SY Cable? Thoughts?

[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.

 

[Deuce]

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.

In such circumstances, could sy cope for 1 year without issues? In a single years use is there a concern about oils and subsequent breakdown?

 

[LeeH]

Just to add my 10p

SY (and CY) is a pretty poor cable for EMC compatibility too (VSDs) as the screening is usually extremely poor (full of holes) and it’s impossible to buy it in a concentric formation ie 3 core.

So it’s no good for anything basically but the AC boys cannot get enough of it.

 

[Darkwood]

In such circumstances, could sy cope for 1 year without issues? In a single years use is there a concern about oils and subsequent breakdown?

When you design a machine and its controls and cabling you sell it on the premise it is of good design and service is minimal and not too costly, in answer to your question then I would need to know the travel, the duty of flexing and the usage of the machine but regardless of this SY is not a cable designed for constant repeated operational flexing, I will provide a link to show you how much tech' goes into energy cables (constant flexing cables)..just an example of many companies out there I use that you don't get at you average wholesalers ...https://www.igus.com/contentData/wpck/pdf/US_en/7 guidelines for continuous flex cables.pdf

 

[Darkwood]

Just to add my 10p

SY (and CY) is a pretty poor cable for EMC compatibility too (VSDs) as the screening is usually extremely poor (full of holes) and it’s impossible to buy it in a concentric formation ie 3 core.

So it’s no good for anything basically but the AC boys cannot get enough of it.

You are correct for the most of your comment but weirdly some VSD manufactures promote and accept the use of SY cable as a solution, the issue is the quality, most SY has loose wound braiding, the ones they suggest has compact tight braiding ...easy to tell in that it is impossible to unravel the braiding on the good stuff without time and determination although the correct expensive glands should be used anyway.

 

[LeeH]

The only time I’ve seen a decent SY braid was on a project in Holland when the customer requested all cabling had to be from LAPP.

Everything I’ve seen from the normal wholesalers has more holes in it than a sieve.

I’m aware some manuals state it can be used but the fact you cannot buy it in 3 core, it’s poor steel braid makes in useless especially on large motors.

I’d rarther (and have) use SWA. But that has its own issues as you cannot terminate that directly into the drive.

 

[suffolkspark]

You can buy it in 3core?
Just a note rode wickerman at alton towers in the summer.... Theyve used it for all the speaker cabling and at thorpe park there was an abundance of it on the ride controlls of swarm

 

[netblindpaul]

The only time I’ve seen a decent SY braid was on a project in Holland when the customer requested all cabling had to be from LAPP.

Everything I’ve seen from the normal wholesalers has more holes in it than a sieve.

I’m aware some manuals state it can be used but the fact you cannot buy it in 3 core, it’s poor steel braid makes in useless especially on large motors.

I’d rarther (and have) use SWA. But that has its own issues as you cannot terminate that directly into the drive.

The thing with SWA is that it is not suitable for EMC screening that drive cables will require.
This is a known issue with SWA & drives, and has been proven with EMC testing and analysis.

 

[Midwest]

I installed SY cable in the car factory in the 1980’s. It was used on conveyor systems etc. I know the paint shop install I worked on is still there, wonder if the cable is?

 

[suffolkspark]

Played crazy golf last week and it had been used everywhere on the course which is only a few months old! Chucked in the water features and laying on gravel and all in sunlight, ill give it a couple of years! Its been used everywhere! outside lights etc all in compression glands! Bloody abortion

 

[Tes369]

Nothing wrong with the stuff at all if your mindful of its limitations like any other cable.

*I'm not agreeing with the post above.