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why is the contraction of a layout power supply thread locked


Junctionmad

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If you mean the construction thread then I suspect this final comment by Brian explains why.

 

 

 

.... As an electrical engineer and also now a PAT tester and qualified to the IEE 17th edition, I find some comments made on open forums somewhat bizarre, possibly risky and at times misleading to those who are reading them and who are probably not electrically minded.

 

To be honest and IMO, all this discussion around mains fusing ratings, mains cables etc shouldn't be discussed here.  If anyone isn't sure then the only advice should be... Get a qualified electrician or electrical engineer to undertake the work for you.   Safety of both the individual and the property has to be paramount! ....

 

Fantastically good advice. I too trained as an electrical engineer and over the years I've seen some horror stories perpetrated by those who don't recognise where their capabilities run out of steam. In such circumstances it does nobody any favours to offer help at a distance where it's impossible to physically check the finished piece of work before it's used.

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Fantastically good advice. I too trained as an electrical engineer and over the years I've seen some horror stories perpetrated by those who don't recognise where their capabilities run out of steam. In such circumstances it does nobody any favours to offer help at a distance where it's impossible to physically check the finished piece of work before it's used.

perhaps, but the subject matter is no more complex then wring a standard lamp and selecting a fuse.  if there is lack of knowledge then surely a thread like that is useful 

 

theres nothing really worse then " experts" wagging fingers without  explaining themselves , and I know, Im a 30 year trained EE

 

otherwise this is like sex education for teenagers, "dont do it" say the "experts" , and thousands ignore the advice etc 

 

Im mean the OP was asking about fuses, what complex about giving such advice.  

sure the RCD will save them anyway :D

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A) not all installation have RCDs as an EE you should be aware of that.

B ) teaching someone via a forum instead of standing next to them is very risky as comments can be interpurted differently or simply just misunderstood.

C) Mains power can kill, cause serious burn injury or fires if not correctly installed and protected. Are you prepared to accept that risk? I doubt it

D) people on this very forum have openly stated they have built mains fed power supplies in wooden boxes which they belive are ideal for purpose. As an EE you will fully understand that In itself is an issue and is totally incorrect.

E) no one is wagging a finger. Simply pointing out that these topics are a dangerous source of miss information or correct information that can be easily misinterpreted.

 

I seriously hope that the sort of comment posted above is not a generalisation of the way mains power is to be flippantly treated!

There is no real reason to continue this now!

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A) not all installation have RCDs as an EE you should be aware of that.

err hence my emoticon 

 

 

B ) teaching someone via a forum instead of standing next to them is very risky as comments can be interpurted differently or simply just misunderstood.

well  lets start burning all those textbooks in libraries then, we certainly dont want the ill-informed to read them 

 

 

C) Mains power can kill, cause serious burn injury or fires if not correctly installed and protected. Are you prepared to accept that risk? I doubt it

many many things can kill, should i not suggest using a lawn mower too,,,,,,

 

 

D) people on this very forum have openly stated they have built mains fed power supplies in wooden boxes which they belive are ideal for purpose. As an EE you will fully understand that In itself is an issue and is totally incorrect.

Nothing wrong with a good quality  wooden box, PYE radios cant be completely wrong .  just what are you objecting too, please elaborate as tho your specific concerns 

 

 

E) no one is wagging a finger. Simply pointing out that these topics are a dangerous source of miss information or correct information that can be easily misinterpreted.

Its fine to say " what you are doing is wrong " and then going on to actually lay out why you think so 

 

its nonsense to just go around saying "ooooh mains is dangerous "  and I know , Im an expert , that simply doesnt add anything to the OP knowledge

 

I seriously hope that the sort of comment posted above is not a generalisation of the way mains power is to be flippantly treated!

I made a little  joke or is mains power up there with animal rights and PC

 

 

There is no real reason to continue this now!

I see no reason why the OPs question resulted in the thread being locked, seemingly as a result of " bogeyman" warnings. The OP is my view is entitled to receive a fair  hearing, educated advice  and or debate . It is not for me or you .  to determine whats safe thats up to the OP .

 

I mean , The OP asks , : whats the safest way to climb down a cliff", "jump off i say "  , " you shouldn't be giving him bad advice, I know better, " says the expert and the thread gets locked

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The OP question was answered!

