what do you call the "armour" in SY cable

[SUNRAY]

I use it often at work, I have built equipment that uses upto 11 core SY cable, we stock upto 24 core.
Used as equipment wire it's OK, when some numpty then grabs some to power an external aircon unit then problems can arise and a proper electrician then has to step in and change it to SWA

At a previous workplace we used to use it for the foot pedal wire to a big bending machine etc. Worked well until a sheet of steel was dropped onto it and then you could easily see the damage.
I have seen (and used) those SY glands with the slot in, don't bother with them any more and just use a plastic gland and take the outer core direct to an earth bar instead.

Best bit of advice as they cut the screen wiring as tightened. If your realy do want a brass fitting use SWA gland.

In this instance the screen wasn't to be connected at this end. At the other end

screen was unwoven, formed into a tail, green/yellow sleeved and crimped into a yellow ferrule, sorry no internal pic of the dimmer pack.

 

[crystal ball]

We used to use Lewden glands and clamp the braid doubled over the sheath

 

[SUNRAY]

We used to use Lewden glands and clamp the braid doubled over the sheath

Something like this presumably

 

[crystal ball]

Something like this presumably
View attachment 331342

That's them

 

[SUNRAY]

That's them

Yes I've seen it done many times. I'm not keen as the electrical termination is relying on the pressure against the soft insulation/sheath and any flexing movement is likely to disturb the connexion. I've known the vibration of a metal guillotine shake it loose, which is the same issue I've found with the proper SY glands with the split.

 

[crystal ball]

Yes I've seen it done many times. I'm not keen as the electrical termination is relying on the pressure against the soft insulation/sheath and any flexing movement is likely to disturb the connexion. I've known the vibration of a metal guillotine shake it loose, which is the same issue I've found with the proper SY glands with the split.

It can happen with any gland on a vibrating machine

 

[SUNRAY]

It can happen with any gland on a vibrating machine

Yes but less likely with a soft clamp, such as a stuffing gland.
I know the proper SY gland has an 'O' ring but the way it's implemented is more of a seal than a clamp whereas a SWA gland has a stuffing action.

 

[crystal ball]

Yes but less likely with a soft clamp, such as a stuffing gland.
I know the proper SY gland has an 'O' ring but the way it's implemented is more of a seal than a clamp whereas a SWA gland has a stuffing action.

Mebbe, mebbe not, seen it happen all ways round

 

[SUNRAY]

Mebbe, mebbe not, seen it happen all ways round

Oh yes, me too.

 

[crystal ball]

Worked in a factory where SWA glands kept working loose, it was blamed on the nearby railway line sending vibrations through the ground, I blamed the previous sparky who never tightened glands properly

 

[SUNRAY]

Worked in a factory where SWA glands kept working loose, it was blamed on the nearby railway line sending vibrations through the ground, I blamed the previous sparky who never tightened glands properly

One of the sub contracters I used to get to work with was like that, he used to tighten the 2 halves together with 2 massive AJ's but the nut holding it to the enclosure was usually a smidge more than hand tight onto the burr left by the Starrat cutter. By the time he'd finish dressing the cable it would be loose.

One place I worked had RCD tripping issues, but the old type with earth wires, when a train went past. Initially we were trying to blame vibration but finding volts between earth wiring in a building and the ground outside we tried 2 probes in the ground maybe 200m apart and could see significant voltage between them when a train passed.

 

[robinbanks]

I see that RS states it is a control cable. as such - weird that it is sold in fairly high cross-ssectional areas.

But if used in a low voltage DC context a large CSA would be desirable for the higher CCC?

 

[bernardgreen]

we tried 2 probes in the ground maybe 200m apart and could see significant voltage between them when a train passed.

Back in the 1960s two friends set up a telephone connection between their houses either side of a railway line. They used two pairs of ground rods, one each side of the tracks and modulated carrier frequency . Inefficient in terms of power but it worked while the trains were steam or diesel hauled. Electrification killed it with several volts being induced in the rods by traction current flowing from the track and through the ground back to the substation. Improvements to the traction system added a return conductor along the track to reduce the current through the ground. This significantly reduced but did not eliminate the interference.

 

[crystal ball]

I worked in Cathodic Protection in Sydney, one of our pipelines more or less followed rail lines to Botany, stray currents from the railway system played havoc with the CP, drainage bonds were connected between the pipelines and rail track to mitigate the effect We carried out regular surveys with voltage chart recorders and it was normally a pronounced zig zag except during frequent train strikes when it was a flat line