SY Cable containment

Because it doesn't actually neet any UK or harmonised standard.  Once you start allowing non-standard cable to be used, how do you define what's acceptable?

to say it meets no standard is not quite fair. There is a makers specification,  and consider Eland's example, made to VDE0250 and tested to a few  other relevant standards as listed in that datasheet. The problem is twofold, DIN  only standards are not 'harmonised' - it would need to be a  "DIN EN" rather like "BS EN", so the standards are German only,  (which has implications for who can test it and what 'sign it off' means in other jurisdictions ) and that in the makers data sheet, the braid resistance is not guaranteed.

But it is certainly not made to a random uncontrolled recipe.

Mike

It seems to me that SY is being considered "the same as" flexible SWA. This is not true as the braid is mechanical protection only and is not suitable as the CPC. SY cables with mains colour cores have a G/Y core too, it is those that are aimed at LV control functions that may not. Therefore the resistance of the hard steel braid is not a consideration, and it is likely that a penetrating nail will simply burn up the surrounding braid, It does provide considerable extra protection from knocks and sharp objects etc. compared to soft sheathed cable

Given that it is a well-established specification with national standards that are relatively stable for a product that is de facto used (and abused) widely beyond those standards' jurisdiction... do we know why CENELEC haven't adopted them to be ENs?

Surely there is a call for it, manufacturers would benefit, and presumably not a lot of work if it is adopting existing documents! So there must be a reason...?

Politics I suspect, because the process is, that following the decision of the European Council, new EN standards must be adopted and implemented immediately and without changes in the member states, and, at the same time, the corresponding national standards get withdrawn. Do not underestimate the no of man hours involved in a pure administrative task like translating DIN documents into French. But I agree, some rationalising is long overdue. The same is true of NYM-J and a few others. (NYM..    NYY)
Mike

Politics is always the trouble Mike. SY and YY are widely used in Germany, the French like flexible conduit! There you are at once, Non, non, non! SY in the UK is made to BS6500, similar to all out flexible cables, so where is the problem? I know, they cannot agree the braid wire size and type! LOL!

To be honest even if it was a private standard - if only such and such a maker stated their braid is so many ohms per hundred metres and so many strands of diameter dd or an I2t fusing figure of the braid stranding and or a degree of optical coverage it would be a lot easier - we could then just specify use cable from such and such's .

Mike

David Stone said:

This is not true as the braid is mechanical protection only and is not suitable as the CPC.

That is not true ... the braid of SY is mainly for screen, for EMC purposes, and offers little or no mechanical protection, certainly in comparison to the armour of a cable. If there is a sheath beneath the braid, it may offer some additional protection to that sheath, in terms of protection against scuffing or cutting, of a fashion, but not penetration as with armour ... but I guess that is why we could do with a proper constructional standard for these cables.

David Stone said:

SY cables with mains colour cores have a G/Y core too,

SY cables with black cores adopting numeric core identification also have GNYE core (Note GNYE is the correct abbreviation, see Amendment 2 - but this is not new, the two-letter colour code, with 4 letters used for bi-colour, was originally harmonized many years ago, and was published shortly after harmonization as BS 7645:1993 !).

For information, 2 core power cables are available without GNYE cpc ... and auxiliary (control) cables can be purchased that have a GNYE cpc ... perhaps because, as well as the fact that LV could be used for controls, PELV is preferred in Machinery (as defined), and the cpc would be run between all points.

David Stone said:

Therefore the resistance of the hard steel braid is not a consideration, and it is likely that a penetrating nail will simply burn up the surrounding braid, It does provide considerable extra protection from knocks and sharp objects etc. compared to soft sheathed cable

Not true, and it is not the function of the braid. It is only the fact that the cable is sheathed, which prevents the braid from having to be a protective conductor ... and perhaps that's another discussion point as to why the guidance on BS 7671 advises caution, regards accidental penetration of the cable in certain environments.

Simon Barker said:

Once you start allowing non-standard cable to be used, how do you define what's acceptable?

All it would take is for the manufacturers to make a cable constructional standard for CY, SY and YY, and many of the problems would be resolved ... all that we would have to do is make sure we pick power cables for power wiring, not auxiliary cable (sadly, another issue is because a lot of the products have, in the past, not been marked, we can't always verify by inspection that the CY, SY or YY cable is actually rated as a power cable, rather than an auxiliary cable - but that could also be remedied by having appropriate marking requirements included within the constructional standard).

The thickness of the wire in the braid is absolutely vital,  the thickness of the braid wires makes the difference between the braid going off like an old fashioned camera flash bulb or carrying the fault current and allowing a fuse to disconnect the current.

Have you never set fire to wire wool?