Electrical advice please

securityguy

Jamie_Carter wrote: »

No it isn't nonsense at all. It is a fact that these adaptors have caused fires,

So you'll not have any problems with providing a source for this, given it's a "fact"? Huge amounts of the folklore of electrical safety date back to the days of unfused 5 and 15A round-pin plugs, fused consumer units, no protective bonding, bakelite fittings and rubber insulated wiring. This is a prime example.

An unfused extension block is a mild fire risk because you can pull more than 13A without anything tripping. Each plug fuse would be within its rating, there's no fuse in an unfused block, and the breaker on the ring main is obviously rated to handle multiple 13A sockets, usually a minimum of 32A. UK plugs and sockets are massively over-specified (the contact areas are not far off those of, say, a 32A commando) but the internal wiring in an extension block may not be, and there may be appreciable resistance in the screw terminal blocks where the socket attaches to the ring main.

These days all sockets are installed to metal pattress boxes, and if the building's been rewired in the last thirty years the insulation is non-flammable, but it's a risk nonetheless.

But a fused block? It can't be used to connect more than 13A, because the fuse will blow. Your "weight pulling it out and causing arcing" story is on a par with "mobile phones igniting petrol vapour", and requires a similar suspension of physics. For a start off, to rotate the conductor pins requires the earth pin to physically cut through the socket --- dealing with the weight of the connector is one of the reasons why the earth pin is spaced so far above the live and neutral. And the contact surfaces of the line and neutral are the top and bottom, so even if the force manages to slightly reduce the contact pressure on the bottom, it'll increase it on the top (or vice versa). It would be interesting to use a test rig to see what the maximum current that a BS1363 plug/socket combination will take, but given that you can safely run 16A through the (minuscule by comparison) IEC 320 C19/20 connectors I would be amazed if the connector were not safe out to 30A or more, even with significant force on the plug.

Arcing within a modern (ie, not bakelite) connector isn't a significant fire risk: just what do you think it's going to ignite? If it's arcing over the connectors, it's all non-flammable, and if it's arcing to anything else (what?) then the RCD on the consumer unit will trip.

It's now illegal to sell adapters with more than two BS1363 sockets that are not fused. You can still get unfused doublers, and in principle you can therefore pull 26A out of a socket via one (using, perhaps, two 3KW electric fires, rather than as the OP wants to do, a bunch of computer equipment). I wouldn't do that myself, but the 3KW fires are a greater fire risk than the doubler.

I suspect that fire brigades don't have time to worry about fusing, and have rules that date back to BS546 round pin installations. And in general terms, adapters are poor practice, because they're not terribly reliable and tend to introduce trip hazards. But an adapter bought in the last twenty years, plugged into wiring installed in the last twenty years, via a modern consumer unit? Show us the fire.

bod1467

Jamie_Carter wrote: »

No it isn't

vaio wrote: »

oh yes it is

Is it panto season again?

Jamie_Carter

securityguy wrote: »

So you'll not have any problems with providing a source for this, given it's a "fact"? Huge amounts of the folklore of electrical safety date back to the days of unfused 5 and 15A round-pin plugs, fused consumer units, no protective bonding, bakelite fittings and rubber insulated wiring. This is a prime example.

An unfused extension block is a mild fire risk because you can pull more than 13A without anything tripping. Each plug fuse would be within its rating, there's no fuse in an unfused block, and the breaker on the ring main is obviously rated to handle multiple 13A sockets, usually a minimum of 32A. UK plugs and sockets are massively over-specified (the contact areas are not far off those of, say, a 32A commando) but the internal wiring in an extension block may not be, and there may be appreciable resistance in the screw terminal blocks where the socket attaches to the ring main.

These days all sockets are installed to metal pattress boxes, and if the building's been rewired in the last thirty years the insulation is non-flammable, but it's a risk nonetheless.

But a fused block? It can't be used to connect more than 13A, because the fuse will blow. Your "weight pulling it out and causing arcing" story is on a par with "mobile phones igniting petrol vapour", and requires a similar suspension of physics. For a start off, to rotate the conductor pins requires the earth pin to physically cut through the socket --- dealing with the weight of the connector is one of the reasons why the earth pin is spaced so far above the live and neutral. And the contact surfaces of the line and neutral are the top and bottom, so even if the force manages to slightly reduce the contact pressure on the bottom, it'll increase it on the top (or vice versa). It would be interesting to use a test rig to see what the maximum current that a BS1363 plug/socket combination will take, but given that you can safely run 16A through the (minuscule by comparison) IEC 320 C19/20 connectors I would be amazed if the connector were not safe out to 30A or more, even with significant force on the plug.

Arcing within a modern (ie, not bakelite) connector isn't a significant fire risk: just what do you think it's going to ignite? If it's arcing over the connectors, it's all non-flammable, and if it's arcing to anything else (what?) then the RCD on the consumer unit will trip.

It's now illegal to sell adapters with more than two BS1363 sockets that are not fused. You can still get unfused doublers, and in principle you can therefore pull 26A out of a socket via one (using, perhaps, two 3KW electric fires, rather than as the OP wants to do, a bunch of computer equipment). I wouldn't do that myself, but the 3KW fires are a greater fire risk than the doubler.

I suspect that fire brigades don't have time to worry about fusing, and have rules that date back to BS546 round pin installations. And in general terms, adapters are poor practice, because they're not terribly reliable and tend to introduce trip hazards. But an adapter bought in the last twenty years, plugged into wiring installed in the last twenty years, via a modern consumer unit? Show us the fire.

Your post just shows how little you know, and how little common sense you have.

