Not at the start of it?It will be on the end of the extension that I’m adding.
I suppose you know what you mean?I’m chopping off the 3 pin plug on the lights and adding a 1m ish extension with a 3 pin plug on the end.
Not at the start of it?It will be on the end of the extension that I’m adding.
I suppose you know what you mean?I’m chopping off the 3 pin plug on the lights and adding a 1m ish extension with a 3 pin plug on the end.
It very much does matter. The armouring is an exposed-conductive-part and must be Earthed. SWA must always be installed properly.Yes.
Well, it's not really suitable but as there is no requirement for armoured I suppose it doesn't really matter if it is not installed properly (for armoured) - just no point.
Or on the other hand, you can use anything you want; it's just cable and wires.
Not if none of it is exposed.It very much does matter. The armouring is an exposed-conductive-part and must be Earthed.
I don't see why if it is not actually being used for its SWA characteristics.SWA must always be installed properly.
For a start, as EFLI has implied, none of the armour would normally be 'exposed', in which case it could not be an 'eposed-c-p'. It's obviously true that it could become exposed (in places) if the outer sheth were mechanically damaged - but the same is true of anything within any cable that is mechanically damaged.It very much does matter. The armouring is an exposed-conductive-part and must be Earthed.
As I asked, if that is the case, then does the same apply to anything else metallic which might come into contact with the outer surface of an insulated-and-sheathed cable? ... and if not, why the inconsistency?You will find that cable armouring is always considered to be an exposed-conductive-part ...
I would think that depends upon what you mean by "present". If the cable is insulated and sheathed, there is nothing prohibiting its outer surface coming in contact with earthed items (whether it is carrying SELV, some other type of ELV or LV), so I don't see why it would not be acceptable for it to have an earthed covering (outside of the sheathing) as part of the structure of the cable. After all, I don't think anyone is suggesting that it is not permissible to put an SELV cable within earthed conduit, are they?just to add that with SELV no earth should be present
What? What does exposed mean?You will find that cable armouring is always considered to be an exposed-conductive-part, whether or not it is exposed to the touch.
Is it?Likewise metallic conduit/trunking is always considered to be an exposed-conductive-part. Indeed the IET Guidance Notes explicitly state this.
Yes, most of us ('regulars') probably understand all that, but it doesn't really alter what I said. If (as is the case) the outer surface of an insulated-and-sheathed cable carrying SELV is 'allowed' to come into contact with earth, or earthed items, then I don't see why it should cease to be 'allowed' if the 'earthed item (outside of the sheath of the cable) were part of the construction of the cable.John, by earth present,, i was meaning yes it`s ok and good for it to be close by and useable if needed in future. However not so close by and useable to be touchable whether deliberately or accidentally whilst touching a SELV wiring system , the S in SELV means separated and this must be preserved for safety. in other words a selv system is completely floating in respect to earth voltages at all times upon the whole system.
Again, I imagine that most of us agree with that. Other than in very localised environments, having an earth-referenced supply is an inevitable and unavoidable evil. If we attempted to have a floating supply network, I would expect that the incidental/accidental connections to earth would apply roughly similarly to both sides of the supply, in which case both sides ought to end up at potentials relative to earth of roughly half the 'between-sizes' supply potential.indeed the world could be a lot safer if all our mains voltages were completely floating in respect to earth (think bathroom shaver socket for example), however just one connection (resistive, capacitive or inducive) albeit accidentally means we have an earth which is the opposite polarity of any Live conductor except the N. In most situations we can not maintain an earth free system
Ok, (the regulators seem to considered that important).John, by earth present,, i was meaning yes it`s ok and good for it to be close by and useable if needed in future.
What am I missing?However not so close by and useable to be touchable whether deliberately or accidentally whilst touching a SELV wiring system
Right, so what did you mean by the above?, the S in SELV means separated and this must be preserved for safety. in other words a selv system is completely floating in respect to earth voltages at all times upon the whole system.
No argument with any of that, but I still don't see why that precludes having an earthed conductor within the physical cable (separated from the SELV conductors by two layers of insulating material), provided that earthed conductor is not in any way connected to either side of the SELV supply.OK. with SELV no part of the supply should have any reference to earth at all so that any power is one polarity or the other polarity and nothing else and all such voltages are extra low
If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Are you a trade or supplier? You can create your listing free at DIYnot Local