^2 (or larger) conductors.

Otherwise, Trumpy is correct that 1.0mm^2 is the basic conductor size (for 10A); with 1.5mm^2 for 15/16A (and it can also be used to reduce voltage drop in longer 10A leads, of course). All legal versions are earthed, too.

The basic type of extension cord here has just a single socket; compared to many other arrangements, this is very sensible, and would be close (as far as reality allows) to fool-proof if it wasn't for the existence of the unprotected double-adaptors ("piggyback" plugs - common on some extension cords - also create the exact same hazard, just in a cosmetically different form).

Yes, I suppose some updates are in order, although most of the posters on this thread are gone now.

1) Italy and France seem to be the only countries that have plugs that are compatible with Euro plugs but have a higher rating (6 A in France, 10 A in Italy). That's what sometimes ends up on cheap hairdryers, although I've seen at least one 1500 W hairdryer with a plug clearly marked "2.5 A 250 V". We also have one with a truly strange plug, the pins are exactly the same thickness as on a Euro plug but considerably shorter - I need to replace that one as soon as possible!

2) VDE now requires all extension leads (except those that only accept Euro plugs) to be 1.5 mm2 or larger, apparently there were too many issues with overheating 1 mm2 power strips.

3) There are extension leads with contour plugs and mating sockets that have plastic "walls" in place of the earth scrapers that should in theory exclude Schuko/French plugs but in reality they break easily. I'm not sure if they even comply with Austrian and German regs but they're sold. Usually they're undersized too, 1 mm2 and up to 20 m long. Fairly popular among contractors of Eastern European descent.

4) Earthing arrangements in Hungary, Slovakia and the Czech Republic (actually that deserves its own thread but I'll quickly comment on that here): some older places in Hungary have sockets for class-0 appliances but it seems they were banned for new work some time in the 60s or 70s. All earthed supplies seem to be TN-C-S with the PEN split near the supply fuses, although there might be TT supplies in rural areas. Old wiring is - scary enough - 1.5 mm2 Al in conduit or cable buried in the walls, in the 1980s they went up to 2.5 mm2 Al. Joints seem to be twisted and taped everywhere, even with newer copper mixed in.

In Czechoslovakia I've never seen a socket without earth, most houses seem to have been rewired at some point. However, all the older installations are TN-C, often wired with Al. A friend's apartment in Prague had 2.5 mm2 Cu socket circuits (two doubles per room) and 10 A lighting circuits wired with a wild mix of 1.5 mm2 Cu and 2.5 Al. I've also seen socket circuits with 4 mm2 Al. Aluminium wire seems to have been widely used in Europe during WWII due to material shortage but most, if not all countries behind the Iron Curtain continued using it into the early 1990s. Apparently in Latvia Al wire was readily available in DIY stores in the early 2000s.

Finally a note on pre-Schuko sockets and plugs (i.e. un-earthed for class-0 appliances): the original design was 6 A with split 4 mm pins and 4 mm holes on the sockets. Later, a 10 A design with 4.8 mm solid pins and corresponding holes on the sockets was introduced. Apparently 10 A plugs were fairly common in Germany but rather rare in Austria but most, if not all new sockets from the early 1950s onwards were 10 A. New installations were required to be fully earthed by 1958 with a transitional phase (for buildings already in planning or under construction) until 1960 but un-earthed sockets were sold as replacements or for extensions of existing installations well into the 1970s. Leftovers could be found in older stores as late as 1990.

A brief explanation on class 0 and un-earthed sockets: class-0 appliances are designed like class-1 appliances with only one protective layer between live parts and exposed metal casings. They were only to be used in "isolated rooms" with no exposed earth potential, e.g. earth wires from either mains wiring or radio/TV aerials, metal water, gas or central heating pipes, stone floors etc. The reasoning was that under these circumstances people could not possibly receive a fatal shock from a faulty appliance since there is no path to earth for a current to flow. This is the main reason why those old plugs don't fit Schuko sockets but vice versa - in an isolated room a class-1 appliance without earth is no more dangerous than a class-0 appliance. In some countries isolated rooms were used much longer than in Austria and Germany, e.g. in Sweden until 1994.