It's the weight of plugs, and especially transformers that can pull adaptor blocks out of the wall socket. This can cause arcing and overheating. This has been known to cause fires both when the bakerlite breaks down due to heat, and in the transformer plugs that aren't bakerlite.

Not all houses have RCD's.

http://www.churchill.com/home-insurance/tips/electrical-overloading.htm

http://www.esc.org.uk/public/safety-in-the-home/product-safety/extensions-and-leads/

http://www.247electrics.co.uk/electrical-advice.html

http://www.plymouth.ac.uk/files/extranet/docs/ACC/129933.pdf

http://www.derbys-fire.gov.uk/news/news-items/is-your-childs-bedroom-safe-from-the-dangers-of-electrical-fires

I could add 100's of links.

If the ebay link is vaio's, then I should point out that it is against MSE rules to advertise on here.

Fifer

Jamie_Carter wrote: »

Your post just shows how little you know, and how little common sense you have.

It's the weight of plugs, and especially transformers that can pull adaptor blocks out of the wall socket. This can cause arcing and overheating. This has been known to cause fires both when the bakerlite breaks down due to heat, and in the transformer plugs that aren't bakerlite.

Not all houses have RCD's.

http://www.churchill.com/home-insurance/tips/electrical-overloading.htm

http://www.esc.org.uk/public/safety-in-the-home/product-safety/extensions-and-leads/

http://www.247electrics.co.uk/electrical-advice.html

http://www.plymouth.ac.uk/files/extranet/docs/ACC/129933.pdf

http://www.derbys-fire.gov.uk/news/news-items/is-your-childs-bedroom-safe-from-the-dangers-of-electrical-fires

I could add 100's of links.

If the ebay link is vaio's, then I should point out that it is against MSE rules to advertise on here.

I presume you mean bakelite? Bakelite hasn't been commonly used in household electric fittings for about half a century.

Naf

Fifer wrote: »

I presume you mean bakelite? Bakelite hasn't been commonly used in household electric fittings for about half a century.

Plus everything he's claiming isn't a danger inherent in the adapter; but a danger through misuse... I feel d!jà-vu coming on.

securityguy

Jamie_Carter wrote: »

This has been known to cause fires both when the bakerlite breaks down due to heat, and in the transformer plugs that aren't bakerlite.

I doubt a single bakelite (given your detailed knowledge of its flammability, it's surprising you can't actually spell it) multi-way adapter exists in use. BS1363 wiring didn't become common until the 1950s, and Bakelite was in sharp decline because of the labour intensive manufacturing process. Given it's very difficult, and expensive, to produce in solid blocks, I would be surprised if such devices were ever manufactured. If they were, then how many such devices are still be in use, fifty and more years later? We might as well worry about car safety based on the lack of seatbelts in an Austin Atlantic.

So putting archeology to one side, why not get yourself a copy of BS1363-3:1995, as I happen to have in front of me. Read it, with particular reference to section 23.2 and the requirement that adapters should neither burn nor become electrically unsafe when a glow-wire at 750C is applied.

I could add 100's of links.

None of which contain a documented case of a fire caused by an adapter somehow rotating in its socket and arcing, and all of which merely repeat the same myth you're promoting.

Jamie_Carter

Fifer wrote: »

I presume you mean bakelite? Bakelite hasn't been commonly used in household electric fittings for about half a century.

Who cares?
It's still a hard brittle plastic used for plugs.

Jamie_Carter

Naf wrote: »

Plus everything he's claiming isn't a danger inherent in the adapter; but a danger through misuse... I feel d!jà-vu coming on.

Not at all.
Do the adaptors come with instructions that tell you not to plug adaptor plugs into them?.....No they don't, so you can't claim misuse.

Is it misuse if it starts to pull out of the wall over time, due to the weight of the transformer plugs, combined with vibration, which can, and has in many cases caused arcing?

Yes if people only plugged normal plugs into them, and checked them on a regular basis, then they would be safe. But they don't. So it is far safer to use the bar adaptors, which is why they are recommended. Why can't you understand this simple concept? Or is it because you sell the block adaptors.

Jamie_Carter

securityguy wrote: »

I doubt a single bakelite (given your detailed knowledge of its flammability, it's surprising you can't actually spell it) multi-way adapter exists in use. BS1363 wiring didn't become common until the 1950s, and Bakelite was in sharp decline because of the labour intensive manufacturing process. Given it's very difficult, and expensive, to produce in solid blocks, I would be surprised if such devices were ever manufactured. If they were, then how many such devices are still be in use, fifty and more years later? We might as well worry about car safety based on the lack of seatbelts in an Austin Atlantic.

So putting archeology to one side, why not get yourself a copy of BS1363-3:1995, as I happen to have in front of me. Read it, with particular reference to section 23.2 and the requirement that adapters should neither burn nor become electrically unsafe when a glow-wire at 750C is applied.

I admit, I wasn't sure about the spelling, because I'm not an anorak on the subject. So I actually copied the spelling from your post (which you have now edited).:rotfl::rotfl::rotfl:

securityguy wrote: »

None of which contain a documented case of a fire caused by an adapter somehow rotating in its socket and arcing, and all of which merely repeat the same myth you're promoting.

A myth I'm promoting??:rotfl:

So you think people should believe a couple of people on a forum (at least one of which sells the block adaptors), over fire service and trading standards advice (as well as many other organisations)??
Even electrical contractors (who specialise in the subject) advise against the block adaptors.

I know who I would rather listen to

securityguy

Jamie_Carter wrote: »

Who cares?
It's still a hard brittle plastic used for plugs.

Plugs and adapters aren't made from brittle plastics. Those of us that have read the standard know this, because BS1363-3 includes hitting them with a hammer (20.1.4) and tumbling them in a metal drum (20.1.5). Brittle plastics don't survive either.