Chinese fuses

[Chris]

Hi all,

I bought a load of 5A fuses off ebay some time ago and have just got around to testing them (I test *every* electrical item I buy off ebay these days). These are the typical 250V jobs you find in 13A plugs. Anyway, cut a long story short, I put one of these fuses into the plug of a 2 bar electric fire (2kW) and it hasn't blown. I know these things are far from precision at the best of times, but I'd have thought it should have got 'phut' straight away with this amount of current draw. The question is, I suppose, at what point should a known-good genuine 5A fuse blow?

Ta.

[Chris]

Let's try this again:

[Andrew Gabriel]

That's a current of 8.333A, or 1.6 times the fuse rating.

A BS1362 fuse must *not* blow within 30 mins at 1.6 times rating (nor within 60 mins at 1.4 times rating).

At your 1.6 times rating, it might never blow (but it will get hot).

A BS1362 3A fuse *must* blow within 10 mins at 2 times fuse rating. (The standard only gives 3A and 13A trip curves nowadays - other fuse values have to be interpolated.)

The fuses should be marked BS1362, and also ASTA. See:

Unfortunately, the marking alone is no guarantee they really conform to the marking.

[Dave Plowman (News]

Sounds a bit like testing matches. ;-)

[tabbypurr]

Sounds correct.

NT

[Adrian Caspersz]

The local independent pound shop has a card of 20 brightly coloured chinese special flat car fuses offered for a pound.

I had a look closely at each 5A 10A 20A rating fuse - they are identical!

Around here trading standards would only do something about that if someone buys the item, burns up their car and complains. I am not silly enough to buy them...

[Cursitor Doom]

There's far too much of this dangerous, sub-standard rubbish finding its way into the supply chain AFAICS. Loads of tear-down vids on YT illustrating the extent of the problem. Frightening!

[Brian Gaff]

There was a tv program all about dodgy imported fues, some like yours are just incorrectly specified, some that should be filled with sand are not and hence blow straight away. How can you tell which are genuine, very difficult as they are so good at the cosmetic finish. Brian

[Another Dave]

The BBC run a program called Fake Britain. It featured fake fuses some time last week. Very frightening. Apparently (and this was news to me) all tubular fuses of the type you refer to must be packed with sand. None of the fakes were and this apparently makes them explode, burn your house down and other horrible things. I can't remember the details but it certainly put me off buying cheap fuses.

Another Dave

[Chris]

Thanks. I found it here:

The fuse problem is all in the first 10 minutes, which is handy if you're pushed for time.

[Mr Pounder Esquire]

I can't remember the last time I changed a fuse. Got a change bag full of them in my tool box. I've had them for years.

[Andrew Gabriel]

I worked with a fan heater at an event in Reading a few months ago, which was brought in after the fuse blew, but failed to disconnect. This was a fuse with no sand, although in this case it was a very old one which predated having to meet BS1362 (and it didn't claim it did).

The fuse had blown, but without the sand, the arc inside it wasn't quenched, and current continued to flow in the arc plasma. The plasma was fed initially by the vaporised fuse wire, and then the vapourised fuse end caps, and then vapourised bits of the plug, with the heater acting as a ballast to keep the arc going without blowing an upstream fuse.

There was actually nothing wrong with the fan heater - the fuse had initially blown with old age (and possibly overheating with a poor contact). The plug apparently lit up really brightly, until someone plucked up the courage to reach over and turn off the socket. The plug was coated over the inside around the fuse with a condensed copper film when I opened it.

This could easily have started a fire, if there wasn't someone nearby at the time to switch it off. Fortunately, this is very rare.

[tabbypurr]

Really? Did they by any chance bypass the CU MCB for maximum journalistic effect?

NT

[pamela]

Seems that weighing might detect one of those counterfeits:

"Counterfeit/copy fuse links may contain no sand filler or the fuse element inside might be bent, look unusual, or be loose; the metallic end-caps may be poorly secured. The best indicators are the colour of the ceramic body and the weight (and therefore the amount of sand filler). The ceramic body material is usually much whiter in the fakes, and any fuse weighing less than 2.2 gram should be considered suspect as fuses with no sand will weigh between 1.7 and 1.9 grams"

htpp://

[Harry Bloomfield]

Brian Gaff used his keyboard to write :

The ones marked as Busman, withdrawn by one of the pound shops I think..

[Chris]

I don't doubt your figures here, but given this is the case, I can't see what the logic is. Those blow times and overspec allowances seem positively dangerous. Might as well just use a bit of old tin foil instead (like my dad used to in the 1960s when a fuse blew).

[Dave Plowman (News]

Are you sure? I've seen some that do look the same at a glance (apart from the plastic colour) but the fuse part is actually a different thickness - but looks the same height, as it were. In other works, it's not round but rectangular.

[Mike Tomlinson]

En el artículo <nr79iv$516$ [e-mail], Harry Bloomfield <harry.m1b [e-mail]> escribió:

Bussmann (which is a reputable manufacturer - these fuses from Poundland are counterfeit).

They are noticeable for missing the ASTA symbol in a diamond and the BS kitemark. One way to identify them.

[The Natural Philosopher]

The main purpose of a fuse is to get hot and melt in a safe way somewhat before the hose wiring does and so prevent a fire.

Its not there to protect your electronics

[Simon Mason]

Don't buy Chinese corn cob led lamps - they're lethal!