SY Cable? Thoughts?

Leroy Merlin · Nov 9, 2018

Morning all

I've recently been introduced to SY cable through work. I've had a look for more information on the web as I wanted to check ratings, uses etc. but I'm getting a lot of mixed information... many people say they use it but many others are saying that it doesn't comply with BS7671.

Apparently it is widely used on the continent for both control and power. I wondered if anyone could enlighten me on it's use in the UK.

I tried to search the forums for info but couldn't see relevant threads...

Thanks in advance

L

Spoon · Nov 9, 2018

We did use to use it until the manufacturers changed the spec.
It is now not suitable for fixed installations.

Risteard · Nov 9, 2018

It has no British Standard (it is a VDE cable) so isn't strictly compliant with BS7671 and therefore you are using it at your own risk.

SparkyChick · Nov 9, 2018

Spoon said:
We did use to use it until the manufacturers changed the spec.
It is now not suitable for fixed installations.

This subject has interested me. What did they change?

Ian1981 · Nov 9, 2018

I can’t speak for all manufacturers but Elandcables website says that it is not suitable for fixed wiring for compliance with bs7671.
Take a look at their site.

The Ghost · Nov 9, 2018

OSG also states it may not comply.

Spoon · Nov 9, 2018

SparkyChick said:
This subject has interested me. What did they change?

They put a comment in that it was not suitable for fixed installations, but I cant find it now.... Strange.

Olflex state

I'll keep searching

JAWS · Nov 9, 2018

We were using SY cable at college the other day.

Just found this which is quite interesting Should SY, YY and CY cables be used in electrical installations? - https://www.voltimum.co.uk/articles/should-sy-yy-and-cy-cables-be-used

Spoon · Nov 9, 2018

As @Ian1981 has pointed out:
Eland say:

Spoon · Nov 9, 2018

Belden state:

[ElectriciansForums.net] SY Cable? Thoughts?

The below is pinched from @Massive1 post above:

'VDE 0250'
The VDE Institute is a national and internationally accredited institution in the field of testing and certification of electrotechnical devices, components and systems. (VDE stands for Verband der Elektrotechnik, Elektronik und Informationstechnik)

VDE publish a series of standards covering, among other things, various cable types. However, simply quoting the term, 'VDE 0250' is meaningless because it is not a specification and the ‘0250’ is just one part of a complete standard number. In order to be meaningful, the full standard number must be quoted. For example, the German NYM type of cable is defined in VDE 0250-204:2000.

The full VDE standard to which these cables might conform is unclear.

VDE standards are German national standards. They are neither Harmonised European (EN) nor International (IEC) standards. Therefore their use under BS 7671 is not automatic and they would be subject to the required engineering assessment regarding safety, etc.

NAPIT understands that the VDE Institute has issued certification to a small number of cable manufacturers for some SY, CY, and YY cables and that this certification is based on individual cable manufacturer specifications which are confidential to both VDE and the manufacturer. As these specifications have not been published, we are unable to determine which material and construction specifications or tests have been applied. Consequently, authoritive literature is not available to assist in making engineering judgements.

Spoon · Nov 9, 2018

Leroy Merlin said:
Morning all

I've recently been introduced to SY cable through work. I've had a look for more information on the web as I wanted to check ratings, uses etc. but I'm getting a lot of mixed information... many people say they use it but many others are saying that it doesn't comply with BS7671.

Apparently it is widely used on the continent for both control and power. I wondered if anyone could enlighten me on it's use in the UK.

I tried to search the forums for info but couldn't see relevant threads...

Thanks in advance

L

Out of interest mate. Why use SY cable? Why not use NYY-J cable?
NYY-J cable is cheaper and you don't need a special gland, so the gland is cheaper as well.

David Prosser · Nov 9, 2018

I thought you can get SY cable that complies with BS EN 50525-2-51 making it suitable for use in control and automation, depends on what the OP was using it for in work. We use it regularly for V.S.D. to motor connections and for connecting instrumentation.

Leroy Merlin · Nov 9, 2018

Spoon said:
Out of interest mate. Why use SY cable? Why not use NYY-J cable?
NYY-J cable is cheaper and you don't need a special gland, so the gland is cheaper as well.

Cheers, I think the powers that be want the extra mechanical protection though...

Spoon · Nov 9, 2018

Leroy Merlin said:
Cheers, I think the powers that be want the extra mechanical protection though...

Can you please clarify what the cable will be used for.
Is it for the mains power for machinery or V.S.D. to motor connections....

Leroy Merlin · Nov 9, 2018

Spoon said:
Can you please clarify what the cable will be used for.
Is it for the mains power for machinery or V.S.D. to motor connections....

They are using it to supply power to a water heater, five core SY L1, L2, L3, N and PE but they want it screened as well. I believe that they need to control the water temp quite accurately so I assume this is why they require the screen.

Deuce · Nov 9, 2018

This has come up before.. What is the right thing to do? On some machines you can't rely upon RCD protection so you kind of need a cable with mechanical protection built in, and earth sheathed in case it is damaged/crushed.

Always feels to me like an unfair choice, to either downgrade real-world safety in order meet the regs, or follow common sense and risk criticism for it.

