How will you proceed with this ? Will you have the cable replaced as it’s unsuitable and does not comply with UK standards?

Doncaster Cables advises against the use SY as power cables. Do we Stick to manufacturer’s recommendations?

That video also seemed to say that no-one makes SY in the UK any more ... but Doncaster (according to their web site) only have one manufacturing facility (in Doncaster) - so is their SY UK made or not?

Even their Web page for SY says it's rated for 300/500V, generally meets  BS EN 50525-2-11 (i.e. the standard for mains flexes) and even goes as far as saying  "This cable is also used by electricians in certain fixed installations where only light mechanical stress may occur. " which doesn't feel like an official condemnation.

So still as clear as mud. What's needed is for a proper standard to cover SY (and CY) cables.

   - Andy.

I'm inclined to agree - to set the UK ghosts to rest, although the rest of the continent does not seem so worried,  there probably needs to be a BSI type standard defining the minimum CSA of the copper, the voltage withstand of the insulation core to core and the core to braid, and then the maximum braid resistance per unit length and perhaps for us EMC obsessed types, the braid optical coverage fraction.
In reality I've yet to be delivered any that was unsafe to use or failed on insulation tests.

For a bit of  laugh, as we have the facility, we have from time to time subjected cable samples to gross over-voltages to see the true breakdown behaviour, and it is always many times the test limits - think  high 10s of kV - it is the air spacing at the exposed ends that is the point of breakover in all normal mains connectors.

And yes, that video short is slightly at odds with the written word on their website.

Mike

Voltage rating of wires is an interesting topic. It is typically determined by testing samples over a range of voltages and recording the time to failure. The results are then plotted to determine the long term withstand voltage. A factor of safety, to allow for manufacturing defects and tolerances, is then applied. A piece of typical PVC equipment wire will have a short term withstand of 20kV or more, a long term withstand of around 6kV and a rating of maybe 600V. It’s not a precise science. The minimum insulation thickness is more often determined on mechanical rather than electrical grounds.

This reminds me of that thread I created

BS7671 says refer to MI

engx.theiet.org/.../142399

Mike, you should only use SY,YY,CY cable for control, not power circuits as the insulation is substandard and not to any standard at all

Mike, you should only use SY,YY,CY cable for control, not power circuits as the insulation is substandard and not to any standard at all

What's your thinking behind that? Does a 230V control circuit require lesser insulation than a 230V power circuit?

   - Andy.

David,

Where are you getting your information? Do you have any references?

I had a look at one of our local suppliers to see what they said:

1964724_1_eng_tds.pdf

This shows that the materials are in accordance with British Standards. In the construction tables the wall thicknesses look reasonable for 300/500V (where is a higher rating required in normal use?)

Is this a real problem?

Roger,

without knowing the cable you have the table for, you need to get the manufacturers data, and they will say "for control functions" they don't say for Power circuits to carry load, take a look at Elland cables and the docs online for instance, then theirs BS7671 telling all not to use for power circuits, without going into lots for BS EN numbers and checking everything, why would anyone install a cable that may not comply? when there are many others available? it doesn't make sense accepting this risk

Also in the table you have above, the first line - its designed for control uses, but some electricians use it for others things!!!! 

yes it does, a control, circuit generally doers not carry load consistently, and the manufacturers of the said cable say its for Control functions 

I am not sure where this ‘control cable’ comes from, maybe from the European manufacturers.

The Lapp Cable (German manufacturer of SY type cables) website states:

“Different conductor cross-sections and numbers of cores are required depending on the intended use.

Most cables for standard applications are at least two-wire and start at 0.5 mm2. For control cables (core identification is usually by numbers), the number of cores can be 50 or more. The maximum conductor cross-section is often 2.5 mm2, but can be higher depending on the type. Power cables (core identification is typically by colour) can also be found in this product group with four cores with a conductor cross-section of up to 240 mm2.”

https://e.lapp.com/apac/c/cables-and-wires/power-and-control-cables/cables-for-standard-applications/pdm_atr_parent_product_filter-olflexr_classic_110_sy

Various voltage ratings are also offered:

“Within the product group, choose between cables with 300/500 V, 450/750 V or 0.6/1 kV.” (from the same web page).

The Olflex cable are also supplied with CE and UKCA certification:

 PDF

PDF

Here under documentation:

https://e.lapp.com/apac/p/cables-for-standard-applications/oelflex-classic-110-sy-4g1-5-1125304

People may be using the wrong versions of SY cables, but there is nothing inherently wrong with the product.

I tend to think there are more things wrong with the UK wiring standards:

       Installation cable with uninsulated reduced size cpcs.

       Ring final circuits which allow overloading of cables.

       BS 1363 fused plugs which are both prone to overheating and are a mechanical hazard in several ways.

I am not sure where this ‘control cable’ comes from, maybe from the European manufacturers.

The Lapp Cable (German manufacturer of SY type cables) website states:

“Different conductor cross-sections and numbers of cores are required depending on the intended use.

Most cables for standard applications are at least two-wire and start at 0.5 mm2. For control cables (core identification is usually by numbers), the number of cores can be 50 or more. The maximum conductor cross-section is often 2.5 mm2, but can be higher depending on the type. Power cables (core identification is typically by colour) can also be found in this product group with four cores with a conductor cross-section of up to 240 mm2.”

https://e.lapp.com/apac/c/cables-and-wires/power-and-control-cables/cables-for-standard-applications/pdm_atr_parent_product_filter-olflexr_classic_110_sy

Various voltage ratings are also offered:

“Within the product group, choose between cables with 300/500 V, 450/750 V or 0.6/1 kV.” (from the same web page).

The Olflex cable are also supplied with CE and UKCA certification:

 PDF

PDF

Here under documentation:

https://e.lapp.com/apac/p/cables-for-standard-applications/oelflex-classic-110-sy-4g1-5-1125304

People may be using the wrong versions of SY cables, but there is nothing inherently wrong with the product.

I tend to think there are more things wrong with the UK wiring standards:

       Installation cable with uninsulated reduced size cpcs.

       Ring final circuits which allow overloading of cables.

       BS 1363 fused plugs which are both prone to overheating and are a mechanical hazard in several ways.

No UK approved body has tested or accepted the UKCA