Most electric hook ups are protected by a 16A MCB (Miniature circuit breaker).
So you can grab 15A from this without tripping.
Without going to far into Ohms law, below is a few useful conversions.
(this is at 230v, but use it as rule of thumb for all campsites)
100Watts = 0.43Amps
500Watts = 2.17Amps
1000Watts = 4.34Amps
3000Watts = 13.04Amps
From the list above you can soon see that its OK to actually boil an electric kettle, even a fast boil 3kw one. Though I would not do that as you have to allow for your length of cable and volt drop and the kettle drawing more power to compensate for volt drop, but that's getting too technical.
I take a 750W microwave on camps where I have an electric hook-up = 3.2A
I also take a smaller electric kettle, about 2000w (or 2Kw if you prefer) = 8.6A
I have a small cooler running, about 100w = 0.43A
I also have 2x 11w lights running = 0.09A
Total load = 12.32A, so I don't even use my full 15Amps available.
This all said, I don't run the micro and kettle at the same time, just as a precaution.
Also it does pay to check you have a 15A supply, some sights might only give you a 6A MCB to prevent you plugging in a heater etc. Even with the 6A a 750w microwave is fine.
Look on the MCB where you plug your hook-up into and you should see it says something like B6 or B16 or C or D before the number, ignore the letter, its the number that matters.
Hope this helps a little, any questions please ask.
More information to follow on RCD's, Invertors and safety.











