So today's little job on a NEW BUILD

[kerching]

Phone call..."we have moved a wheel  free 2 post ramp. It won't work. Talked to an expert who says you need to calibrate and synch the two drive screws otherwise the limit switch kicks in"....it's beyond our electrician

so I turn up, take cover off and there is a mini data disc inside and a USB port!   WTAF.?     That's beyond my pay grade 

So I think, "well I'm here may as well have a go" they have paid me to turn up ( only 10 min drive away )

check supply.....all 3 phases there

cannot see control voltage on contractors but I'm pretty sure it ain't 415 and there isn't a transformer

then I spot the neutral connection where there are 2 going out and non in

somebody forgot the neutral

checked 4x4 box on side...no,N

checked ISO on wall....no N......and it's a 4 core SWA in a plastic iso 

Blue  has been used as an earth ...

so,when this is converted back to a N there is no earth continuity across the iso

so I proved to them that it 'would' work correctly when it had a neutral

so now their spark has to go back to sort it out as well,as.....

fitting correct glands to all the SY flexes for final connection

NOT using the SY as  an earth

possibly changing a lot of SY final connections as every one I saw went into a plastic gland

fitting  some SS cable ties on cable trays....not a one in sight

hey ho....not my problem

any money he just fits banjos on the SWA at the plastic ISO s

 

[Andy™]

or more likely itll be made TNC in the control panel....

 

[Tony S]

That would be funny if it wasn't so true.

 

[Sharpend]

what an excellent spark!!

I'll let you decide to whom I refer!

 

[kerching]

They are still in the process of moving into this new building and I suspect that every isolator is 'similar'

I hope they don't require a lot of neutrals

bulk purchase of Piranha nuts anyone?

:Hitsthefan:

 

[Andy™]

They are still in the process of moving into this new building and I suspect that every isolator is 'similar'

I hope they don't require a lot of neutrals

bulk purchase of Piranha nuts anyone?

:Hitsthefan:

probably dont know what they are

if i install a supply for a machine thats 3 phase no neutral, i still fit a neutral. for the extra cost, it saves a lot of hassle if the machine that arrives is not what was specified or if they change it later on.

 

[Rob.]

possibly changing a lot of SY final connections as every one I saw went into a plastic gland

Seen this done loads of times. I presume you mean a plastic compression gland?

I don't mind so long as, the braiding has been taken through the gland, is sleeved and is terminated properly to an earth terminal. 

 

[binky]

see lots of unearthed braids on SY - seems popular just to chop it off! 

 

[kerching]

Seen this done loads of times. I presume you mean a plastic compression gland?

I don't mind so long as, the braiding has been taken through the gland, is sleeved and is terminated properly to an earth terminal. 

Plastic glands

in this case they had used 3 core SY for the phases and the braid for the earth.....into a dodgy bit of connector strip that fell,off when I touched it.....this was possibly because there were no screws in it

 

[binky]

is it legal to use braid for earth? I don't think the outer clear sheath is proper rated for 240v?

 

[Andy™]

is it legal to use braid for earth? I don't think the outer clear sheath is proper rated for 240v?

braid is just that, a braid. its not designed to take a fault current or be used as a cpc. its copper equivilent will also be very low

 

[Rob.]

is it legal to use braid for earth? I don't think the outer clear sheath is proper rated for 240v?

The braid is only a screen, it must be earthed at one end minimum, but is no use as a CPC.

Not to mention that SY isn't a recognised installation cable in BS7671, unless it's changed with the new edition. So using it should be noted as a departure on the EIC.

 

[kerching]

using it should be noted as a departure on the EIC.

EIC.....that could be a long wait :innocent

i got paid

i left the MD a business card

we shall see

 

[binky]

The braid is only a screen, it must be earthed at one end minimum, but is no use as a CPC.

Not to mention that SY isn't a recognised installation cable in BS7671, unless it's changed with the new edition. So using it should be noted as a departure on the EIC.

 I always thought the braid was for 'light' abrasion resistance only, but it still needs earthing as an extranuos conductive part.  To me, it's for connection machinery in an industrial facility where damage is unlikely but possible. Given taht getting 5 core SY is usually quite easy, there is no excuse for usig the braid as a CPC.

Never understood why it isn't recognised? 

 

[Rob.]

SY cable is built to the German VDE standard, which isn't recognised elsewhere in Europe, so it can't be part of 7671. 

The braiding can only be classed as a screen as because it can't be proved to handle fault current. So it does not comply using it as mechanical protection. 

Of course it does offer it some physical protection, just not in the eyes of the regs. 

Also the outer sheath reacts quite badly to UV light, an doesn't take long before becoming opaque, brittle and then falling off if left in the sun. Then water gets in an corrodes the braiding. 

 

[Evans Electric]

It seems to handle oil immersion etc   and is nice & flexible  .    Not that easy to find the current carrying capacities  of it .    I have them in the PC  somewhere thanks to Sidewinder .    Must check that out .  

 

[Sidney]

Even when buried in duct SY outer sheath is susceptible to water ingress causing the steel braid to rust. It used to be used a lot in telecoms until this compliance issue raised its head, brilliant stuff when used inside for connecting kit up.

But I've seen the effects of UV and water submersion on it, I wish I'd have grabbed some photos.

 

[Evans Electric]

Anyone notice that the Germans also use  what is basically  a SWA  without the SWA  for connecting various motors , say , within a machine  or printing press. Just a flexible , multi core , fairly tough , oil resistant .   

Some  30 yrs ago our then NICEIC man for this area  brought a short piece of German cable to show us ,  he thought it may be the future ,  basically a version of Hi-Tuf  if anyone remembers it .    

A black, multi core  with a supple inner sheath  & a very hard , tough  outer sheath .   He was thinking of light industrial & commercial applications  and SWA being overkill .

I agreed ,  we used it for a while but I don't see it around anymore . 

Yep  just Googled it , sill there .   Ideal for outside work on domestic I'd think . 

 

[Rob.]

It's a right b!tch to strip though. 

Imagine cold swa, well  it's worse than that on a good day.

 

[phil d]

It's a right b!tch to strip though. 

Imagine cold swa, well  it's worse than that on a good day.





2

Isn't that the same stuff they used down the mines, we see a lot of that where I live because we had a lot of pits in the area and a lot of people got cable from work to do jobs at home. I remember my mate buying a house and the previous owner was a pit man, he'd done loads of electrical work and it was all done in that cable, even extra lights were wired in 2.5, why? Because it was free of course.