Resistance per Meter for copper cable (R1+R2)
Hmm, looks like I've opened up a can of worms here !
Here's the full example question and the the bits I've got to.
Consumer unit, 190V A.C., with BS3036 fuse, Ze=0.49Ohms
45m PVC Armoured cable, clipped directly to wall with 5 other circuits
50 Degree C ambient temp, 9Kw load
Cable runs through 100mm Insulation
IB = 9*103/190 = 47.36Amps
In = 60A (From Page 195 Fig3.2A Next biggest to 47A)
Correction Factors
1). Cf - A BS3036 device 0.725
2). Cg - From Table 4A1, (Page 210) Method 1 used
From Table 4B1, 1+5=6 Circuits, Bunched = 0.57
3). Ca - From Table 4C2 50°C, Armoured PVC = 0.87
4). Ci - From Table 52A, page 97 100mm = 0.81
Iz = 60 = 206Amps
(0.725*0.57*0.87*0.81)
From Table 4D4A, Armoured PVC, Method 1, Single Phase, 222A nearest
70mm2 csa conductor
Then the problem, table 9A O/S/G only goes upto 50mm
Table 9A (Page 158) of the O/S/G gives mO per meter values to
calculate R1 + R2
R1+R2 = mO/m * Length (m) * Temperature multiplier (Table 9C)
1000
So I'm a bit confused as to who's right.
Leigh
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