Need to work out Volt Drop for your cable run?  Here is a useful Volt Drop Calculator you can try ... Or from the table below calculate by Amps x Meters x Volt Drop (from table) ie.  25M 6mm cable running 60V with 20A you would do 20A x 25M x 7.9 = 3950mV = 3.9V drop. So 60V - 3.9V = 56.1V

Cable sizes: Free Air cables can carry the following Amps (cables in conduit or insulated walls will reduce the Amps you can put through the cable).  The table below shows our recommended max amps to put though different cable sizes in Free Air and In Ducts, if in insulated walls you will need to reduce further.  The amount in brackets is the absolute max and must never be exceeded.