A wooden enclosure will fail a PAT examination as its not a suitable material as it can get damp very easily.

The Boogeyman is you, you're comment just don't cut it on reasons of safety.

The problem wth little jokes Is they can get taken to be correct, see what I meant about misunderstandings!

If anyone learnt all from text books or reading and have no hands on experience or was never shown how to do it correctly by someone else teaching then they are anexception. Books and much on the Internet give invaluable advice and many facts. I never said they didn't. But how the audience who reads that information treats it is the dangerous part. Hence virtually all items will have a printed disclaimer which forums AFAIK don't have!

 

The topic your referencing was locked as I suspect the forum wants to ensure only correct information is available. It may become unlocked later on? I have no knowledge of that. I think this topic has got totally out of hand and perhaps explains why it was in some ways ithe other was locked?

 

I now won't post again on this unless I'm belittled as clearly there are too many people saying to many things.

 

Just remember Safety First.

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But you've answered my question. At least you have a reason

 

Given the op has already said he is or has built it , the issue of pat testing hardly applies. I don't think from memory it applies to experimental construction either . If he was proposing a commercial product etc, the advice would be different.

 

Why would a wooden box used in a model railway get wet ?

 

I'm not belittling anyone , merely that simply because the topic involves " mains " is not in itself a reason to lock a thread.

 

Any way I've made my view known and the hidden levers of rmweb can listen or not

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I too was annoyed when the thread was locked.  

Brian left a number of issues unanswered.

Crossland made a valid point about fuses for leads. I am sure few people even consider that where more than one "Appliance" is connected through a single lead then each "Appliance" should have its own fuse. Normally an extension lead will have its own fuse and the "Appliances" have an appropriate fuse in their own plugs .   

In a model railway power supply only too often the individual power supplies, transformers etc are hard wired to a single input lead without individual fuses.

If constructing a power supply "Box" it is beat to either use a fused plug with the correct fuse for each transformer,  or a separate fuse of the correct rating for each transformer, a square white standard domestic fuse holder is ideal.

Most non model railway transformers, car battery chargers etc seem to have a fuse on the mains input as standard.

It has to be common sense to fit an RCD to any metal cased power supply to be used in a multiplicity of venues. The reference to Ring mains is irrelevant. Until recently our 1976 built Village Hall did not have RCD's on the sockets, merely earth leakage protection. Again the 1990s built extension to our Village Hall has radial not ring circuits, and the whole hall is wired with split phase 240 volt as are many 3 phase served premises or similar vintage inevitably including many exhibition venues.    

Personally I would consider using a computer cooling fan in any bespoke power supply as components can get hot during 6 or so hours continuous operation at an exhibition.

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If you mean the construction thread then I suspect this final comment by Brian explains why.

 

 

.... As an electrical engineer and also now a PAT tester and qualified to the IEE 17th edition, I find some comments made on open forums somewhat bizarre, possibly risky and at times misleading to those who are reading them and who are probably not electrically minded.

 

To be honest and IMO, all this discussion around mains fusing ratings, mains cables etc shouldn't be discussed here.  If anyone isn't sure then the only advice should be... Get a qualified electrician or electrical engineer to undertake the work for you.   Safety of both the individual and the property has to be paramount! ....

 

 

Fantastically good advice. I too trained as an electrical engineer and over the years I've seen some horror stories perpetrated by those who don't recognise where their capabilities run out of steam. In such circumstances it does nobody any favours to offer help at a distance where it's impossible to physically check the finished piece of work before it's used.

 

Agreed. But in that case how does locking misinformation in place help? It actually makes matters worse in that it can't be corrected or challenged.

 

The locking of topics continues to be one of the mysteries of RMweb, when the proper response is that such content should be deleted. At present whatever is in that topic is being indexed on Google, stored forever on the Wayback Machine, and is available to be read by everyone on the planet.

 

Martin.

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Can I just point out that wooden boxes for mains electrical equipment is something that happens on a vast scale. Every guitar amplifier, PA etc,  I have ever come across is just that. They may be covered in Rexine and look pretty, but they are just wooden boxes, with sometimes very large transformers and amplifiers all happily screwed in them. They survive being chucked in the back of Transits by roadies, and I've even seen a pint of beer poured into the heat grills on one, and it still worked.

