Sy cable question

[nathansinar]

Hi guys new to the forum and will introduce myself shortly

I have attached an image of a spur i have taken as you can see from the attached image

I am doing a trainee maintenance engineer role and just wanted some info on the below.

1.) when using sy cable do you have to earth the sheeth? i have had various reponses saying it is good practice but you can get away with using the cpc inside the cable and that alone?

2.) in the image i have posted becuase the sheeth hasnt been used an earth from the the spur to what ever it is feeding, does an earth need adding from the back of the spur plate to actual spur box as it could become live?? is it a reg that this needs to be done?

Thanks for help!

Nathan

 

[telectrix]

SY cable should not be used for that purpose. in the pic shown, what would happen if the strands of that metallic screen shorted out to a Live terminal in the accessory. at best it's a bodge. at worst dangerous.

 

[nathansinar]

Thanks for the reply it was something i did earlier this week i showed a sparky who said it isnt compulsory to earth the sheeth

I just wanted some proper feedback to the questions i rasied

Thanks
Nathan

 

[nathansinar]

Thanks

 

[westward10]

You will have difficulty finding a worded statement from an official source whether to earth the braid or not.

 

[nathansinar]

But as regards to the questions i asked is their any proper awnser? i was quite pleased with what i did

 

[telectrix]

IMO< the braid should be earthed, but i still frown on SY cable being used instead of SWA . also any of those black insulated conductors that carry line voltages should be sleeved brown and any neutrals sleeved blue.

 

[nathansinar]

Im only stating what a proper sparky said sy is adequte to use in this scenario?? and im just curious to see what the regs actually state to the 2 questions i posted

 

[Jamchiv01]

Are you allowed to use those glands to terminate SY? I was always taught to use these:

 

[drzsta]

I have seen plenty of instances where SY has been used such as you have shown but it does amuse me that if you are not going to use the appropriate glands and earth the braid, why bother using it at all?

 

[telectrix]

Are you allowed to use those glands to terminate SY? I was always taught to use these:

them's the correct glands for SY cable. braid is earthed and the cable is secured in the gland.

 

[Risteard]

Of course the correct SY glands should be used.

Strictly speaking BS7671 does not recognise the use of SY cable (or CY or YY) and it normally should only be used for controls. These cables are to VDE standards and there is no appropriate British Standard for them.

 

[telectrix]

and the braid is NOT A BLOODY SHEATH.

 

[nathansinar]

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

 

[Jamchiv01]

In answer to question 2:

The backbox doesn't need to be earthed as you have 2 fixed lugs that the faceplate screws into. However its always good practice to run an earth strapper from the FCU to the backbox.

Personally, I Connect the braid to earth but not to be used as an earth, as it can't handle the fault current
A internal conductor should be used for this.