SY flex

[One_of_them]

Guys,

I'll be honest ive never had much chance to work with this stuff.

Been asked to run a 32A 3-phase supply for some IT equipment. Looking around it appears somebody has been in previously and ran a similar setup in SY flex 10mm I think. They have used normal glands into the board but I aint opened it up to see if the braid has been terminated. Last time I saw this stuff used was on a production line and the braid was just trimmed off and tapped over.
I know about the correct glands to use but other than this is there anything that I may need to be aware of. Its only a short run to so would have thought 6mm would suffice?

cheers

 

[telectrix]

6mm should suffice. and you know to use the correct glands. what about hi-integrity earthing for IT equipment, though.

 

[One_of_them]

from what they mentioned it appears to be a small cabinet (servers im guessing) as oppose to computers. Does the high integrity still come into it as I cant see anything in the book. Again from my quick look I dont see a returning earth on the current setup as it's been done as a radial.

 

[telectrix]

the high integrity earthing should be on the supply to the computres, so not your concern, IMO.

 

[Darkwood]

If the server bank is expected to exceed 10mA leakage to earth then it would be wise to run it in 10mm S/Y to comply with 543.7.1.3 (red regs... no' may have changed in green but not got it to hand), if you lack the info about leakage current then i would edge on caution and do it 10mm S/Y utilising the 10mm earth core as well as the braiding using appropriate glands.
Your description is a little hazy as to exactly what this cabinet is going to be for but im on the assumption your supply cable will power a bank of socket outlets thus its your responsibilty to either work out leakage current or allow for the fact it could exceed 10mA if the panel is added to.

 

[telectrix]

it's 3 phase though.

 

[Darkwood]

it's 3 phase though.

Missed that..Tel ... must be tired, but with that in mind then a 4core and earth s/y, again without knowing what the supply is actually doing advice is a shot in the dark, could be multiple balanced socket outlets but with the regs no' etc quoted and the previous been in 10mm then OP has something to go on now.

 

[telectrix]

agreed^^^. have to be reasonably well balanced across phases as well to minimise the neutral current.

 

[Darkwood]

Should be ok as the cables been upsized to 10mm from a 6mm to keep to 543.7.1.3 (iii) if this is the one of a few methods he can do and as hes only been requested to supply 1 x 32amp 3ph supply for it so assumably the design is such that N loading is already taken into account.

 

[One_of_them]

true gents

thanks

 

[Moses]

from what they mentioned it appears to be a small cabinet (servers im guessing) as oppose to computers. Does the high integrity still come into it as I cant see anything in the book. Again from my quick look I dont see a returning earth on the current setup as it's been done as a radial.

You say its a short run, how many meters is this short run?

So what are servers, coffee machines?

Servers are Computers with lots of hard drives, Hi watt PSUs, Mulit-processor Motherboards, lots of fans etc.

You will need hi-integrity earthing.

 

[AdieB]

Are you sure it is for IT equipment and not a 3-phase UPS (uninterupted power supply) I have carried out computer room installations before and all IT kit I have seen is single phase. But another thing is to check your insurance as most do not cover for work in computer rooms or on computer server towers or cabinets. I had to go through many companys to obtain cover. I have heared that a local company to me cut through the fibre optic supply cable causing the servers and the infrastructure to crash. The company tried to get £500,000 for loss of buisness. It was only that the installation company had informed them that they were working in the area and that their terms and conditions state that any loss is limited to £1000 that they got away with it, but were thrown off site and had to pay the repair cost of another company. Sorry to put a downer on this post but its not always that simple with IT installations.

 

[One_of_them]

You say its a short run, how many meters is this short run?

So what are servers, coffee machines?

Servers are Computers with lots of hard drives, Hi watt PSUs, Mulit-processor Motherboards, lots of fans etc.

You will need hi-integrity earthing.

Run is about 4 mtrs
I dont like coffee
Thanks

Are you sure it is for IT equipment and not a 3-phase UPS (uninterupted power supply) I have carried out computer room installations before and all IT kit I have seen is single phase. But another thing is to check your insurance as most do not cover for work in computer rooms or on computer server towers or cabinets. I had to go through many companys to obtain cover. I have heared that a local company to me cut through the fibre optic supply cable causing the servers and the infrastructure to crash. The company tried to get £500,000 for loss of buisness. It was only that the installation company had informed them that they were working in the area and that their terms and conditions state that any loss is limited to £1000 that they got away with it, but were thrown off site and had to pay the repair cost of another company. Sorry to put a downer on this post but its not always that simple with IT installations.

defo not a UPS

From a further check/chat today, it appears this new supply is to feed what I can only describe as a 3 phase extension lead, that will fix to the cabinet and then what ever is in the cabinet will plug into this extension lead. This lead is powered by the 3 phase supply but the plugs are just normal 13A type

 

[Bobster]

Just to throw it out there.

I'm only allowed to use SY for control wiring on the sites I look after. Reason being , on their website it states it's not for use with mains voltage.

SY Control Flexible Cable BS6500, VDE0250

 

[polo1]

Not all SY is control cable - regularly used on 230v.:wink5: