ARMOURED CABLE SELECTION

Dear guest,

This is not serious issue to discuss in engineers level. However I will tell you how to calculate it...First find out the current by using the formula. select the cable from the chart...you will get chart from any cable manufactures catalogue,...then using the data of length and voltage drop details from the cable chart, calculate the voltage drop...select the proper size cable to limit the voltage drop in allowable range.....since you have find this website and asked a question, i do not think that it is difficult to find the answer yourself.

Hi Mr. Alanvaderi,

If possible can you explain with example like cable selection , voltage drop cal. etc please.

hanu

send me your email...in reply i will send you the detail

Hi Alanvaderi,

Thanks for your great helping, my Mail Id : b_hanuma@yahoo.com

Hanu

Pl.send the voltage drop, selection criteria for armured cable selection to my mail sd61@rediffmail.com also.

dhayanandhan.s

Dear Mr. Alavanderi,

You have suggested to Mr. Bethini Hanuamnthu to provide his mail Id. so that you can forward the data.

He informed that he is yet to receieve the details through mail from you.

Please provide the details to me also, my Id. is sd610@rediffmail.com

DHAYANANDHAN.S

see the post #12. This is what I send to hanumandh and you. But your mail bounced back.

You can use 35 sqmm copper cable, and the voltage drop will be 7.3%

Guest,

A 7.3% voltage drop is often too much. I would suggest sizing the cable to limit the voltage drop to less than 5%. That would mean choosing a cable with cores of 50 sq.mm. or larger. Remember, that many supply systems can have the voltage droop or decrease when their load increases, so keeping your voltage drop less will increase the tolerance you have for power supply voltage problems.

--JMM

→ British Standard 7671 again.

If you're asking this question, you shouldn't be carrying out this installation, as you do not sound qualified to do so. You're asking one question, how many others have you over looked. Get a qualified person to do the job, before you endanger somebody. This will allow you to sleep better at night (causing injury to somebody due to your ignorance, should cause you many a sleepless night?).

12kW on 415V, 3 phase supply will give at pf=0.8, a current of ~21A . Take it 25A

As suggested to you before by previous, there are cable selection table that give the cable cross section for the required amps.

Then you have to check on the same tables, the required derating for the length and voltage drop. Therefore, you will have to select a bigger cable to derate to your 25A.

as, also suggested, a 35mm2, 3 or 4 cores (Neutral?) armoured cable might be OK and normally will give ~ 3% drop on the distance. BUT CHECK THE CABEL MAKER TABLES BEFORE TAKING my SUGGESTION SERIOUSLY!

Knowing what amperage you will be handling is a start. There are tables which will tell you that. The second issue is how is it armoured? For instance, you must not lay in too much wire in most conduits because the wires need some air space around them to keep cool. But the most common armoured cable is likely BX cable. This link is to the alcan site which makes armoured wire. Scroll down to page ten.

Dear Alanvaderi,

Excellant Explanation.

Thanks for great help

Regards

Hanu

Dear Alavanderi,

Thanks for your valuable inputs. Can you share the Cable chart for my refrence ? or pls give me the link so that I can look into it.

Thanks

--

Tushki