The most basic problem with DIY work

[mfarrow]

And 13A fuses in a standard plugtop feeding a 0.75mm cable-lamp, or similar, isn't too clever either. My daughter recently bought a TV set with such an arrangement, provided by the manufacturer.
So the existing (approved) system is far from perfect, or even far from sound.

I'm not sure what the rules are for portable equipment, but if this were a fixed installation then reading the regs you might get away with not providing co-ordination between the protection device and the lead:

- You have a known load, so don't need protection against overload current (433.3.1 (ii)).
- You presumably have a two-core cable so are running a Class II installation circuit, and therefore can ignore all of 411.
- 434 does not specify requirements for co-ordination between conductor and device. Therefore the most onerous requirement for protection against fault current is 434.5.2, the formula for which would make 0.75mm² work for 0.4s but not 5s with a 13A fuse. Whether there is actually a specific time requirement under the portable equipment standards I don't know.

 

[JohnW2]

Just fitted a Hager board and they gave these settings: http://download.hager.com/hager.uk/files_download/user_instructions/torque-settings.pdf[/QUOTE]
Those are in the usual ballpark. ISTR that Wylex are a little lower with 1.7 Nm for MCBs and 2.0 Nm for RCDs and Main Switches - but, as I said, those torques feel rather low to me. What was your experience with the Hager ones - did you try tightening them to the recommended torques?

Kind Regards, John

 

[Astra99]

Picking up on Jackrae's comments about 0.75 cable being fitted with a 13A fuse, from what I have seen in the IT industry, it is common practise to install 5 or even 10A fuses in mains leads which terminate in the 2.5A-rated C6 "Cloverleaf" socket! I automatically replace them with 3A. As far as I am aware, 0.75 flex is rated at a max of 6A, so those manufacturers who insist on fitting 10A fuses need to be slapped down, and hard.

 

[SimonH2]

FWIW, while working in my mates 1980s bungalow, pretty well every connection I found to be loose - in quite a few cases, pulling a socket away from the wall left one or more wires behind.

But back to the very original question, I think part of the problem is that many of the terminal designs are - trying to stay polite - completely carp. A particular annoyance is the "square box and grubscrew" where there is room for a 2.5mm core to slip up along side the screw and not have a solid connection.

Much better are grubscrews which are sized so that there is no room for cores to slip up the side - but that means either very large screws or small terminals.

My preference is for rising box terminals, but they do have their own problems and aren't common AFAICS on normal accessories.

And lastly, I think life would be simpler if we still used a metric equivalent of the old 7/029

 

[JohnW2]

And lastly, I think life would be simpler if we still used a metric equivalent of the old 7/029

Indeed. I can but presume that cost was the main, if not only, reason for the appearance of solid conductors for the smallest cable sizes when things got metricated.

Kind Regards, John

 

[Jackrae]

Oh happy days 3/029, 7/029 etc. As to the screws, decent ones have the last thread missing and the end suitably domed so that they press into the wire rather than trying to cut it. But again the rising box is superior, though, as stated not ideal.

When did double wound silk go out of fashion !!!

For this interested the TV with the 13A fuse in its manufacturer supplied twin wire lead was a Samsung.

 

[ericmark]

Picking up on Jackrae's comments about 0.75 cable being fitted with a 13A fuse, from what I have seen in the IT industry, it is common practise to install 5 or even 10A fuses in mains leads which terminate in the 2.5A-rated C6 "Cloverleaf" socket! I automatically replace them with 3A. As far as I am aware, 0.75 flex is rated at a max of 6A, so those manufacturers who insist on fitting 10A fuses need to be slapped down, and hard.

The C15 kettle connector is also rated at 10A not 13A yet I would still fit a 13A and the C13 also rated 10A but in the main I would use 5A fuses.

We are suppose to test lead sets separate from the item they supply and as such we should not be looking at what they supply but the lead it's self and you are quite correct both the C5 and C7 are rated at 2.5A so should have 1A fuses fitted. However there has been a move to limit fuse sizes to either 3A or 13A so in the main a 3A would be used. But these are user replaceable parts and unless there is a sticker on the item saying use 3 Amp fuse then we have to expect the wrong size to be fitted.

