The shrouded earth pin is indeed unusual. However, is there actually an earth wire in the lead? The power supply probably doesn't need one. Many such devices have a 'dummy' plastic earth pin (just to open the shutters in the socket).
However, the other end of the mains lead looks like a three-pin IEC. If the earth pin isn't connected, then a danger would exist if this means lead were to be used elsewhere for some other application, where an earth IS required.
Completely illegal plug.
It was one of the things Trading Standards were extremely hot on, at least before the cuts. Instant impounding of all stock.
Perfectly legal to use. Not even a PAT test failure. Illegal to supply an appliance with one though, even second-hand. Illegal to posses a stock of appliances with them, with the intent to supply.
I did at about age 4, long before shrouded pins.
However, long before shrouded pins, plugs had to be molded such that you could grip and unplug them without wrapping your fingers around the back to the pins. There's also a minimum distance between the pin base and the side of the plug (more so than the one in the photo has).
In message , chris French writes
Reading that sellers feedback there seem to be a number of items that have "blown up" MMMMMMMMMMMMmmmmmmmmmmmmmmm !!
They are mostly made in China for the Hong Kong market. They are just as illegal in Hong Kong as they are here, but the flow of illegal goods was not controlled effectively enough to prevent manufacture.
Surprises abound on the topic of electrical wiring.
According to Leeds Trading Standards it is perfectly legal to sell appliances with American mains leads of the wrong colour, and rated at
110v as long as there is are instructions somewhere (on the box will do) as to how to fit a UK flex should replacement be attempted.The above in respect of the dreaded GHD hair straighteners which gave my daughter an electric shock, and almost turning our house into a giant firework barbequeing the lot of us.
DerekG
ICBW But I think the setup tends to be protected by some sort of thermal / overcurrent device slipped into the transformer windings. Maybe something similar applies to the whole bag of mashings here.
The original and ubiquitous "Muffin Fans" were unfused but were impedance protected and could not draw excessive current.
DerekG
I have had a few of those fail over the years and I have yet to find one fitted with any sort of fuse. Usually they do at least have a thermal link in the transformer wiring, the fuse is the usual point of failure.
Andrew Gabriel laid this down on his screen :
I thought I read or heard something about it being an advisory in a PAT.
The purpose of the fuse in a 13A plug is to protect the flexible cable which has a current carrying capacity much lower than the 32A fuse or MCB in the consumer unit. Any protection offered to the appliance is only a marginal benefit. There is no requirement for devices such as wall warts to be fitted with BS1362 cartridge fuses.
A 3A fuse will cope with a load of 750 watts. If your wall wart developed an internal fault some of its internal components would probably "fuse" long before the 3A fuse blew.
Mike Clarke used his keyboard to write :
I didn't know that, but there is nothing to prevent them fitting a non-replaceable 100mA fuse inside the unit, rather than their relying entirely on the transformer to over heat and melt the thermal fuse.
What would the advantage of that be? Relying on the transformer to melt the thermal fuse seems simple, reliable, and effective to me.
Martin Bonner expressed precisely :
It would not provide protection to any components in circuit before the transformer.
I had one of those on a transparency viewer from ebay - totally crap and replaced with a proper plug.
CE, standing for China Export :)
What did you have in mind? Many linear wall wart style PSUs have the xformer wired directly to the mains input - there are no components before it.
You sure about that?
Not even a thermal fuse?
Yup... got plenty of them here...
The fuse is often built into the transformer.
Never had a problem with 2A and 5A plugs or the clock connectors.
Indeed they are, but that is the mechanical position, I can't recall seeing a thermal fuse fitted at say the mid point of the primary windings. It will be electrically on the end of the winding, so even if the mains is terminated onto what appear to be the transformer terminals, one of those terminals will connect directly to the thermal fuse and thence to the windings proper.
There is no need to protect the transformer terminals, but in those circumstances, if the thermal fuse rating and constructions are selected properly, the transformer windings and the transformer itself are protected.
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