volt drop calc

lockhes · Jul 29, 2011

is this right

mv on chosen cable from regs x length of cable run x design current of circuit

divided by 1000

is it calulated amps or the breaer your going to use

is that all as im trying to work out for this lighting circuit but to get the volt drop under 3% the cable needs to be 6mm

ta for help

JUD · Aug 5, 2011

Spoon242 said:
Nice one,

32 metres is my last point on the ring and thats my 26A and then divide by 4 because its a ring , ie 4 off 2.5 mm cables.

So ((18 ÷ 1000) x 26A x 32M) ÷ 4 = 3.74v

Do you mean the ring is 32m from end to end or it's 32m to the mid-point. If it's the latter then your ring circuit length is 64m.

The length of the ring starts and finishes at the CU.

Spoon242 · Aug 5, 2011

JUD said:
it's 32m to the mid-point. If it's the latter then your ring circuit length is 64m.

QUOTE]

Im getting there Jud, yep 64M

Thank you for helping me understand, you are making it nice and clear for me.