*Voltage drop Question Calculation help*

[kathleenbilly]

Hello guys looking in,

Just want to make sure i'm doing this right as i'm still a bit fresh,

This is the senerio as follows,

Single lighting circuit from a 230v supply on a 10 Amp MCB.

1.5mm PVC Singles total length from board to furthest point 40 metres.

1500 total watts of various lamps being used in 6/8 rooms and corridor area.


Is the calculation as follow,

Size of cable x the Amps being used x the distance of the cable, devide by 1000 to give the volts

I'm not not sure about the rest basically is the voltage drop of the above within 17th edition is it 3 per cent i'm reading 6.9v in my on site guide ?

Any clarification appreciated on getting me right on this, thank KB

 

[montybaber]

Its actually mv/a/m of the cable multiplyed by design current multiplyed by length of run in m divided by 1000

 

[kathleenbilly]

OK Looking at my on-site guide and the information i have above the voltage drop per amp per metre for 1.5mm is 29 (page 130 table 6d2)

So using my info listed above would i do

29 x 6.52 x 40 / 1000 = 7.56 v

if this is right i'm only allowed 6.9 v

so my voltage drop is too much??

 

[kathleenbilly]

Hang on is it,

29 x 40 / 1000 = 1.16v ?

so i'm well within ?

I think i was right the first time looking at the guide again can any one just confirm that for me, thanks KB

 

[JUD]

Hang on is it,

29 x 40 / 1000 = 1.16v ?

so i'm well within ?

I think i was right the first time looking at the guide again can any one just confirm that for me, thanks KB

No. You were right the first time.

29 x 6.52 x 40 / 1000 = 7.56V (3.29%)

You would need to use 2.5mm2