After thinking about it a bit longer, I think that I'll still refer to them as insulated and sheathed cable as I do not see the double insulated mark on the cable any where (square inside a square). My logic is that the outer sheath/insulation is there not just for insulation value but also offers mechanical protection of the cable. As an electrician I feel that using the terminology of BS7671 is maybe the best way forward! After all these regulations are the bible to our trade!
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After thinking about it a bit longer, I think that I'll still refer to them as insulated and sheathed cable as I do not see the double insulated mark on the cable any where (square inside a square). My logic is that the outer sheath/insulation is there not just for insulation value but also offers mechanical protection of the cable. As an electrician I feel that using the terminology of BS7671 is maybe the best way forward! After all these regulations are the bible to our trade!
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H
holmslaw
You're getting things mixed up.
Double insulated means the cable core is completely surrounded by 2 layers of insulation, as with meter tails, this also means that they can only normally be single core cables.
The term double insulation no longer applies to electrical equipment. This is because the IET like to change the names of things to cause confusion and sell more books. The correct term is Class 2 this means they don't need to be earthed, class 1 equipment needs to be earthed.
Double insulated means the cable core is completely surrounded by 2 layers of insulation, as with meter tails, this also means that they can only normally be single core cables.
The term double insulation no longer applies to electrical equipment. This is because the IET like to change the names of things to cause confusion and sell more books. The correct term is Class 2 this means they don't need to be earthed, class 1 equipment needs to be earthed.
Not that I have "spat the dummy" its just that I find it hard to take criticism from some one who says;
And then;
Homslaw thanks for your response. I know about class 1 and class 2 equipment, what I am talking about is that grey sheath (insulation) is there to protect the coloured insulation from mechanical damage. If the cable was actually classed as double insulated it would be classed as class 2. Is it ,even though it is obviously not an enclosure or equipment?
Of course it wouldn't be, for the reason you explain yourself. Class I/II/III, as defined by the IET, relate only to 'Equipment', not cables. You can't just grab one set of definitions and apply them to something they are not intended to be applied to. Even insulated and sheathed singles which, as holmslaw said, are in engineering terms truly 'double insulated', do not count as 'equipment' to which the Class I/II/III classification could be applied.
Kind Regards, John
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I think I'll refer to the heading for table f4(i) in the onsite guide;
"Single core 70 degrees C thermoplastic (PVC) or thermosetting (note 1) insulated cables, non-armoured, with or without sheath (copper conductors)
As BS7671 is what I and other sparks refer to I will personally use the terminology used by the IET to save confusion. This is due to the fact the the sheath is not actually insulating the conductor, it is merely there to protect the actual internal insulation.
That's the bit that has been arousing my curiosity throughout this thread. Why did you need to ask in this ('DIY') forum about the 'proper' terminology to use, and why did I, a non-electrician, have to point out to you that 'insulated and sheathed' would be regarded by many as 'proper', since it was the terminology the IET always use in BS7671, OSG, GNs etc.? Anyone who has read BS7671 or the OSG must surely already be aware that there are countless references to 'insulated and sheathed' cables, but none to 'double insulated' cables. I'm just curious.
Kind Regards, John
The whole reason was to get a bit of debate going, which has happened. This is a DIY forum but when someone comes on with a DIY question the answers seem to be the same i.e non competent, get an electrician. It has been a good debate as people use different terminologies for the same thing. So I feel that this thread has been interesting and informative.
Hmmm, interesting answer - but, unless you have just been playing with people here by making up fictitious statements as you go along (which I don't think would go down very well at all with some in this forum!) why, for example, would someone familiar with BS7671 and who therefore knew the 'proper answer' write something like:
I remain curious!
Kind Regards, John.
He's changed his mind about that.
Only when they appear to be incompetent.
As I truly thought that I was using the wrong terminology. I actually had to look it up to find that the terminology was the same as BS7671.
I have also come to the conclusion that the IET terminology is for me the better option. I do though realize now that other people use different terminology for this cable as has been debated (on site it tends to just be tails).
Don't get upset because this "sad" and unimportant question has taken up so much of your time. My original post merely asked what other people call this type of cable.
I have also come to the conclusion that the IET terminology is for me the better option. I do though realize now that other people use different terminology for this cable as has been debated (on site it tends to just be tails).
Don't get upset because this "sad" and unimportant question has taken up so much of your time. My original post merely asked what other people call this type of cable.
I'm past the stage of having any confidnce that I know what you 'truly think'. As I've said/implied, from where I'm standing it looks as if you've either been playing with folk here or else you're a rather odd sort of electrician.
Kind Regards, John.
Maybe I have dragged this out a bit, but to be honest it was the earlier posts by yourself and others that dismissed my genuine question as pointless, trivial and irrelevant which got my back up. Maybe I have strung you on a bit but as said if you call some one "sad " for asking a question of any sort on a forum you deserve it.
Just for the record, I didn't say that you were sad, or that a person asking such a question was sad. What I did say was that it was sad to see someone saying that he found the question interesting, which is what I still think. However, from my viuewpoint, it has been quite interesting observing your behaviour.
Time for bed.
Kind Regards, John.
S
starspark
deleted see next post
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