The traverse relative permeability of steel wires depends on the particular sample of steel. The used value is an average value for wires of diameter from 4 to 6 mm.

We consider round and flat wires touching if they cover more than 95% of the mean circumference. which is calculated separately for the two armour layers

Symbol
$\mu_{\mathrm{t}}$
Unit
-
Formulae
$10$touching wires
$1$wires not touching
Used in
$H_{\mathrm{3}}$
$H_{\mathrm{3_{\mathrm{2}}}}$