What sort of configuration do you have to run the machines from a 220v outlet (like what type of three pronged connector)? Are you outside of the US since you say it is 13 amps? The 220v you commonly see in the US is usually 30 amp and for a large appliance like an air conditioner, washer, or dryer.
For my rigs, I run them with air cooling and three of them with the open case in my sig. This prevents any overheating with the cards OC'd. For power consumption, I mapped out the circuits in my place (by flipping the switches in the breaker box) and keep each circuit I'm using for mining under 80% load. So if it is a 15 amp circuit, I keep rigs drawing 12 amps combined and below on it.
This is to prevent a fire that could occur by maxxxing out a circuit which can't handle the 24/7 stress causing wires to melt or catch fire from the heat.
I use a Kill-a-Watt
meter to test how many amps the systems are drawing to get a good idea.
You might have to do something a bit different if you're in the UK or find a kill-a-watt that works there.
Also, if you can afford it, renters or homeowners insurance in case you really do burn the place down. Also you usually get covered for theft as well. Just make sure you have pictures of any machines serial numbers and what not.
One last thing I want to add. Your GPUs will throttle down once they hit a certain temperature to prevent damage, most of the time. If your cards are too close together inside your case, use a PCI extender
to split them up a bit more.