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Can I just point out that wooden boxes for mains electrical equipment is something that happens on a vast scale. Every guitar amplifier, PA etc,  I have ever come across is just that. They may be covered in Rexine and look pretty, but they are just wooden boxes, with sometimes very large transformers and amplifiers all happily screwed in them. They survive being chucked in the back of Transits by roadies, and I've even seen a pint of beer poured into the heat grills on one, and it still worked.

 

Aye, and I've seen some spectacular shocks from touching the microphone whilst touching the guitar strings when one amplifier or the other isn't earthed. I always checked earths on all sockets to be used by the bands before setting anything up.

 

I had some clown pour/spill a pint of Old Speckled Hen into my PA amp. The bang as the magic smoke escaped was impressive. He got two shocks - my fist in his face, followed by the bill for it's replacement.

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Can I just point out that wooden boxes for mains electrical equipment is something that happens on a vast scale. Every guitar amplifier, PA etc,  I have ever come across is just that. They may be covered in Rexine and look pretty, but they are just wooden boxes, with sometimes very large transformers and amplifiers all happily screwed in them. They survive being chucked in the back of Transits by roadies, and I've even seen a pint of beer poured into the heat grills on one, and it still worked.Where 

Where did wooden box come from, the original post said steel.  Wood has the important attribute that it does not conduct very well at least not when it is dry,  Amplifiers are probably a bit off topic but you can get some very funny results from plugging one part of a PA system into one phase of a supply and the other part into another phase.  

Two different DCC power units plugged into different phases feeding the same layout could be interesting / frustrating / expensive. (As could two adjacent layouts on R/C)

Back to the original post, and I'm out on a limb here but I submit that the outputs should have 1 amp overload protection. Point tags and some current collectors, and many loco to tender connections wont take more than 1 amp.  Stop a  loco with loco and tender tender picks over an insulated rail joint with one side shorted out as in approaching a wrongly set live frog point and up to 4 amps goes through some very small wires, tiny point tags and a tiny plug.

I suggest for DCC the Bus bar needs sectioning for each circuit and sectionalising so no more than 1 train is fed by each circuit breaker and 1 amp breakers fitted.   The old 1950's Triang control (The little 6" square box not the transformer) is ideal as the button needs to be reset.   Most DC power supplies have a 1 amp breaker fitted to the output as standard it is just the DCC which does not.

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Two different DCC power units plugged into different phases feeding the same layout could be interesting / frustrating / expensive.

That depends on how/if the power supplies are isolated.

 

Point tags and some current collectors, and many loco to tender connections wont take more than 1 amp.

That's why DCC users who understand the best practice will not rely on the switch blades to route the power through a turnout.

 

They will sustain way more than 1 Amp for a limited time. That's why DCC boosters have fast accurate overload detection and cutout. Only poor installation will result in sustained overload currents capable of doing any damage.

 

I suggest for DCC the Bus bar needs sectioning for each circuit and sectionalising so no more than 1 train is fed by each circuit breaker

That will not do any harm but will be expensive and totally unneccessary.

 

and 1 amp breakers fitted.   The old 1950's Triang control (The little 6" square box not the transformer) is ideal as the button needs to be reset.

Is it designed for AC? Does it affect the DCC signal? What's the real trip current and the variation between units (and don't say 1 Amp)? Even more ideal are the widely available (from multiple suppliers) fast and accurate modules designed specifically to do the job.

 

Most DC power supplies have a 1 amp breaker fitted to the output as standard it is just the DCC which does not.

 

That's to protect the transformer and the rectifiers which are probably only rated at 1 Amp. There's no reason a DC controller needs to be limited to 1 Amp, other than it would be a waste for most situations.

 

Please don't simply try to "read across" from your DC experience to DCC.

 

Andrew

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The OP asked why was it locked. Only Andy or the Mod who locked the thread can really answer that. So far there has been no comment on this thread from Admin.

 

I think we can all guess why.

Trouble is, it can only be a matter of time before discussions about untrained individuals using sharp objects to make things for themselves are banned for the same reason.

Oh dear - there go the 'Kitbuilding/Scratchbulding/Moditying' sections....

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Agreed. But in that case how does locking misinformation in place help? It actually makes matters worse in that it can't be corrected or challenged.

