Hi Novice134,
We presume you mean a 2000W (or 2kW) radiator, which runs at 10A on maximum setting, rather than 2000kW which would be 10000A (or 10kA) which would be eye wateringly expensive to run.
A 10A load will be perfectly fine on a 13A extension, 3A of additional capacity above peak requirements is more than enough margin.
Answered by: Luceco Technical Team
Date published: 2022-03-14