Tex:

As I am 100% not familiar with wiring and devices on the other side of the pond, your post was interesting.

Well, I've already done some real load tests with cords of my own (a few of which I've described in a previous thread on this forum). (I probably ought to assemble a cleverer arrangement than convection heaters for future tests, though, in order to maintain slightly lower room temperatures during Australian summers .)

So, on the basis of those: For cords up to about 10m long, then, our 10A through 1.0mm^2 appears reasonably safe (although up to 25m is permitted, which will be somewhat worse). But 16A through 1.0mm^2 for 20m sounds like a meltdown waiting to happen, if the user isn't thinking.
On the occasion when you need a still-longer cord, then, I would go with a thermally protected extension reel, and/or upsize the wires another step (e.g. 1.5mm^2 for 10A, 2.5mm^2 for 15/16A).

While laid straight, though, the flexes themselves seem to cope well enough with 13A through 0.75mm^2, or 16A through 1.0mm^2 (or 20A through 1.5mm^2 etc.).
I strongly suspect that (most of) the true problem behind the VDE's "upgrade" was related to the inconsistent quality of terminations (which is no doubt severely exacerbated by penny-pinching). But although thicker wires may well keep borderline terminations a bit cooler and survive for a little longer, I've clearly seen signs of localized overheating even inside appliances that do it 'by-the-book' with 1.0mm^2 for 10A (or even lower current) -- and usually while the appliance itself still works.
(For obvious reasons, space heaters are among the foremost victims...)

Rather than continuing to debate over what's "statistically acceptable", I really do think we should be questioning the inevitability of wire terminations continuing to fail at all. See my new thread.

Of course, we can never absolutely rule out the occasional freak accident; but I don't see the need to accept such systematic failure as we see...

At least in Austria and Germany plenty of rewirable plugs failed back in the old days because manufacturers dipped the ends of the stranded wires in solder before clamping them under a terminal screw. The solder moves under the pressure of the screw and the termination then overheats. I'd say that was clearly the issue in roughly 90% of the failed plugs I've seen. Unless I've forgotten a few I've only ever come across one failed moulded plug and that was on an early-2000s dishwasher and the plug failed in 2016, taking the socket with it. The socket was only three years old, decent-quality and tested after installation so I'd rule that out.

Don't forget that there's a very large grey area between a 'comfortable maximum' (IEC 60320 rates that at a pin temperature of 70°C, except for the higher-temperature variants which may reach 120°C or 155°C when further heated by the appliance) and actual meltdown; I've previously run heaters (up to and including 2.4kW @ 240V) through (deliberately long and silly-looking) chains of IEC 60320 C13/C14 cords, to prove the point that it would still work (which it does) .
They are mixed 0.75mm^2 and 1.0mm^2, and none of the flexes themselves get warmer than I'm comfortable with. So far, I've only had one pin actually melt the plastic (which I later diagnosed, by autopsy, as a really bad crimp connection that didn't hold onto the wire at all!), but many pins still get too hot to touch (these are mostly "modern" versions, usually from Chinese/Taiwanese manufacturers).

(But then, surely a 10A-rated connector sustaining a heater drawing 10A is just the basic call of duty .)

I did have one other defective C13 socket, on a molded cordset made by CMA (back in the 1980s, at a guess). This, however, was a completely different fault: There was a bit of stray PVC in the active/line slot. This cordset ran cool while the connectors were properly seated, but the errant bit of PVC carbonized and created a nasty resistive path (releasing clouds of smoke) when I unseated the C13 end under load. And this one was a bit tragic, really, as the contacts themselves looked much more robust than in newer versions. (I salvaged it by cutting off the C13 end and converting it into a short extension cord.)

