well from what I know if all the lights or other things in the house dimmed when the compressor kicked on(thats the part inside the the ac unit) and if the line that the ac was on overloaded it would kickout the breaker and then no ac..
also you cant run a high current appilance on a long extension cord as the current drop would make the unit barely run.. Thats why the frige and window ac units have a short cord.. and your problem is probably to light of wiring in your condo... and all condos IHO are made from the cheapest supplies they can get... I would call someone to inspect your wiring... as you have a problem.. And I would guess that he would say that - the loft is probably the longest distance from your breaker box and they used the wrong gauge wiring as hardly anyone puts a ac unit in a loft...
