Cable Sizing - Grundfos SQ Installation And Operating Instructions Manual

6.6 Cable sizing

Grundfos can supply submersible drop cables for
any type of installation.
The cross-section of the submersible drop
cable must be large enough to meet the
voltage requirements specified in section
5.1 General.
The table values below are calculated from the
following formula:
I x 2 x 100 x PF x L x ρ
q =
U x ΔU
Cross-section of submersible drop cable
q =
2
[mm ].
I = Rated maximum current of the motor [A].
PF = 1.0.
L = Length of submersible drop cable [m].
ρ = Specific resistance: 0.02 [Ωmm
U = Nominal voltage [V].
ΔU = Voltage drop [%] = 4 %.
The 4 % voltage drop is according to IEC 3-64, HD-
384 Series.
The calculation gives the following maximum cable
lengths at a supply voltage of 240 V:
Motor
I
N
(P2)
[kW] [A]
0.7 5.2
1.15 8.4
1.55 11.0
1.85 12
12
2
/m].
Maximum cable length [m]
2
2.1 mm /
2
1.5 mm
14 AWG
80 112
50 69
37 52
35 49
Cable size
2
3.3 mm /
2
2.5 mm
12 AWG
133 176
83 109
62 82
58 76
2 2
4 mm 6 mm
213 320
132 198
99 149
92 139