In article , Chris Crinkle
writes

I have a 7 day timer, with a max load of 13A at 240V.
However reading the instructions its states there is an inductance
current of 3A. What does this mean ?

It means that the 13A rating applies only to purely resistive (heating)
loads.

An inductive load is something like a motor or an old style (inductive
ballast) fluorescent tube lamp and when a circuit containing something
like that it disconnected, voltages are generated that could cause
arcing across the opening switch contacts. The inductive rating is the
maximum current that can be switched on that kind of load without
severely limiting the life of the contacts due to arc wear or indeed
welding them together.

Similar restrictions apply to loads with large inrush currents such as
computer power supplies.
--
fred
it's a ba-na-na . . . .