SY Cable? Thoughts?

[Leroy Merlin]

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]

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

 

[Risteard]

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]

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]

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]

OSG also states it may not comply.

 

[Spoon]

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]

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]

As @Ian1981 has pointed out:
Eland say:

 

[Spoon]

Belden state:


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]

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]

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]

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]

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]

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]

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]

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]

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]

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.

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]

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]

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]

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]

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.

 

[suffolkspark]

 

[Spoon]

View attachment 45609

There you go mate. Nice screen shot of it.

 

[suffolkspark]

Cheers i took mine on my phone last night as was having this very chat with another spark who was wiring up a joule cylinder and heat pumps and the manufacturers instructions sugested using SY!!!

 

[Deuce]

Guess that's this debate ended then.

Got to say though, I see the h07 get damaged all the time too. Mostly deep nicks in the outer sheath. In fairness, in my industry 20m lengths of it are dragged around and left laid on the floor/gravel/grass whatever - and then walked over for a couple of weeks before getting dragged back into a flight case

 

[Spoon]

Cheers i took mine on my phone last night as was having this very chat with another spark who was wiring up a joule cylinder and heat pumps and the manufacturers instructions sugested using SY!!!

I can cheat. We got the 18th and OSG for work. I took them to bits and PDF/OCR them. Makes it so you search them easily.

 

[Midwest]

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.

Didn’t Massive 1 already post that link?

 

[Darkwood]

Guess that's this debate ended then.

Got to say though, I see the h07 get damaged all the time too. Mostly deep nicks in the outer sheath. In fairness, in my industry 20m lengths of it are dragged around and left laid on the floor/gravel/grass whatever - and then walked over for a couple of weeks before getting dragged back into a flight case

I suggest it is not that the cables are a poor choice but the fact you are running them along the ground in a harsh environment, you need to look into other suitable means like cable protection channelling like they use on road works etc, we have this set up in the factories I work in, also voltages used should be considered IE 110v gear.

I understand that sometimes they cables will be subject to some wear and tear but if this is the case then more routine checks and replacement may be the only real answer but I struggle to see that there isn't any other solutions, we have in the past dug the floors up and put cable raceways in to allow power points at better suited positions minimising extension runs.

 

[Midwest]

I recall in another piece on this subject, that if a designer was to use such a cable in a BS7671 installation, then it would have to be noted as a departure from BS7671 and reg 120.3 would have to apply.

 

[davesparks]

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

But SY has no extra mechanical protection. Heavy duty flex such as H07RNF is more mechanically strong and probably better suited to the job.

 

[Tes369]

And the cost ?

 

[Spoon]

And the cost ?

See post #11 mate

 

[Deuce]

I suggest it is not that the cables are a poor choice but the fact you are running them along the ground in a harsh environment, you need to look into other suitable means like cable protection channelling like they use on road works etc, we have this set up in the factories I work in, also voltages used should be considered IE 110v gear.

I understand that sometimes they cables will be subject to some wear and tear but if this is the case then more routine checks and replacement may be the only real answer but I struggle to see that there isn't any other solutions, we have in the past dug the floors up and put cable raceways in to allow power points at better suited positions minimising extension runs.

No chance, its the way it is backstage everywhere. And on location in TV, cables everywhere. Sometimes it's not so bad in the studio on longer running series but for one day get in, one day get out, it's chaotic. Safety stats however remain very high - make of that what you will.

Each cable/distro is checked/tested as it's laid out and connected at least.

 

[davesparks]

No chance, its the way it is backstage everywhere. And on location in TV, cables everywhere. Sometimes it's not so bad in the studio on longer running series but for one day get in, one day get out, it's chaotic. Safety stats however remain very high - make of that what you will.

Each cable/distro is checked/tested as it's laid out and connected at least.

Thats not the way it is backstage everywhere, all of the backstage environments I've worked in we've always run cables where they don't get walked all over or give them additional protection.