Darkwood · Nov 9, 2018

SY and machinery, depends on the environmental influences, SY usually requires other IP and mechanical protections around machinery as it is not suitable to the oils, coolants etc commonly used, also it shouldn't really be bought as a mechanically enhanced protected cable, this is a screening and originally design for screening purposes, it should have additional mechanical protection if used in areas where it may be subject to damage etc.

westward10 · Nov 9, 2018

This biggest problem if you decide to use the braid which you shouldn't, as part of a means for ADS is assessing the braids capability of carrying fault current.

Deuce · Nov 9, 2018

darkwood said:
SY and machinery, depends on the environmental influences, SY usually requires other IP and mechanical protections around machinery as it is not suitable to the oils, coolants etc commonly used, also it shouldn't really be bought as a mechanically enhanced protected cable, this is a screening and originally design for screening purposes, it should have additional mechanical protection if used in areas where it may be subject to damage etc.

westward10 said:
This biggest problem if you decide to use the braid which you shouldn't, as part of a means for ADS is assessing the braids capability of carrying fault current.

Fair points.

The thing is, the braid is a useful last defence if the cable is damaged (unnoticed) and then someone touches it. In general, it's also pretty tough stuff. Designed for screening, but designed to be extra tough too.

Even 'fixed' machines get moved away from walls for servicing etc. Damage can occur at anytime and for me, SY feels like a good choice. I accept the braid can't be relied on solely, but one day it might be in the right place to save a nasty incident. Just feels right to earth the surface of exposed cable if it's possible to do so.

Darkwood · Nov 9, 2018

A few points to note:-

SY cable does not comply to British Standards in using it you will have:-
A- understand why it does not comply.
B- document its use and why you believe it is suitable for your installation.

The use of this cable in the industry brought it big concerns and was clearly been used for purposes it was never designed for or was suitable for.
If you have it on or around machinery where it may come into contact with the normal oils, greases, coolants etc used then it should not be used.
If it is subject to possible damage then it should not be chosen in the mindset that it is a armoured flex, it is not it is a screened flex which can afford some kinds of damage a standard flex couldn't but also it is prone to damage where other flexes would be resistant IE UV damage, outer sheath is softer than standard pvc environmental covering and it has low resistance to chemicals and oils.

I conclude this cable should not even be in our industry, it is mi-sold, misused and has forced the regulatory bodies to step it and express its use does not conform to our recognised standards.

I have a pet hate of this cable because of the amount of times I have seen the result of its poor application, I have in 2 decades found several times that damaged cable has made the sheath live and in some cases given uses shocks simply because of misuse and the wrong applications of its use.

I would say if you have routine machine movement for maintenance and cleaning then wire it with a suitable HO7RN-F a cable designed for the purpose of most industrial environments and put it on a plug and socket arrangement so it can be disconnected, I have done this for many decades and never had issues, if you find you are then the operators/employees need educating and taught how to clean and service the machines safely.

Leroy Merlin · Nov 9, 2018

darkwood said:
A few points to note:-

SY cable does not comply to British Standards in using it you will have:-
A- understand why it does not comply.
B- document its use and why you believe it is suitable for your installation.

The use of this cable in the industry brought it big concerns and was clearly been used for purposes it was never designed for or was suitable for.
If you have it on or around machinery where it may come into contact with the normal oils, greases, coolants etc used then it should not be used.
If it is subject to possible damage then it should not be chosen in the mindset that it is a armoured flex, it is not it is a screened flex which can afford some kinds of damage a standard flex couldn't but also it is prone to damage where other flexes would be resistant IE UV damage, outer sheath is softer than standard pvc environmental covering and it has low resistance to chemicals and oils.

I conclude this cable should not even be in our industry, it is mi-sold, misused and has forced the regulatory bodies to step it and express its use does not conform to our recognised standards.

I have a pet hate of this cable because of the amount of times I have seen the result of its poor application, I have in 2 decades found several times that damaged cable has made the sheath live and in some cases given uses shocks simply because of misuse and the wrong applications of its use.

I would say if you have routine machine movement for maintenance and cleaning then wire it with a suitable HO7RN-F a cable designed for the purpose of most industrial environments and put it on a plug and socket arrangement so it can be disconnected, I have done this for many decades and never had issues, if you find you are then the operators/employees need educating and taught how to clean and service the machines safely.

Thanks for the replies, I'll pass this upstairs... Just spoke with RS and asked if they could confirm if it was OK to use in the UK and if they have any BS7671 compliant SY, as you would expect, they said not...

Darkwood · Nov 9, 2018

Here is an informative read up ...

Should SY, YY and CY cables be used in electrical installations? - https://www.voltimum.co.uk/articles/should-sy-yy-and-cy-cables-be-used

PS - I will admit I use it myself but only when I know that it is suitable and not subject to any environmental concerns, I use CY for motor VSD control and sometimes the motor supply as it affords a suitable screening.

Spoon · Nov 9, 2018

Leroy Merlin said:
Thanks for the replies, I'll pass this upstairs... Just spoke with RS and asked if they could confirm if it was OK to use in the UK and if they have any BS7671 compliant SY, as you would expect, they said not...

I remember when I noticed the manufacturers has put the 'not suitable for fixed installations' note on their SY cables, RS cables had not added this note for their SY cables. I contacted them, showing them the other cable manufacturers notes and asked if their cable was suitable for fixed installations. They said they they would changed the description of theirs to suit the other manufacturers.