Volt drop cable calculator

[Scott89]

Hi guys I was having trouble working out volt drop. Type in google (Doncaster cable calculator) only a guide not exact but though it may help!

 

[Robson689]

It's not really hard, the longer you rely on websites to do it for you, the less inclined you will be to learn it! If you keep going over it, and make loads of practice questions you will remember it no problem

 

[telectrix]

itr's just 3 numbers multiplied together (that's timsed for the youngsters) and divvied by 1000. what's hard about that?

 

[Scott89]

Ok could you tell me what that is please ie the 3 numbers X together ?

 

[monkeyelectric]

Ok could you tell me what that is please ie the 3 numbers X together ?

Have you a regs book?

 

[Scott89]

(Mv/a/m) X design current then divide by 1000
I just don't understand what mv/a/m. Is

 

[Des 56]

Ok could you tell me what that is please ie the 3 numbers X together

then you posted

(Mv/a/m) X design current then divide by 1000

Next try please Scott

 

[Robson689]

(Mv/a/m) X design current then divide by 1000
I just don't understand what mv/a/m. Is

millivolts per amp per metre

 

[moose]

Length x Design Current x (Mv/a/m) x Factor(1.20) then Divide by 1000 Trada

 

[Scott89]

Thanks robson appreciate the helpful advice
My next question is how do I find my millvolts per amp per meter?

 

[monkeyelectric]

(Mv/a/m) X design current then divide by 1000
I just don't understand what mv/a/m. Is

Judging by you previous posts you are working as an electrician so how the hell do you not know how to do that fundamental simple sum and what it means? How do you work out volt drop in your circuit design?

 

[Scott89]

I used a website that does it if you look at top off page I'm not looking to be judged just looking for help so I can understand more. So if you have nothing helpful to say and your just looking to make me look little please don't post answer

 

[monkeyelectric]

I used a website that does it if you look at top off page I'm not looking to be judged just looking for help so I can understand more. So if you have nothing helpful to say and your just looking to make me look little please don't post answer

I'm not saying it to make you look little but don't you think if you're working as an electrician you should know how to work out volt drop without having to use a website? The tables are in the regs for various types of cable so look in there and post an example of how you would work it out without the use of a website

 

[telectrix]

look under volt drop in the osg. magic tables will give you the mV/A/m of all the cables you are likely to use.

 

[HandySparks]

Length x Design Current x (Mv/a/m) x Factor(1.20) then Divide by 1000 Trada

Where does this "Factor(1.20)" come from, moose?

 

[Stroppy]

Learn it as "milliVolts per amp per metre" rather than "em-vee ay-em" and it will make more sense. Div by 1000 because you want the anwer in Volts, not milliVolts.

 

[telectrix]

Where does this "Factor(1.20)" come from, moose?

the 1.2 factor is to allow for resistance variation with temperature. the tabled values are at 20dg.C so the actual figure at operating temp. will be higher.

 

[Silly Sausage]

The values in the tables are for the cables running at their maximum operating temperature.
You don't need this 1.2 factor for Volt drop calcs.
You can reduce the voltage drop for cables operating at lower temps by using the equation in App 4, 6.1

 

[telectrix]

The values in the tables are for the cables running at their maximum operating temperature.
You don't need this 1.2 factor for Volt drop calcs.
You can reduce the voltage drop for cables operating at lower temps by using the equation in App 4, 6.1

i stand corrected. was thinking of th resistance tables. you are correct in saying that the tabled values are @70deg.