SY, CY None Compliant????

[Jay Sparks]

So, I'm out on site the other day and the apprentice is installing some SY cable for a ring final circuit. Anyway, we got chatting and he mentions that this type of cable does not comply with BS7671! I said, "of course it does, it's part of the AM2 and it is one of the 7 cable types of the new 2357 apprenticeship NVQ! So out of curiosity I had a look. To my suprise, it does state in the BS7671, that this type, along with YY, CY are none compliant!! I know that most of this multi-core cable comes with none standard colour cores etc but does any one know an actual reason why it is none compliant? I am genuinely interested.

Cheers

Jay

 

[Risteard]

It's to VDE standards.

 

[Jay Sparks]

It's to VDE standards.

But why is it in the AM2 and NVQ? Boggles the mind!!

Jay

 

[Risteard]

But why is it in the AM2 and NVQ? Boggles the mind!!

Jay

LOL. Can't answer that. It wasn't in the AM2 when I did it.

Is it being used for controls or what in the AM2?

 

[Jay Sparks]

LOL. Can't answer that. It wasn't in the AM2 when I did it.

Is it being used for controls or what in the AM2?

Yeah the motor and DOL starter. But it is also in the list of 9 cables for the 2357. Strange! I assumed that it was because the conductors were mainly all black and had to be taped/sleeved but then someone mentioned it might because it isn't BASEC compliant (or whatever it is)lol

Jay

 

[Adam W]

I know it's not considered suitable as an "earthed metallic sheath capable of withstanding penetration by a nail or the like" or however the regs word it, but I find it hard to believe it's been 'banned' altogether.

 

[Simonslimline]

Out of interest, why was SY the choice of cable for an RFC?

 

[Darkwood]

SY and CY were been used as an all round armoured cable by thousands of sparks when it isn't suitable, rather than list the uses it is OK for which is few they seem to make life easy to just say no.... seen plenty of live un- earthed braid on this stuff over the yrs ... apparently the Regs are getting so dumbed down to cater for the idiots. ..:sad3:

 

[davesparks]

So, I'm out on site the other day and the apprentice is installing some SY cable for a ring final circuit. Anyway, we got chatting and he mentions that this type of cable does not comply with BS7671! I said, "of course it does, it's part of the AM2 and it is one of the 7 cable types of the new 2357 apprenticeship NVQ! So out of curiosity I had a look. To my suprise, it does state in the BS7671, that this type, along with YY, CY are none compliant!! I know that most of this multi-core cable comes with none standard colour cores etc but does any one know an actual reason why it is none compliant? I am genuinely interested.

Cheers

Jay

I believe it is perfectly acceptable to use it if it is suitable for the job with respect to its specific properties and if those properties are required, which is pretty much the same as any cable.
SY is designed for, and has the properties required for, control circuits and power circuits such as the output of a VFD where good EMC screening is required with some vibration resistance indoors and where a low level of mechanical strength is acceptable.

Off the top of my head one regulation which could be used to prevent its use for general installation work would be the one which requires that flex used in a fixed installation be of the heavy duty type such as H07-RNF.


I know of one installation where I had to remove and replace with SWA some SY installed by someone else following a local authority inspection where they flagged it up. At the same place I also had to remove some FP200 which had been used to extend and MICC circuit and replace it with MICC.

 

[davesparks]

SY and CY were been used as an all round armoured cable by thousands of sparks when it isn't suitable, rather than list the uses it is OK for which is few they seem to make life easy to just say no.... seen plenty of live un- earthed braid on this stuff over the yrs ... apparently the Regs are getting so dumbed down to cater for the idiots. ..:sad3:

It became popular in theatre/events (particularly sound companies) a couple of years ago, and it is thoroughly unsuitable for that job! To the point that it has been specifically written in to BS7909 that SY and blue arctic are not to be used outdoors. And I think IIRC it advises against the use of SY scull stop

 

[Jay Sparks]

Out of interest, why was SY the choice of cable for an RFC?

It's in a garage/body shop and I think the customer had loads of reels spare!!

 

[Andy78]

FWIW I have done a bit of internet research

Basec article on control cable and it's compliance from 2013
BASEC - British Approvals Service for Cables

The above article references regulation 511.1 of BS7671 which states that all equipment shall conform to a current BS or BS EN standard.

Looking at manufacturer's websites, some state that their control cable conforms to BS EN 50525 (or parts of it) which has superseded BS 6500. Some only claim their cables meet VDE standards and no others, and are not to be used in fixed wiring installations designed to comply with BS7671.

I think this industry wide discrepancy, and the dumbing down due to historical improper application of this cable as DW says, are both responsible for the blanket advice to avoid use of this cable.

 

[Jay Sparks]

Make of this what you will!



Only states it "discourages" us from using it. And as Andy has said above, move manufacturers state that their cab;le confirms to SOME parts but not all!

Jay

 

[Andy78]

Make of this what you will!

View attachment 32168

Only states it "discourages" us from using it. And as Andy has said above, move manufacturers state that their cab;le confirms to SOME parts but not all!

