Use of sy cable

[polo1]

Peeps,
Your thoughts please on the use of sy cable in a domestic setting.
Came across an installation today where the supply to an immersion element had been run in sy cable. Overcurrent protection correct and circuit is covered by a 30mA rcd.

I think we are going to be doing an EICR in the property in the next few weeks and couldn’t decide how this might be coded.

What do you think?
TIA

 

[DT1991]

No code if installed correctly. IMO

 

[Zdb]

It does not comply with BS7671

 

[Zdb]

Has the braiding been correctly earthed on the SY cable in question?

 

[Dustydazzler]

SY for an immersion heater is a very odd choice of cable

 

[Strima]

C3 for me as not a suitable cable as this is not its intended use. Also as this is near s heat source the plastic coating will become brittle and crack over time.

 

[westward10]

Has the braiding been correctly earthed on the SY cable in question?

If you are going to earth it how can you be sure it is capable of carrying fault current if required.

 

[Zdb]

If you are going to earth it how can you be sure it is capable of carrying fault current if required.

IMO the braiding must be earthed but not used as an earth! I don't know its capability of carrying the fault current as not enough information has been provided.

 

[westward10]

IMO the braiding must be earthed but not used as an earth! I don't know its capability of carrying the fault current as not enough information has been provided.

Why are you earthing it. No it can't be used as a cpc but connecting it to earth leaves the possibility it could be subjected to fault current and if this is the case you must be satisfied it can carry the fault current.

 

[SparkySy]

I went to a farm with all the out buildings wired in SY not so long ago. Apparently done by a full NIC contractor. I didn't bother to argue with the farmer but it was rubbish none of the screens were earthed just cut off and taped up through stuffing glands.
What a waste of time and money when there are much better spec cables that can be used!

 

[StephenRowley]

Posted in error

 

[Dustydazzler]

I went to a farm with all the out buildings wired in SY not so long ago. Apparently done by a full NIC contractor. I didn't bother to argue with the farmer but it was rubbish none of the screens were earthed just cut off and taped up through stuffing glands.
What a waste of time and money when there are much better spec cables that can be used!

You would be amazed by the amount of ‘electricians’ who just cut off the braiding

 

[Zdb]

Why are you earthing it. No it can't be used as a cpc but connecting it to earth leaves the possibility it could be subjected to fault current and if this is the case you must be satisfied it can carry the fault current.

But on the other hand, not earthing it could cause it to become live if damaged?

 

[davesparks]

Why are you earthing it. No it can't be used as a cpc but connecting it to earth leaves the possibility it could be subjected to fault current and if this is the case you must be satisfied it can carry the fault current.

Not connecting it to earth will lead to capcitively coupled voltages appearing on the braid.

 

[westward10]

But on the other hand, not earthing it could cause it to become live if damaged?

In which case it would have to carry fault current.

 

[SparkySy]

Which takes you back to proving it can take fault current!

 

[Robson689]

You would be amazed by the amount of ‘electricians’ who just cut off the braiding

When we were taught terminating SY in college we were also always told the braid must be earthed but you must also have a dedicated CPC. The SY glands earth it anyway so don't see how it can be avoided unless plastic CU?

 

[SparkySy]

I've seen it used wrongly with plastic stuffing glands many times before just taped up! That would stop any continuity to earth.

 

[Tim Watkiss]

I really dislike sy cable for anything other than maybe industrial machine wiring, I come across it as a maintenance spark all the time and see mechanically biased engineers installing final circuits using it because "it's easier" but when you correctly earth the braiding it is not easier to install it's as easy to install armoured cable and you cut your fingers on the braiding and does not comply with the regs to boot. The braiding must be earthed or could potentially become live if the cable got bumped or damaged in some way. I would record as c3 if this is not the case, just a very odd cable for domestic use!

 

[Tim Watkiss]

When we were taught terminating SY in college we were also always told the braid must be earthed but you must also have a dedicated CPC. The SY glands earth it anyway so don't see how it can be avoided unless plastic CU?

People always just use a 20mm plastic gland to enter the db and don't earth the braiding I installed a circuit in a factory and there were 4 sy circuits all like this on that db and probably hundreds across the factory