Sy cable question

[andyb]

Whether it is an exposed conductive part is debatable.

Indeed it is. I do say in my first post on the subject 'If the braid is an exposed conductive part'
'

As a matter of interest how are you assessing the braids ability to carry fault current whilst suffering no thermal stress.

I'm not, I wouldn't know how to. I imagine there will be substantial thermal stress and damage with a fault to earth. There is on everything else.

What I'm saying is that if the braid is an exposed conductive part then a fault would need to disconnect the supply in .4 sec. assuming a TN supply.

 

[westward10]

There lays the problem which probably explains why this cable should not be used.
There should be no damage under fault conditions if conductors are correctly selected.

 

[andyb]

I don't use it either Westward, if you say that the braid is not an exposed conductive part and leave it, then someone puts a nail through the braid and live then it will always be live. Then if someone drops a socket as in the picture in the OP you can see the problem. Metal box, live braid, hold the box with one hand and touch the braid with the other it will hurt. Coupled with the fact that I assume there is no rcd protection to that circuit ( rcd socket) it could be very nasty. Also looking at the picture I assume that particular circuit is live as the rcd is holding in.

 

[sparksburnout]

Im just stating what a proper sparky has told me... the regs dont state that they have to be glanded like that? i agree earthing the sheeth is better but its not compulsory? and in the image shown does an earth need to be run from the back of spur plate to the actually box??

Thanks

Could I just ask a question? You have stated "this is something I did earlier this week" but you obviously don't really know what you are doing, why are you not looking in "the regs" or asking the person that is training you? Your post doesn't really seem to make much sense to me. Are you really a trainee? Or just "having a crack" at it? Just saying.....

 

[KennyKen]

The Cable is Concentric. If the proper SY glands are used between two metallic enclosure's. Then you wouldn't need to Earth the braid. Although I've never used this cable for sockets.

 

[Barry White]

Post 29 I got a bad electric shock from this type of cable the braid was live it was on a farm and the ground and me were wet .
If it had been earthed it may have tripped or it may have just burned off the fault who knows but at least I would not have had a shock.

 

[andyb]

The Cable is Concentric. If the proper SY glands are used between two metallic enclosure's. Then you wouldn't need to Earth the braid. Although I've never used this cable for sockets.

Assuming you mean earthed metallic enclosures then surely that would earth the braid Kenny. Or am I missing something?

 

[KennyKen]

Yeah too many opinions. I've used the cable for control/motor applications. That being said if it's being used to supply sockets then having a physical Earth from the braid is plausible. I think we can all agree that SY shouldn't be the chosen cable for said Install

 

[KennyKen]

Assuming you mean earthed metallic enclosures then surely that would earth the braid Kenny. Or am I missing something?

Of Course. The metallic enclosures would need to be earthed. I'm only basing my opinion on what I've used the cable for. I wouldn't use SY for Sockets. If I were then yeah I would probably create a physical Earth using the braid

 

[Darkwood]

I too have come across this cable in a poor condition hundreds of times but on 2 occasions the braid was live, this is over the last 5yrs so its worrying the impropoer use this cable is subject to, I'm on a site at the moment who have there own sparks and the sockets are in SY although they have maintained the braiding throughout by strapping it down at every end and point, I don't have issue with what they have done although I question the cable choice given its a factory environment, we have better methods for such installs.

 

[LeeH]

The amount of times I've seen it with no sheath left on it due to UV deterioration....leaving just the rusty braid there.

So let's leave it floating. Genious!

 

[Flanders]

From what i have come across on various sites it that it seams to be common pratice to use sy cable to supply equipment from bus bar tap off boxes , and use to make up extention leads in industrial environments , when i ask the question why tbey use this cable there answer is that its more robust than flex and Swa is far too heavey duty and its difficult if not impossible to terminate an swa into a camando plug (although i have seen some poor attempts ) ,i have been ask what i would suggest , to which i don't have an answer , so it there a more suitable cable to use? It would be interesting to send a fault current down some SY and see what happens , maybe JB from the Ytube will give it a go .
Looking at the ops install it neads
1 . the back box securing to the wall
2. the cables sleaved with the correct identification
3. if Sy cable is the only choice then gland it off with an sy gland

 

[Wilko]

Edit

 

[LeeH]

That's the stuff!

 

[DPG]

I've always thought it a very nice looking cable. If that counts for anything Daz

 

[LeeH]

@Flanders you can get a really tough flex but the name/code escapes me.

 

[Wilko]

Sorry about the almost random pic. I was part way through some rubbish and tried to delete it all, but the pic she stuck.

 

[darksideby182]

Refrigeration Engineer favourite this cable. As others have said its a poor cable.

 

[DPG]

See loads of aircon units wired up with it as well. Up to the external isolator in SWA and then out to the outdoor unit in SY. Daz

 

[darksideby182]

Yep seem to think it ideal and always it the wrong size of core normally 2.5mm when it should be 4mm/6mm