Jay

What I meant by that was that BS EN 50525 has sub divisions. Some manufacturers claim compliance with one of these sub divisions, such as BS EN 50525-2-11, which in itself is an entire standard and as such would be compliant to use under BS7671 if following the advice of the manufacturer.

The OSG advice could be deemed as misleading if such BS EN standards are being met in the production of control cable.

 

[SheffSimon]

I believe it is perfectly acceptable to use it if it is suitable for the job with respect to its specific properties and if those properties are required, which is pretty much the same as any cable.
SY is designed for, and has the properties required for, control circuits and power circuits such as the output of a VFD where good EMC screening is required with some vibration resistance indoors and where a low level of mechanical strength is acceptable.

Off the top of my head one regulation which could be used to prevent its use for general installation work would be the one which requires that flex used in a fixed installation be of the heavy duty type such as H07-RNF.


I know of one installation where I had to remove and replace with SWA some SY installed by someone else following a local authority inspection where they flagged it up. At the same place I also had to remove some FP200 which had been used to extend and MICC circuit and replace it with MICC.

Poor EMC screening from SY, the braiding is full of holes, and it's supposed to be a control cable, not a power cable.

 

[hightower]

I was at a famous north east open air historical museum a few months ago, and I noticed all their bulkhead lighting to illuminate the paths (attached to wooden fences) was run in what looks like SY. I didn't spend too long thinking about it actually until I've seen this - so I'm guessing this cable is totally unsuitable for this use? I don't go often, but worr lass is there plenty with the bairn so I will get her to take some photos next time.

 

[Andy78]

I was at a famous north east open air historical museum a few months ago, and I noticed all their bulkhead lighting to illuminate the paths (attached to wooden fences) was run in what looks like SY. I didn't spend too long thinking about it actually until I've seen this - so I'm guessing this cable is totally unsuitable for this use? I don't go often, but worr lass is there plenty with the bairn so I will get her to take some photos next time.

I have seen SY installed outdoors before. Only a matter of time before the transparent outer cracks due to it's lack of UV resistance, water gets in, and the whole cable turns black with filthy mouldy moisture trapped next to the screen.

 

[hightower]

I have seen SY installed outdoors before. Only a matter of time before the transparent outer cracks due to it's lack of UV resistance, water gets in, and the whole cable turns black with filthy mouldy moisture trapped next to the screen.

Yeah, but in this instance I think the SY might actually go under ground at points, so wonder if they think it counts as armoured. Will get some photos.

 

[Andy78]

Yeah, but in this instance I think the SY might actually go under ground at points, so wonder if they think it counts as armoured. Will get some photos.

Certainly not suitable for direct burial. I wouldn't install it in duct either myself. Probably does not conform with the regs for buried cables as it is.

 

[ruston]

I agree, it is only suitable for 'friendly' environments , although some manufactures claim that theirs is suitable for outside use.
Personally I would not do this. Horses for courses.

I would certainly not consider burying it direct.

 

[HappyHippyDad]

So, I'm out on site the other day and the apprentice is installing some SY cable for a ring final circuit. Anyway, we got chatting and he mentions that this type of cable does not comply with BS7671! I said, "of course it does, it's part of the AM2 and it is one of the 7 cable types of the new 2357 apprenticeship NVQ! So out of curiosity I had a look. To my suprise, it does state in the BS7671, that this type, along with YY, CY are none compliant!! I know that most of this multi-core cable comes with none standard colour cores etc but does any one know an actual reason why it is none compliant? I am genuinely interested.

Cheers

Jay

Could you point me to the page or reg of BS7671 where it says this JS? I'd be interested to read it, thanks.

 

[GEOFF S]

Could you point me to the page or reg of BS7671 where it says this JS? I'd be interested to read it, thanks.

Hi

Im pretty sure its comes down to the braided screen not meeting the relevant requirements for mechanical protection, also probably issues with regard the braid and fault current.

Cheers

 

[shanky887614]

go be honest as long as its used inside and it doesnt require mechanical protection 3c (L,N,E) sy is fine.

to be honest most of it ive used has been in trunking from vsd's to motors with a stuffer out of the trunking then into the motor case

Sent from my SM-G935F using Tapatalk

 

[davesparks]

Could you point me to the page or reg of BS7671 where it says this JS? I'd be interested to read it, thanks.

Somewhere there is a reg which says that heavy duty flex is to be used for installation work, and SY doesn't fall in to that category

 

[Adam W]

.... seen plenty of live un- earthed braid on this stuff over the yrs ...

I've found loads of this at my place, which was installed by the mechanical guys. It gets my goat - why even bother if you're not going to earth the braid? You may as well just use H05.

IMO SY has it's uses, such as where you need something more flexible than SWA but there is a danger of someone going through the cable with anything - if the sheath is earthed contact will be made with that before a live conductor so the protective device should operate.

 

[Flanders]

I thought the brade was for a screen and not designed to carry a fault current thats why is has a seperate cpc within the cable.

