Advice reqd re SY cable

[Hefferl]

I've been asked to do job where I will be supplied with SY cable (This is a PV installation). I've not used this before and so need some advice on the following points please:

(1) This cable is to be used outside but I was under the impression that this cable is not suitable for outdoor use (i.e. in direct sun or in wet conditions). Is there a variation available that is suitable for outdoors?

(2) How does this cable have to be terminated? i.e. which glands to use and is it necessary to earth the cable braid?

(3) When trying to determine the current carrying capacity of this cable what will it be called in the tables in the BRB?

(4) Is there anything else I should be considering when using this cable?

Many thanks!

 

[Evans Electric]

SY cable have their own brass glands that will connect the braid to earth , they are however rated as indoor ,moisture proof , perhaps you could use an SWA shroud.

I can't see them in the BRB, I have them in specialist booklets but the current ratings seem to be a state secret .

They are called ...Multicore Flexible Control Cables (SY) Biggest I've seen is 6mm X 7core.

 

[kme]

OK.

1. As far as I am concerned, it is fine for external use, I`ve used it externally on buildings for PV supplies.

2. Either GXD glands (with a split into which the braid can be fixed), or standard 20mm stuffing glands - separate the braiding, and sleeve g/y. I would use the braid as a supplemental cpc; you`d want it earthed at supply end anyway, so may as well do it the other end, too

3. I`d use multicore, non-armoured tables. Assuming you`ve got 4mm 3 core, on a domestic, with a B16 OCPD - you`re unlikely to have any problems.

4. Use a small, flat-blade driver to separate the braiding - and try not to cut the braiding when removing the sleeving. The PVC cover (inner and outer) isn`t very thick - its quite easy to slice into the braid (when removing outer sheath), or the inner cores (when removing inner sheath).

Regarding the glands - if you can securely clip the cable, so no strain is on the terminations - use the stuffing glands. Otherwise, GXD is the best route, IMO.

KME

 

[Evans Electric]

OK According to MI5 :-

0.75mm 12A

1.0 15

1.5 18

2.5 26

4.0 34

6.0 44

Also spotted a note that read " This cable is not suitable for connection to the public system" Don't know what thats all about !!!

 

[Hefferl]

KME / Deke - thanks for your good advice it's appreciated.

Lee

 

[kme]

You know where the "scoob" button is located

 

[hxsarge]

They do almost every size of sy, we have installed a 25mm 4c as a sub-main at a customers request, much prefer armored though, not keen on running sy in vulnerable conditions due to the low mechanical protection. Just a note on the using stuffing glands, try un-thredding a meter of braiding to reach an earth bar at the other side of a control panel, pain in the a**! When i did my am2 about 6 months ago i was told by the guy at the center that the only way the exam boards saw as acceptable was to use an sy gland with a monical and an earth wire to the earth terminal, much easier as you only have to strip off an inch of braid. Hope this helps!

Andy

 

[loz]

here is a very good link on terminating sy cable The Practical Skills Series : Cable Termination - SY Flex ["Electrical Jobs" / Electrician] - YouTube