 

[Deuce]

Thats not the way it is backstage everywhere, all of the backstage environments I've worked in we've always run cables where they don't get walked all over or give them additional protection.

Where have you worked?

Yes backstage isn't too bad, but the cables still go in and out very quickly and certainly get tugged around quite a bit. On location is by for the worse, also movie sets pretty bad.

I literally just came off a job where there was a 10m vertical drop. Filming at the bottom, generator at the top. Thick bushes around the top of the drop, how to drop the 125a down? The solution, not surprisingly, was for them to 'gently throw it' over the bushes. And then from the distro below cables over rocks, through windows etc.

I've seen it all, some people do hold a very high standard - mostly it's the venue that demands the standards more than the guys in charge of the show/event, whatever. To be honest the electrical safety, as in testing is second to none. Literally every part of the power distribution is tested by the hire company and then tested as it's laid out. A lot of cables might see 100+ tests a year. It's just the breakneck speed and sheer number of people that makes for a less than ideal final layout quite often.

 

[Darkwood]

No chance, its the way it is backstage everywhere. And on location in TV, cables everywhere. Sometimes it's not so bad in the studio on longer running series but for one day get in, one day get out, it's chaotic. Safety stats however remain very high - make of that what you will.

Each cable/distro is checked/tested as it's laid out and connected at least.

I had industrial dirty factories in my head tbh, I cannot comment on your area but surely all the H&S and trip hazards etc would see cables run safely and out of the way where possible, safety always comes before deadlines athough it is often why accidents do happen when the priorities change position but if you are saying safety stats remain high then fair enough although it will only takes one major accident to see a clamp down on complacent attitudes due to time restraints, the question is though who takes the blame?

 

[gazdkw82]

I think this a real industry problem. I'm pretty new to the Industry and i already see SY installed alot. At my works (university) we use it for all kinds of applications, inverters, controls, commando socket outlets extensions..... Even the large compactor that gets picked up weekly is wired in SY.

I don't think it's obvious enough that it's non compliant. Even our electrical technicians didn't know!

Is there any other piece of electrical equipment that is used so widely and doesn't comply?

 

[Deuce]

I had industrial dirty factories in my head tbh, I cannot comment on your area but surely all the H&S and trip hazards etc would see cables run safely and out of the way where possible, safety always comes before deadlines athough it is often why accidents do happen when the priorities change position but if you are saying safety stats remain high then fair enough although it will only takes one major accident to see a clamp down on complacent attitudes due to time restraints, the question is though who takes the blame?

I think, in all honesty, safety remains high due to common sense. I don't mean H&S common sense, I mean common sense of the people working in the area to realise it's a none standard situation and that extra care is required. Of course in this industry people are used to working fast in the weirdest of places, so it becomes a frame of mind to keep your eyes open.

You would have to work in the industry to understand the way it works, and why it's all thrown together so quickly sometimes. You would be amazed at the sheer amount of kit that's up and running within hours sometimes, easily the equivalent distribution system of a small-medium sized factory.

I can say that on walkways cable ramps are used, but in reality people will be working all over the place.

It's a strange thought these days, but it is possible to be safe just by being aware - you don't actually have to remove a potential risk, just avoid it.

 

[Deleted member 105018]

I was once told that SY has never been rated for power (ie high currents) by an NICEIC quality supervisor. We use it for input/output at 24v for devices close to the PLC on machines unless we’re using ProfiBus. Any power work is done in SWA or manufactured specific cable (Siemens basically demand you use their cable for their servo motors). I’ve also heard on the grapevine that because the braid isn’t always terminated, a damaged cable can cause it to become live. Nevertheless it’s powering my shed!!!

 

[Darkwood]

I was once told that SY has never been rated for power (ie high currents) by an NICEIC quality supervisor. We use it for input/output at 24v for devices close to the PLC on machines unless we’re using ProfiBus. Any power work is done in SWA or manufactured specific cable (Siemens basically demand you use their cable for their servo motors). I’ve also heard on the grapevine that because the braid isn’t always terminated, a damaged cable can cause it to become live. Nevertheless it’s powering my shed!!!