Apart from such occasional defects, though, the earlier molded cordsets were fantastic (if observed trends continue, they could well provide centuries of reliable service)...
Between the "new" Chinese/Taiwanese versions and decent rewireable connectors, though, I think I'll stick with rewireable (for heavier loads, at least).

By failed I mean "got hot enough to smoulder and turn a crispy dark brown" or even "hot enough to burn holes around the pins". If you look at a white plug and see a brown circle around one pin you know what's going on. I've hardly ever seen that with stranded wires straight under screws (technically illegal according to German VDE regs) so I'm fairly certain the solder was the issue. It's similar to the troubles with household-size Al wiring in screw terminals.

Rewirable plugs and trailing sockets have pretty much become a DIY item here, everything sold in a store will have a moulded plug on it. Of course electricians do use them for repairs and site-made extension leads too but in Germany the general assumption seems to be that repairs are supposed to be made with OEM parts (i.e. if a moulded plug fails or the flex is damaged near the plug you need to replace it with an entire new flex with moulded plug supplied as a manufacturer spare) and site-made extension leads require all sorts of compliance paperwork and testing so it's safest not to touch anything. At least I see that attitude becoming more and more common in web forums.

On that note, here's my latest report:

Just last year, I bought a Kambrook KFH660 (and reviewed it here) -- which as basic as it is, is still a great heater for the price. It's just passed its warranty length, with no functional problems.

However, the pins on its plug already get rather hot when operating at full power.
(Of course, they're nowadays stuck with buying the usual China/Taiwan cordsets; because no Australian company makes them anymore, and using the IEC 60320 C18 inlet -- as logical, and convenient, as that would be -- would expose them to an inevitable frivolous lawsuit, the minute someone plugged one in with a counterfeit cord. )

(I kind of wish they'd also make a 600W version, with a C8 inlet; that would be really cute, and still powerful enough for many small rooms. Too bad that the general public has such an unhealthy fetish for "MOAR POWAH", and oversized homes...)

I'll shortly be buying a few Clipsal 439S, to replace the plugs (on it, and my other full-size heaters)…

(And let me tell you: I've surely taken the environmental high ground, compared to my nearest neighbor who still uses an open fire. Seriously; if those aren't obsolete, then I don't know what technology is. )

Longrunner:

I'm amazed at the details in your review of what sounds like a 'basic' electric, fan forced space heater. (KFH660 via the link)

It looks to me that you enjoy taking things apart and doing a thorough analysis. To satisfy my thoughts, how much time did you invest in doing the take apart & put back together?

I agree, John (HotLine1), it's one thing to take things to pieces and re-assemble them and I'm not trying to be nasty here, but this treatment of a simple heater, sounds pedantic, these things are mass-produced and you get what you pay for, because that is what consumers are willing to pay for, they are cheap and effect a means to an end.
Personally I don't use electric heating at all, as it is too costly here in New Zealand, I prefer an Eco-Fire, log-burner, because that is what I have, sure it's a pain in the arse getting wood in from the wood-shed, but it heats the whole house.

Yes Mike, I’m still amazed at the details. I get spec books along with plans, and there is more details in Longrunners posts. I meant no disrespect either, just would like to know the man hours invested.

Hi im back been absent for a while as had a truly terrible year so far be glad when 2019 gets here cant be nearly ad bad as 2018. Anyhow back on topic Paul UK its interesting what you say about old UK plugs because a while ago a friend gave me a 2amp 3 way adapter I noticed its live pin appears to have half its diameter missing starting just after pin leaves the adapter body now I assumed it had had some sort of accident or something but now it looks like its a deliberate thing if im reading your earlier post correctly. Its made by clang is off white color rated 2 amps 250 volts

PaulUK hasn't been online for many years, does anyone know what happened to him? I searched the web both for his user name and his full name and never found anything.

Sorry to hear about your bad year, hope it'll get better soon!

Hi Texas Ranger thanks to be honest it cant get any worse thats for sure like I said roll on 2019!!