Available with various numbers of sockets (4 and 6 being most common here in Oz) and with build quality ranging from "excellent" to "total junk"; while having enough outlets fitted to the building itself is preferable, these are certainly very convenient.
Of those I've used myself to date, the clear winner by far is Arista's SPB 1; while the usual cheapos have contacts with almost no spring, which become hopelessly loose in maybe 3-10 years (even with inconsequentially light loading), the pair of Aristas I have are both still going strong. (They were originally in use at Mum's office, then I brought them home recently as they were no longer needed there. One now sits under my PC desk, happily delivering the power to a 600/900/1500W [that's 6.25A at 240V on high, so I'm in the clear as long as the other stuff stays under 3.75A] heater - the Omega Altise OMC15E1 I mentioned before (in the 10th post from the start), to be precise - along with the PC, monitor, and a camera battery charger.) I've posted photos of it here.
At the other end of the quality scale, there's HPM and even worse, some "house"-branded models. So on the scale of A to F, where...
A = excellent
B = good
C = fair
D = poor
E = terrible
F = a total failure
...I would grade the Arista an A, the HPM an E, the "Solutions" (more like Problems) an F, and most of the rest would get Ds.
Anyway, to complete the description of the Arista SPB 1: They're very solid (some of the cheaper ones will flex noticeably if you try twisting them), and although I don't have the type of screwdriver needed to get inside, I can tell that the socket contacts are the type with opposing springy "blades" (Clipsal's 413QC Quick Connect surface socket also uses such an arrangement; the only downside is that if you insert/remove a plug with plated pins too many times, it wears the plating off). The attached cord is, as usual, the Australian Standard equivalent of H05VV-F3G1.0, and measures 0.9m long and is quite flexible (although that was, I think, before the trend to stiffer cords for cheapness hit "critical mass"). So, how long do you think they could last? 50 years, perhaps? While they don't have extra-wide spacing or any other fancy features (beyond a rocker-type breaker that can be switched off at will, rather than the usual boring "push to reset" form), I'm unlikely to bother gambling on someone else's power-boards just to fit in bulky plug-packs; I'd personally just obtain, or make up, an extension cord of a suitable length. (They're sure to be well-protected with the power-board's circuit breaker on top of the house's, and the quality of the hardware will always be far more important than adding 1 or 2 more contact sets than someone's posted arbitrary limit; my limited experience with ready-made extension cords, for what it's worth, has been OK.)
One problem remains, though: I need more than 2 power-boards, at least until the next major upgrade to the house wiring. When that's solved, I'll post an update (or if any of you have some handy info, add it here).
Now for the general comments As occasional overloading of them is inevitable, they have to be protected in some fashion. To my knowledge, it works as follows:
North America: The unit is equipped with a resettable thermal circuit breaker, like the Australian models (although the American ones are for 15A, with a correspondingly heavier input cord).
Continental Europe: They are built to carry the full 16A (with a 1.5mm≤ input cord to suit), with the house circuit breaker being set for 16A or at the very most 20A.
United Kingdom: Their's just rely on the required 13A plug fuse, although many fuses are known to be very "forgiving"...
Trouble is, there's a huge loophole in the system - namely, that 2-way adaptors without OCP (and some functionally similar items - such as extension cords with "piggy-back" plugs, and at least in theory the "Y"-cords sometimes used with PCs) are still allowed down under (and 3-way versions in the USA). Combine them with a suitably powerful set of heaters* (or other high-drain appliances) and you can end up with one hot extension cord (especially if you choose a 20A circuit with a less responsive fuse, instead of a modern circuit breaker)... Ironically, though, they would actually be reasonably safe to use downstream of a power-board, despite some of those comical PSAs.
*Then again, using more than 2400W of resistance heating would be quite expensive anyway...
I had a 4 way plugstrip I can't remember the make but it was a good one none of your cheap rubbish even that overheated when I had a 2 kilowatts heater and a couple of small electronics items plugged into it yet it said clearly max load 13 amps at 250 volts the load I had on it was no more than 10 amps. I now never use these for anything other than small items 2 or 3 amps max any heating loads get plugged into there own outlet
Actually all but the most expensive continental European power strips have no overcurrent protection whatsoever and rely on the MCB/fuse that protects the house wiring. Many also only have 1.0 mm2 flex because flex in free air has a higher ampacity than cable in walls but I think in theory power strips with <1.5 mm2 have been banned in Germany recently.
