Cable sizing

[nero]

Can anyone help me out with sizing two cable please? I dont have access to any of my reg's.

Cable is in a duct,
210 meters long,
3phase machines @ 225KW and a 3phase machine @ 500KW.

Cheers

 

[Knobhead]

Look at volt drop, current and de-rating tables, if we just give you the answer you’re never going learn to play “big ball”.

The size of loads your talking about are in the “major league”.

 

[nero]

I know how to work out the calculation , I just dont have my 17th edition or the Irish ET101 or Amtech on this laptop to work out the CCC, cable size, Cg or Ca.

If someone could check their tables for the info I will work out the cable size and check the volt drop is acceptable.

 

[nero]

Can anyone provide the above info so I can work out the cable size please?

Cheers

 

[Sparky Ninja]

well if you know how to work it out you will also know we cannot work it out without the data to apply the correction factors.

 

[Knobhead]

Being the pessimistic / sceptic that I am, I think your wanting your homework done for you.
PS I’ve looked at you’re previous posts.

 

[nero]

Homework in the middle of August?????? Pessimistic alright.

The cable is 210meters long.
Installed in Duct underground.
Cable is single core PVC Aluminum
3cables max installed in duct for working out grouping factor.

First Machine has an Ib of 562.5A and I’m proposing a In of 600A
Second Machine has a Ib of 1250A and I’m proposing a In of 1300A

If someone can provide the following from the tables I can work out the calculation please. CCC, cable size, Cg and Ca

Im away from home and have no access to my Regs to check the tables.

 

[Sparky Ninja]

what about Cc?

would you like a guess for Ca?

 

[nero]

Cc? If you mean CCC Current Carrying Capacity of the cable I have asked for it in previous post.

If you had the exact Ca for a ground ambient temperature of 35Degrees please

Cheers

 

[Sparky Ninja]

Cc is currently a factor to be applied for weather the over current protection device used is a BS 3036 (becomes Cf in amendment 1). Cc also applies if the reference method is a cable buried in the ground (which seems relevant in your scenario if you are referring to an underground duct).

 

[oxocube]

The cable is 210meters long.
Installed in Duct underground.
Cable is single core PVC Aluminum
3cables max installed in duct for working out grouping factor.

I can't imagine how 'single core PVC Aluminum' would be suitable. Did you mean single core AWA aluminium?

 

[nero]

OK, Cool. As the saying goes you learn something new every day. CC is not something we have covered in the ET101 2008 the most up to date Regs in Ireland. But the calculation I’m trying to work out is for a UK installation so what you have described would be relevant.

When was amendment 1 implemented as I done the 17[SUP]th [/SUP]ED back in 2008 or 9 I think. I haven’t detailed the spec to type of protective device other than its total “In”

 

[nero]

Its definitely single core XLPE PVC Aluminum, we have used it on existing turbines. I can email you the cable spec if you need. I couldn’t figure out how to insert a snap shot of the spec sheet

 

[Sparky Ninja]

OK, Cool. As the saying goes you learn something new every day. CC is not something we have covered in the ET101 2008 the most up to date Regs in Ireland. But the calculation I’m trying to work out is for a UK installation so what you have described would be relevant.

When was amendment 1 implemented as I done the 17[SUP]th [/SUP]ED back in 2008 or 9 I think. I haven’t detailed the spec to type of protective device other than its total “In”

Amendment 1 was introduced in July and is enforced from the 1st January 2012.

 

[piscopatos]

for 3phase machine @ 225KW
Cable: 2((3x240+120)sqmm NYY + 120 sq mm NYY)

for 3phase machine @ 500KW
Cable: 4((3x240+120)sqmm NYY + 120 sq mm NYY)