Question is how does the SY get from your house to the shed?

 

[MFS Electrical]

This subject has interested me. What did they change?

Just some words on the spec sheet probably I’ve never seen an SY gland made off properly anyway so it’s probably a good thing

 

[Deleted member 105018]

Haha. If I told you it was buried would you tell me off?

 

[mickfred]

Come across a light wired in SY yeasterdy . Shoved in a 13 amp plug, braid hanging out and very near to going in to the plug . Hate the stuff and should only be able to be sold with correct glands supplied

 

[Silly Sausage]

Haha. If I told you it was buried would you tell me off?

Instrument techs shouldn't be let within a 100 miles of electrical work

 

[Chris1234]

I use it in industry, a lot.
We have a £30k traveling saw, loads of SY.
£2 million extruder, SY connects rotating / travelling parts, and every induction motor on it, rough guess is around 30 of them.
I’ve never found any damaged due to oil etc.

We have maybe 200 cable drops suspended from unistrut with commando plugs on the end in SY, the specific glands make a very strong connection so the cable doesn’t get pulled out. A previous factory also had the same, never had a problem.

One thing to note is you can get overheating where a standard compression gland has been over tightened on it, I’ve seen this a few times.

 

[Darkwood]

I use it in industry, a lot.
We have a £30k traveling saw, loads of SY.
£2 million extruder, SY connects rotating / travelling parts, and every induction motor on it, rough guess is around 30 of them.
I’ve never found any damaged due to oil etc.
.

Are you saying you have SY in a constant flexing motion on a machine here or am I reading this wrong?
You are also saying you install a pvc outer sheath cable in an environment where it is subject to oil?

The difference I would suggest is a cable flexing 1000 - 10,000 times before breakdown and 10million and also a pvc degrading within 2-5 yrs or lasting 20yrs subject to and nature of the chemical oils.

Are you providing a machine that requires costly services every few yrs after warranty of a machine runs out or one that will last, trust me I know the difference just from a visual inspection.

 

[Deuce]

Are you saying you have SY in a constant flexing motion on a machine here or am I reading this wrong?

I was about to say the same thing but in Germany I was once shown around Festo's factory in Stuttgart and their assembly machines used it too.

Constant movement, nothing more than some basic cable support around the glands. I think they were using it's relative inflexibility to support itself and protecting it around the wear points at either end of the cable.

I'm going to be careful now as I was just 23 years old at the time, I may have not judged the situation correctly. However I'm also going to keep an open mind as I see a lot of SY in machine use in Germany (albeit mostly more static) and it wouldn't be the first time the British have scoffed at an idea, and pointed to all the reasons it can't be a good solution.. whilst elsewhere in the world others are using that solution with no problem whatsoever.

The supposed chemical weakness is of particular interest. Is this evidence based? Or just that on paper it could be a weakness, but in real world use it never really manifests as a problem?

 

[Darkwood]

PVC is not good against oils, it is well known and is evidenced based, there was major issues in the past with PVC and bitumen based building materials also other insulating or decorative, this somewhat led to a change in the chemical structure of pvc but it still cannot cope with natural or synthetic oils, you can easily tell because it start to become stiff as the oils leach out the natural plasticisers in the pvc.

I design controls for machines and the wiring to boot, I have to use specialised cables to suit too like used in energy track where they are designed for repeated constant movement, I spec'd some of my jobs to give a service life according to the manufacturers details of 10 to 15yrs with flexing in the million+, some of them are still going after 20yrs.

I can tell you from experience that I seen SY used to do the same and it barely makes a yr on frequent flexing and is why it is not designed for it, I can cite you all the info from companies like Lapp or Igus who make these cables and have spent 100,000's designing and proving their products ...

SY is snake oil to the electrical industry, it has been pushed and promoted by non electrically minded sales people to ignorant professionals that it is a wonder solution but like expressed before, it is not recognised by BS standards and is misused so much it is worrying for the industry as a whole.