 

[Davisonp]

Somewhere there is a reg which says that heavy duty flex is to be used for installation work, and SY doesn't fall in to that category

[h=5]521.9 Use of flexible cables[/h]521.9.1 A flexible cable shall be used for fixed wiring only where the relevant provisions of the Regulations are met. Flexible cables used for fixed wiring shall be of the heavy duty type unless the risk of damage during installation and service, due to impact or other mechanical stresses, is low or has been minimized or protection against mechanical damage is provided.
NOTE : Descriptions of light, normal and heavy duty types are given in BS EN 50565-1.

 

[Adam W]

I thought the brade was for a screen and not designed to carry a fault current thats why is has a seperate cpc within the cable.

You can have a separate CPC within an SWA, but the armour should still be earthed.
Either way the braid of SY flex should be earthed.

 

[davesparks]

I've found loads of this at my place, which was installed by the mechanical guys. It gets my goat - why even bother if you're not going to earth the braid? You may as well just use H05.

IMO SY has it's uses, such as where you need something more flexible than SWA but there is a danger of someone going through the cable with anything - if the sheath is earthed contact will be made with that before a live conductor so the protective device should operate.

But the braid is not rated for the fault current, so it is pretty much the same as installing PVC insulated and sheathed flex as far as any protection goes.

 

[davesparks]

You can have a separate CPC within an SWA, but the armour should still be earthed.
Either way the braid of SY flex should be earthed.

Earthed yes, but it cannot handle fault current so cannot be used to provide any protection such as that provided by SWA, MICC or any bs8436 cable

 

[ruston]

Well , here is an overview from Eland Cables on SY.
It may answer a few of the questions.
SY Cable | Eland Cables

And a manufacturer that says it can be used outdoors if it is protected.
It's all down to researching the product to suit what you need

http://uk.rs-online.com/web/p/sy-cable/0522531/

 

[SheffSimon]

But the braid is not rated for the fault current, so it is pretty much the same as installing PVC insulated and sheathed flex as far as any protection goes.

Thats because its a control cable, not a power cable.

TBH I can't think of a situation where I would spec or accept SY.

 

[Adam W]

Earthed yes, but it cannot handle fault current so cannot be used to provide any protection such as that provided by SWA, MICC or any bs8436 cable

I see. So what would happen if for example you were to go through the earthed braid with a grinder or a chisel or something, and into the live conductor?

 

[davesparks]

I see. So what would happen if for example you were to go through the earthed braid with a grinder or a chisel or something, and into the live conductor?

Subject to a few variables the two likely outcomes are:
1 the braid melts before the ocpd clears the fault
2 the ocpd clears the fault before the braid melts.

Firstly if an rcd is in use then it should clear the fault.
If the fault current is high enough to cause instantaneous operation then scenario 2 is likely.
If the fault current is low enough that the ocpd does not operate instantaneously then situation one could occur.
Both options could easily result in a cloud of vapourised molten metal

 

[LeeH]

Also consider most people just use stuffers and peel back a few strands. So Daves option 1 the most likely.

 

[Midwest]

Used miles of the stuff back in my days in the car factory, for conveyor systems etc. It was specified then, as it provided more of a durable cable than heavy duty flex. Guess approved practises change over time, probably end up with twin & earth being 'discouraged' in due course.

 

[i=p/u]

Seeing quite a bit of everyday and guess what it's never earthed..
most used for em stops and motors.

 

[Spoon]

We sometimes use SY for power between the power dist board and other equipment in the installation. Only when SWA is not needed.
I contacted Eland to see what they thought and below is their response: They responded really quickly which is always great and I have ever had a problem with these people.

Themain issue is that YY and SY cables are being applied incorrectly, for exampleYY cables have been installed as a replacement for Twin & Earth, SY cableshave been used in direct burial applications as a replacement for SWA. Theadvice given is that cables used for compliance with BS 7671 need to complywith a published British Standard, or UK adoption of a CENELEC standard. Thiswill depend on the installation.

With regards not using SY and YY cables in fixedapplications , the reasoning behind this is given within the new onsite wiringguide published by IET is that the SY and YY cables have not been made to aspecific standard.

There have been a number of articles published by BASEC, NICEIC and ACIregarding the use of YY, CY and SY cables, the articles identify that thesecables are not included in BS7671 and are therefore could potentially not be fit for purposeas fixed wiring cables, please find below links:
http://www.basec.org.uk/News/BASEC-News/Be-Cautious-of-Midleading-Claims-Associated-with-YY-and-SY-cables
http://www.aci.org.uk/news/aci-issues-warning-installers-over-cable-claims

 

[westward10]

Just because something is not recognised by BS7671 it does not mean you cannot install with it. The cores of this cable, apart from the cpc may well all have black insulation but they are numbered.

 

[High Tower]

I would always be selective about where i use SY, last time i used it was for temporary lighting within a semi derelict building. all clipped to the ceiling out of harms way.

And when i used to do the very odd few houses i would use YY to connect cookers to the outlet plates. apart from that dont use the stuff.

Tell a lie, used some YY the other day to flex up a couple of UPS's