Some are incredibly cheap. Recently I wanted to use one from the 90s I'd been given for free and it didn't work at all! Turned out the plug pins and socket contact were bare brass and had tarnished enough to keep any current from flowing! I think OVE IEC 60884 actually requires brass to be protected from oxidation but not all manufacturers conformed to the standards. I think this particular one is from a well-known German brand that is said to mostly re-label OEM stuff (although their products are decidedly designed specifically for them rather than generic) and back in the 90s had a reputation for notoriously shoddy extension leads. These frequently ended up on construction sites where the plugs and trailing sockets crushed under the first work boot they met and were then "repaired" with paper masking tape etc.
Proper power strips last for decades, I think the oldest ones I have are from my grandparents and date back to the early 60s.
My brother recently handed me a power strip saying: "That doesn't sound normal, does it?" while shaking it. There were definitely small parts rattling around inside and I noticed one end was slightly cracked open so I pulled a little, just with my fingers and not much force. The whole strip cracked open and all the guts fell out - the contacts had only been held in place by thin plastic studs that eventually broke and rattled around inside the power strip. If you'd kept using the sockets I'm fairly sure the plug pins would only have made contact on one side any more, a serious fire risk. I don't have my camera at the moment but I'll definitely take pictures!
It's also one of those cheap 1.0 mm2 3-way power strips.
My understanding is that the condition for running 16A through 1.0mm≤ flex (or 10A through 0.75mm≤*) is that it must not be coiled up - which in turn limits the allowed length of the cord to 2m (at least for the IEC 60320 cordsets) (as they know it's inevitable that people will coil up longer cords). But I don't think Australian standards would let you use anything less than 1.5mm≤ for 15A either; nor am I aware of any IEC C19 cords actually made with 1.0mm≤ (although C13 and C17 with 0.75mm≤ are done all the time).
*Well, running the numbers suggests that if 1.0mm≤ flex can carry 16A under optimal conditions, then 0.75mm≤ could even do about 13A in the same scenario - although only the British and Danish outlets have that rating, and at least in Britian you're supposed to use 1.25mm≤ or 1.5mm≤ for full current.
In Australia 0.75mm≤ cores seem to be accepted for C13 and C17 cords even longer than 2 metres. Occasionally they even use the equivalent of H03VV-F (light-duty insulated), which I understand is against the IEC's intentions. I've never seen 0.75mm≤ flex in a ready-made extension cord or power strip here, though...
Anyway, is there any indication of who made that junker? And is it even certified? (Frankly, I'd hope the answer to the latter question is a "no".)
Millions of these blocks are in use in UK and in practice I don't think too many problems arise. Most are used for very small loads, e.g computer, router, printer, desk lamp, telephone charger etc, or for clusters of audio/media entertainment units, so electrical stresses are very small. Whilst the blocks are obviously open to abuse the 13 amp plug fuse does protect from serious overloading. The principal hazard if used for heavy loads is, in my opinion, from the cheaply produced contact arrangements. These are typically just bent up brass strips with little spring pressure and can soon overheat. As for price, 4 way units are available from reputable suppliers, (CPC/Farnell), for around £2.
Here are the pictures. Unfortunately the offender was actually made by a rather well-known company and had an OVE mark!
Here's the manufacturer logo:
I recently had problems with another power strip. This one came from a bundle of extension leads and power strips someone wanted to throw away so I know nothing about its history. That was a rather mixed bunch, some decent extension leads in excellent condition and some homebrew versions with conductors squeezed between plug halves, loose screws, overheating etc. This one was made by Kopp of Germany (or OEM'd for them, it's unclear whether Kopp actually has any production facilities) and sold until about 10 years ago. For household use these strips and matching extension leads are OK but they tended to end up on construction sites where they quickly met a horrible fate - the plugs and trailing sockets are relatively brittle and crushed under the first work boot, only to be "repaired" with paper masking tape. The pins are hollow brass and can tarnish rather badly. This one is bad enough that it didn't conduct electricity any more when I first tried it! I plugged something in and it flat out didn't work! The sockets' earth scrapers are as bad and I don't doubt the contact springs inside the sockets look the same. It's also only 1 mm2 but the flex is 5 m long.
Wow, that Legrand strip is just epic failure; from the looks of things, the small cord is the least of its problems.
I'm not sure exactly what it takes for the brass to tarnish that badly as happened to the Kopp strip, but in Australia there's no specific requirement to protect brass (as far as I'm aware) - although most moulded plugs nowadays have nickel-plated pins anyway. Many rewireable plugs here have nickel plating on only the earth pin, which seems to be just to make it stand out visually; on many older plugs, all three pins were plain brass.
The IEC 60884-1 (Schuko standard) requires brass contact surfaces to be protected from corrosion so the Kopp plugs and sockets were never fully compliant (the 60884-1 was also adopted as a nationel OVE standard). Newer Kopp plugs also have plated solid brass pins. The older ones were hollow.