 

The locking of topics continues to be one of the mysteries of RMweb, when the proper response is that such content should be deleted. At present whatever is in that topic is being indexed on Google, stored forever on the Wayback Machine, and is available to be read by everyone on the planet.

 

Martin.

I offer no views, let alone wisdom, on the locking policies of RMweb, although I suspect the % of members who would use the Wayback Machine is in low single figures. At 67 I have yet to join them.

 

However, your remark about the planet is spot on. There are plenty of us who do not reside in the UK, so IEE17 matters not a lot, however effective it is for practitioners. And plenty of us have plugs that cannot take a fuse. And we live in countries that haven't heard of a ring-main, either. So mains theory that avoids those terms may be the one that should best be expounded.

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I think we can all guess why.

Trouble is, it can only be a matter of time before discussions about untrained individuals using sharp objects to make things for themselves are banned for the same reason.

Oh dear - there go the 'Kitbuilding/Scratchbulding/Moditying' sections....

 

Generally it's considered ok to inflict damage on yourself in the cause.

 

But killing other people is frowned on. Mains electricity dangerous.

 

Martin.

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II suspect the % of members who would use the Wayback Machine is in low single figures. At 67 I have yet to join them.

 

The Wayback Machine isn't for use now, although it is sometimes useful.

 

It's for use in 50 yeas time: http://archive.org/web/

 

But here is the first page of RMweb from 10 years ago: http://web.archive.org/web/20050405174230/http://www.rmweb.co.uk/

 

Martin.

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Hmmm, so my 8 amp dcc unit for G scale must give some nightmares? The ones sold for the toy market are limited to 5 amp but there's no limit on modellers ones. In the U.S. I know of layouts using up to 20 amps but with proper wiring and not relying on fishplates or point blades.

Discussion and reading all sources means it can be safe, anyone who only reads part of the thread or just one source that contains contradictions is unsafe not the info.

My garden railway and exhibition controllers are housed in tough plastic boxes to protect from the rain and drink spills and I'd be more concerned about the standard of wiring running through wood and polystyrene layouts in some cases than a properly ventilated wood control box.

Forums are a perfectly safe place to discuss mains electricity and the sensible ones then know when they should ask for help and possibly find someone to help who might be able to suggest a commercial product many times cheaper than paying an electrician to wire up their custom build.

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The Wayback Machine isn't for use now, although it is sometimes useful.

 

It's for use in 50 yeas time: http://archive.org/web/

 

But here is the first page of RMweb from 10 years ago: http://web.archive.org/web/20050405174230/http://www.rmweb.co.uk/

 

Martin.

 

Hi Martin, I have used the Wayback Machine, but generally find you cannot drill down any further than the main topic, so have been unable to get to individual posts.  

 

Have you found another way in as I agree, it would be useful to go back to actual posts?

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The logical conclusion here is that, eventually, all online discussion must be reduced to a level and range of subjects that are considered safe for a rather dim 5 year old.

 

Now, if you'll excuse me, I'm off to peruse my construction drawings for a Sten gun, whilst waiting for my bio-diesel to brew from methanol and caustic soda and keeping an eye on the progress of that concentrated hydrochloric acid I'm using to get iron stains off some earthenware tiles. Then I'll have a fry up with some nice wild mushrooms and round the evening off by sticking together some bits of wooden ultralight aeroplane, all using information found either in books or on the internet. Given that I have no formal training or qualifications related to firearms, chemical engineering, botany (or whatever fungi fall under these days) or aircraft maintenance at least one of these activities will probably kill me.  Given, however, that I'm also not sufficiently stupid to actually build one, get any of the chemicals mentioned on or into me, eat anything I haven't made absolutely certain of through multiple corroborating sources or fail to follow some fairly straightforward inspection and testing requirements (also available on the internet fro reputable sources) respectively, maybe they won't.

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I remember in the late '50's getting a book from the school library, "The Boys Book Of Electricity", In it were instructions for make a shocking coil, a Wimshurst machine, an X-ray machine, (you could buy an X-ray tube from the radio surplus shop for £7.00), how to make your own X-ray plates and what chemicals were required, and a valve radio amongst other projects.

Was electricity more safer then or were boys more capable than now?

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