Wylex RECSW2S

If you want to emulate the BS test, you need a lamp dimmer and a low voltage transformer - the old style halogen lamp transformers are good and a short length of nichrome wire like the sort of thing in the open would heating elements of yesteryear (available on ebay in short lengths).


The brightness of the wire can be adjusted with the lamp dimmer.

I agree with DZ here - passing the test in the sense of not flaming when touched by the hot wire is all the makers have to do, and that does not make it safe, or even show the test is appropriate for the problems that can arise in  that sort of equipment at all.


BUT,  just pass the test is all the makers will do, as if they go beyond, their product is then more costly, and they will  lose business to those who do the minimum. In terms of minimum, in some parts of the world clear bodied MCBs  and so on are available, that I am told, are very flammable. Probably important however in some less regulated places to see what is inside though, harder to fake. (and educational )


Consider the tragedy of the cladding at Grenfell - it had been tested to, and passed,  completely unsuitable tests, which had been deemed acceptable by customers who did not really know what the standards involved, , because the letters BS XYZ make everyone feel good. (and partly also because the standards are quite pricey for what they are, so most folk in the supply chain do not have a copy, but that is another matter )

Understandably reducing the amount of toxic flame retardant used willy nilly in plastic cups and cutlery makes sense, I'm less clear that the same argument should be applied to something like an MCB, which is not going to be ingested, but at the plastic moulders, having one batch of ABS flakes or whatever, rather than paying more for an extra one for electrical stuff  that needs special handling is attractive.

Mike.

BUT,  just pass the test is all the makers will do, as if they go beyond, their product is then more costly, and they will  lose business to those who do the minimum.


I think that we are all guilty of this, as we all shop around for what we perceive as the best price.


Regards


BID

True BOD, but perhaps not good. As to the plastic, I don't know if this was the choice of the raw material supplier or the customer. It may not be the problem at all, it could have been on cost. But one can see that the regulations changing (as shown above) will have unforeseen effects. Banning this retardant may be for good reasons (although even the Green website seems not very sure) but the change which the original plastic compounder would probably find from the retardant supplier, is very unlikely to be passed down the chain, or quite possibly no suitable alternative is available anyway. Fire retardants are quite complex, often contain complex halogen molecules, and need to be compatible with a polymer mix, not damaging any of its other properties. Not really the realm of an end-user, and easily overlooked. Such things are hated by many other groups, particularly environmentalists who do not know that combined halogens are rather different from releasing Chlorine or Bromine vapour as a chemical weapon. You will find it is now impossible to buy medical iodine retail, although the alternatives are available easily (Germolene etc.) Older people like that which they know.


BS7671 changing also has negative effects sometimes, I suppose it is a fact of life. The chains of events are interesting, and the regulators need to take notice and understand the effects before changes are made.

Well I did the sample on a hot hob test. The sample expanded a little, went soft and did not catch fire or produce much smoke. Does anyone know how to remove a hard plastic type blob (like dried chewing gum) from a cooking hob?


Z.

In this case reduce to carbon with a gas torch perhaps.

Or freezer spray and mechanical shock. with a sharp knife or similar tool.

Next time use a sacrificial bit of metal on the hob - old aluminium pie dishes and so on are good as impromptu crucibles for things that are sub red hot.(though ally melts ~ 800C so do not over do it) Above that you could invest in a quartz or ceramic crucible.

mike.

The hob test is not all that hot, only 240C or so maximum if a halogen or ceramic type. Yes, the plastic will melt, but expecting a fire is going a bit far. A piece of paper at this temperature is unlikely to do other than become very dry, ignition needs higher temperatures than this, which is not a lot above the moulding temperature. To remove your melted plastic depends on exactly the hob material, but you have the choice of a solvent (cellulose thinner, Acetone etc, possibly petrol depending on exactly what plastic you have used, do not turn the hob on!) or careful use of a Stanley knife blade which should get almost all away fairly well.

It is easy to imagine that radiant heat is at a very high temperature, but this may not be the case depending on the rest. See my reference to the UL-V0 test method above, a gas flame and a big bit of plastic, it must self extinguish fairly quickly.