M
markc17
ok.. so any help appreciated..i want to add some Klik lighting management boxes to the end of a circuit to control 10 lights. The circuit up to the ceiling rose I wish to utilise to feed my first klik is wired in conduit using 2.5mm cable. I want to add a two way lighting switch to control the boxes, using 1.5 mm 3c & E cable rather than splash out 200 quid on 2.5 fp or the like... spanning a corridor 20 m long, so 40 if I go there and back on the strappers. The circuit is backed up by a 10 amp breaker. I have done some calcs and was wondering if somebody could look them over and see if I am correct.. its the different sizes of cable that is confusing me slightly:This is what I’m thinking to work this out.. please help if im way of the mark..
A- Closest leg (classroom 1) 2.5 m in conduit 22m from CU – 9 x 40w – 360 – 1.5 a
B – Next classroom 2.5 mm in conduit 32m from CU– 9 x 40w – 360 – 1.5 a
C – Furthest ceiling rose, including 40m strappers (there and back) in 1.5 mm 77m from CU – 10 x 40w – 1.7 a
So section c = 29(tabulated) x 45(distance between b & C) x 1.5a = 1.96 drop
B = 18 (tabulated) x 10 (distance between a & B) x 1.5a = 0.27
A = 18 x 22(distance to first point from CU) x 1.5a = 0.56
0.56 + 0.27 + 1.96 = 2.79 total volt drop using both sizes of cables
So I can use 1.5mm 3c and e to join my boxes, and do my switching.. even though it is at the end of the circuit.
A- Closest leg (classroom 1) 2.5 m in conduit 22m from CU – 9 x 40w – 360 – 1.5 a
B – Next classroom 2.5 mm in conduit 32m from CU– 9 x 40w – 360 – 1.5 a
C – Furthest ceiling rose, including 40m strappers (there and back) in 1.5 mm 77m from CU – 10 x 40w – 1.7 a
So section c = 29(tabulated) x 45(distance between b & C) x 1.5a = 1.96 drop
B = 18 (tabulated) x 10 (distance between a & B) x 1.5a = 0.27
A = 18 x 22(distance to first point from CU) x 1.5a = 0.56
0.56 + 0.27 + 1.96 = 2.79 total volt drop using both sizes of cables
So I can use 1.5mm 3c and e to join my boxes, and do my switching.. even though it is at the end of the circuit.