Shielded cable help please.

[Oldmanandhistoy]

Hi All,

A friend of mine recently gave me some 4 core shielded cable; he does not recall where he got it so I can not email the supplier.

Each core is 0.75mm sq annealed copper and 24/0.2mm.

My question is how much current can I put through it at around 50Vdc? Also does the current rating change with Volts rating and if yes how would I calculate it?

Thanks for any help given as always it is very much appreciated,

John

[widgitmaster]

http://www.action-electronics.com/

This is a good source for multi-conductor shielded cables!

[Oldmanandhistoy]

Originally Posted by widgitmaster http://www.action-electronics.com/ This is a good source for multi-conductor shielded cables!

Thanks for the reply Widgitmaster.

Unfortunately it does not help me as I live in the UK, already have the cable and does not tell me the rating of my cable but thanks for the response anyway.

John

[Al_The_Man]

That looks like it is somewhere between 19 & 20swg (18&19AWG) which according to the N.A. code for industrial machinery puts it around 7amps, the british standard may differ a bit. The voltage will make no difference to the current rating, but the wire insulation usually has a max. voltage rating.
Al.

[Oldmanandhistoy]

Thank you very much Al_The_Man; where would we be without you?

John

[Oldmanandhistoy]

You don’t need to answer that one.

John

[epineh]

Here is a handy conversion for AWG to mm

http://www.engineeringtoolbox.com/aw...uge-d_731.html

and Al is spot on with the current, I make 7.5 amps, the voltage might be stamped on the cable, and doesn't directly relate to current carrying capacity, so long as it can insulate to the voltage level. High strand count also helps with conductivity for the same given cross sectional area, due to the "skinning" effect of electron flow, but I think you will be safe with 7 amps.

Russell.

[Oldmanandhistoy]

Originally Posted by epineh Here is a handy conversion for AWG to mm http://www.engineeringtoolbox.com/aw...uge-d_731.html and Al is spot on with the current, I make 7.5 amps, the voltage might be stamped on the cable, and doesn't directly relate to current carrying capacity, so long as it can insulate to the voltage level. High strand count also helps with conductivity for the same given cross sectional area, due to the "skinning" effect of electron flow, but I think you will be safe with 7 amps. Russell.

Thanks epineh

[Greolt]

Rusell

I looked at that site that wigetmaster gave a link to.

Wish it was in Aus. Shipping is the killer.

Do you know where in Aus we can get shielded cable without paying for a roll ?

Greg

[epineh]

Not really but it is on my to find out list, I will let you know. I ended up buying some through my work for my router, 15metres of 6 core 0.5mm for about $50.00 bucks.

I will have a look around and get back to you.

Russell.

[Oldmanandhistoy]

This may seem like a daft question to you electronics guys but I need to check to be sure.

I have 4 core cable rated @ 6Amps and want to know can I use two with paired cores for 8Amps? Is the current shared between the two cores equally, so 4Amps each?
I am almost sure it is ok but just want to check to give me peace of mind.


Thanks for any help offered,

John

[epineh]

Its a bit of a yes and no answer from me, yes you can parallel the cable but take a little care, keep your lengths the same, I think for a stepper you should be fine, its not exactly supply distribution we are talking, and even then cables are paralled with certain conditions, namely the lengths are kept as close to even as humanly possible, the reason is that uneven lengths will have uneven distribution of load due to different cable resistance.

But I think you will be OK in this case.

8 amps... exactly how big a motor are we talking ?

Russell.