I taught my children how to look at the rating plate and select the correct fuse. I had a selection 1, 3, 5, 7, 10, and 13 some times even had some 2A. However the problem arose when the school teacher tried to teach the subject in school only for my children to tell the school teacher "My dad says that's wrong you should not do that." it was not the only thing which caused problems my son was told there were two types of transistor did he know what the were to which he answered "Field effect and Bipolar sir" to which the teacher said no it's NPN and PNP to which may son burst out laughing.

I went to take "A" (believe that stands for advanced) level physics as if I did three subjects it was cheaper. They taught the kids how to wire a florescent lamp without including the ballast.

So the problem goes back to schools. Either teach it correct of don't teach it at all. But the national curriculum means teachers have to do as they are told and even when they know it's wrong they still have to teach the kids the wrong information. So the fault lies with the government and their selection of what should be taught.

I did a so called IT course and it's more to do with using word and cisco systems than how to wire plugs. OK taught how to fit a plug on a LAN cable but there was nothing taught about how to fit a plug. So there knowledge is from school who teach it wrong to start with.

 

[SimonH2]

However the problem arose when the school teacher tried to teach the subject in school only for my children to tell the school teacher ...

Yeah, I found my teachers didn't seem to appreciate being corrected either for some reason

 

[Jackrae]

Rather disrespectful (but maybe true) saying about the differences between engineers and teachers etc

Those who can - do

Those who can't - teach

Those who can't teach - inspect

 

[333rocky333]

As I have asked a number of times here (but have never got a response), does anyone still make sockets like this? (of which I have a few used specimens in my cellar):

Untitled

• JohnW2
• 29 Oct 2011
• 6

I last see one of them about 20 years ago, from CEF, RPP possibly like securespark says

The thing was rubbish i recall and the terminal block broke off or something, maybe I was too heavy handed as I was used to the old logic mk stuff

 

[flameport]

the problem arose when the school teacher tried to teach the subject in school only for my children to tell the school teacher "My dad says that's wrong you should not do that."

The only thing that changes with education between starting school for the first time and leaving many years later is that the lies which pass for information get smaller and less frequent.

 

[securespark]

As I have asked a number of times here (but have never got a response), does anyone still make sockets like this? (of which I have a few used specimens in my cellar):

Untitled

• JohnW2
• 29 Oct 2011
• 6

YES!!!!

I posted a picture of one above your post!

Apologies to 333...I really must read the whole thread before posting.

But I have seen new sockets like those, with harmonised colours.

 

[ericmark]

Had my son told the teacher he was wrong it may have not been so bad but to burst of laughing at him was the real insult.

That evening was teacher parent night and on seeing the science teacher it came up and the teacher was unaware about field effect transistors and said how they must be new. At which I explained they were invented first but perfected second and since patented in 1926.

The problem was my son had already passed his amateur radio exam at 14 years old so was quite into electronics this was some 16 years ago now he also has level 5 in electronics but still laughs at the teacher when reminded.

But to be fair teachers in my day only followed a syllabus in the last year before we took the new CSE which came out in my year before that there was a county certificate I got an FCE (Flintshire certificate of education) but only Grammar schools did "O" levels. So if the teacher did not know the subject he just didn't teach it.

Further education is no different my lecturers in IT admitted what they were teaching was not their field of expertise but they still had to teach it. The guy teaching physics was a chemist and his physics was taught to him 40 years ago in the same college.

Any wonder they get it wrong. Some were very good. They would re-research every year to keep updated but I am sure many like me took there 17th Edition exam as soon as they could and frankly the teachers had as much time as us to study so really was blind leading the blind.

 

[plugwash]

And 13A fuses in a standard plugtop feeding a 0.75mm cable-lamp, or similar, isn't too clever either.

You may or may not think it's "too clever" but IIRC BS1363 allows use of a 13A fuse with 0.75mm flex.

 

[JohnW2]

As I have asked a number of times here (but have never got a response), does anyone still make sockets like this? (of which I have a few used specimens in my cellar):<pic>

YES!!!! I posted a picture of one above your post! Apologies to 333...I really must read the whole thread before posting. But I have seen new sockets like those, with harmonised colours.

Ah - apologies - I also missed that previous post of yours (maybe posted whilst I was typing mine, since there were only a few minutes apart) - however, it was only a reference to the RPP ones from CEF, not a picture.

So, they still exist - so I presume that some people must use them.

Kind Regards, John