ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades In the name of safety

Following rules is quite right (in most cases I guess ) but rules have to be made by someone... however, common sense doesn't seem to be the strong side of lawyers and politicians in any country of the world (if they have it, they certainly don't like to apply it!).

TR, I think you've hot the nail on the head there.

No longer is the emphasis on 'making things work.' Rather, it is a desire to 'be beyond criticism,' or to have 'met requirements.' There's an overwhelming attitude that everything is interchangeable.

What fool would make, or buy, a $10 item when theres a $1 version available?

My answer? The same "fool" who buys a $50,000 BMW in preference to the $5000 Yugo.

Buy Rags you get Rags I was told when Young & Theres a lotta Truth to that statment.

The old, and indeed the current, British regulations are a bit fixated on the notion that appliances MUST be protected by quite low rated fuses to prevent fire due to spontaneous combustion of cables.

This led to a situation in the old BS546 system (the old round-pin British plugs) where small appliances, with thin cords e.g. radios, lamps etc had 2 or 5 amp plugs which were connected to socket outlets that were on 2 or 5 amp circuits and so on. Each plug was incompatible with every other socket, preventing someone from 'accidentally' plugging a 5amp appliance into a 15A circuit and so on.

The practice elsewhere was to assume that appliances could survive a 15 or 16Amp fault without major problems.

BS1363 basically allowed the rigid British over-current protection methodology to continue in an era where people needed more than one socket outlet per circuit.

i.e. each appliance is individually fused by the plug, and the fuse is rated appropriately for each situation i.e. 1 to 13amps

The reality however is that people tend to fit a 13amp fuse regardless. So, it's not a heck of a lot safer than a 16A radial system.

I do remember an ancient UK reel tape recorder with an insanely small flex, maybe something equivalent to 0.35mm2 or maybe even smaller. It looked like the wire commonly found inside radios connecting 9V batteries to the board.

The general idea is that the appliance limits the load, so overload doesn't need to be taken into consideration for appliance flex sizing, and short circuit protection can be much higher than overload protection. That's why most regs. allow you to run 0.75mm2 flex off a 16A circuit.

I'd really love to know what the wiring world might look like in 50 years.

If I recall correctly, it's the 2000 revision of AS/NZS 3112 that enforced the transition to insulated pins by 2005. It was followed by the 2004 revision which upgraded the strength requirements for the pins, and I'll admit that most of the newer plugs aren't too bad (although it's obviously still impossible to match the full strength of solid uninsulated pins). Still, it was a typical case of politicians acting before they think.


I have to admit, I find it funny that you say that when you say on your personal website, in the page on building replacement resistance cords:


You acknowledge that its dissipation is 32.4W (0.3A through 360R;) over 1.8m, which gives 18W per metre of cord. While the worst-case resistance of 0.02R; per metre of 1.0mm² (32/0.2) flexible wire (with tinned conductors; with bare copper, as is usually the case, it's a little lower), counting both active and neutral, and accounting for a 16% resistance rise from 20°C to 60°C, gives a dissipation of 4.64W/m at an accurate 10A, or 5.6144W/m at most if you allow for 10% above the nominal current (11A actual).

But for what it's worth, I don't think it's under-rated per se. It's just the result of a typical bureaucratic compromise regarding the designated room temperature, which the previews of IEC 60320-1 and 60320-2-2 state as "not normally exceeding 25 °C, but occasionally reaching 35 °C" (whatever we're supposed to make of that), and presumably the same applies to the official cord ampacities. But I expect that upsizing the cord conductors to 1.5mm² (10A) and 2.5mm² (16A) would be enough to reliably operate those connectors at 40°C ambient (especially given that the copper wires act as a heatsink-of-sorts for the contacts). Still, I wouldn't suggest officially adopting such an upgrade until they stop bundling yet another cord with each new PC/TV/etc., or it would result in even more valuable copper ending up in landfill.


It seems to depend on who made the particular plug, whether it will break or not. The one NEMA 5-15 to IEC (60)320 C13 cord that made its way into my stash, made by I-Sheng (who, judging by the sheer quantity of cords I have from them, are one of the largest manufacturers), has quite a solid ground/earth pin. Incidentally, I also have a batch of cords they made in (seemingly) the early insulated-pin days, so I got one out to compare – it's just as strong as any of the post-2004 models. So it looks like they, at least, are more competent than the politicians.

LongRunner,

Aussie240 hasn't logged into ECN for 10 months.
The post was made in Nov 09.

You revived and posted in a 6 year old thread.