Supply Cable Size and correct socket ratings!

[dasrik]

Hi Guys,

In our place we have several machines that are fed from 63A sockets. The supply cable to the machines is CY and currently
6mm has been used which is no good for 63A

But the 63A sockets are fed by a 32A breaker.

Is it ok to use the 6mm as the socket is fed by a lower rated breaker?

I'm a bit unsure on this one, on one hand if the supply is ok and fed at 32A it should be ok BUT what if someone plugs the machine into a socket that is fed at 63A (if we have any - need to check) this would be well outside the regs - from memory i think we would need 16A cable for 63A

If this is in the regs can you point me in the right direction.

Cheers

 

[netblindpaul]

7671 stops at the 63A socket outlet TBH.
The machine is a fixed load, as long as that load is no more than the cable can take then you will be fine.
However, I often see SY badly or incorrectly terminated at these plugs.
The "flex" is protected by the 32A anyway.

 

[dasrik]

By badly terminated, do you mean like this?

One i found the other day, the machine had lost a phase and i found this in the plug. You can't see on the photo
but there was only 2 strands holding the wire in. & the neutral was about to fall out as well.
At least it wasn't the earth... this time!

 

[malcolmsanford]

Think that is YY cable you have there but certainly not SY

That is SY

Ha ha just realised the picture may not show the relevant part of the cable, if that is so apologies and foot in mouth springs to mind

 

[dasrik]

it CY - Just found this pic of all three

 

[malcolmsanford]

Lol thanks Dasrik, I can take the foot out now then mate.

 

[dasrik]

lol

I'm glad i found that picture of all 3 - couldn't for the life of me think what YY was!

 

[malcolmsanford]

Only reason I mention it mate was years ago I designed some circuits for a machine shop and the connections from the conduit drops to the motors I wanted to use Kopex conduit for the environment and protection, but for some reason I wrote Flexicon, so when it arrived the guys fitted it, I came around blew my top saying that they were trying to pull a fast one on us, only to be presented with my spec ................ouch !!!!

Luckily the lad doing it saw the funny side and we did a deal and he changed it for a few alterations that suited him ............but since them I make double sure what is there is what I asked for lol .

Just hate to think you order up a load of SY and only wanted YY

 

[netblindpaul]

One thing CY does not always have an opaque outer sheath.
The C in CY is for Copper, the S in SY is for Steel.

 

[dasrik]

Oh right,

I was under the impression we used CY because of the grey outer sheath, with the opaque sheath you can see
the sheath rusting which they don't like in a food factory!

Just out of interest why would you use steel instead of copper? or vise versa? apart from cost

 

[Inteificio]

copper provides a better magnetic screen, steel mechanical protection.

If you have problems with EMI, then go CY, if you have an issue with staff chewing sy

 

[netblindpaul]

CY can't rust as it is copper!
Only SY will rust.
However IF correctly terminated the ends should be sufficiently sealed to prevent ingress of any fluids as rusting could be the least of your worries.