According to IEC 60287-2-1 Ed.2.0 for a single group of cables and IEC 60287-2-2 Ed.1.0 for more than one group of cables.

Symbol
$inst_{\mathrm{air}}$
Unit
-
Related
$F_{\mathrm{m}}$
$K_{\mathrm{cv}}$
Choices
IdInstallationfactor Zfactor Efactor gInfo
11 single cable0.213.940.60Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.3 x D.
22 cables touching, horizontal0.292.350.50Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D.
32 cables spaced, horizontal (clearance >0.75 x D)0.213.940.60Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.3 x D, horizontal clearance ≥0.75 x D.
42 cables touching, vertical1.420.860.25Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.3 x D, horizontal clearance ≥0.75 x D.
52 cables spaced, vertical (clearance >D)0.752.800.30Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥1.0 x D,
63 cables touching, horizontal0.621.950.25Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D, vertical clearance ≥D.
73 cables spaced, horizontal (clearance >0.75 x D)0.213.940.60Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D.
83 cables touching, vertical1.610.420.20Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D, vertical clearance ≥D.
93 cables spaced, vertical (clearance >D)1.312.000.20Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D.
103 cables touching trefoil0.961.250.20Installation on non-continuous brackets, ladder supports or cleats, clearance to wall ≥0.5 x D.
111 single cable on wall1.690.630.25Clipped direct to a vertical wall. Cable or duct outer diameter De not greater than 0.08 m.
123 cables in trefoil on wall0.940.790.20Clipped direct to a vertical wall. Cable or duct outer diameter De not greater than 0.08 m.
13More than one group of cables0.961.250.20The arrangement of more than one group of cables is limited to configurations in IEC 60287-2-2
14More than one multi-core cable0.213.940.60The arrangement of more than one multi-core cable is limited to configurations in IEC 60287-2-2