Against the flight crew's wishes an A320 Mechanic attempted to install an extension cord from an aircraft AC power outlet to power a passenger nebulizer but failed because reliable power could not be obtained.

Narrative

Arrived at aircraft and maintenance was installing a temporary TR unit in last seat of aircraft to power a passenger nebulizer. Using an extension cord; maintenance ran the cord from aft power outlet by door 2L to the TR unit. Maintenance could not get 120v from outlet though aircraft fully ground powered. Both pilots and flight attendants knew that these outlets do not provide adequate power. A Flight Attendant remarked that they are instructed in training NEVER to use them. The Flight Attendant also remarked that in the Flight Attendant Operating Manual; Nebulizers are NOT an approved device. The Maintenance tech said he was told by his Super that they are approved. The Captain said he only knows of battery-powered Nebulizers being observed previously. My concern was of in-flight fire hazard because of the inconsistent voltage known to come from many of these outlets; and the 400hz cycles that I'm fairly certain harm sensitive electronics that are used to 60hz household power. Problem solved itself because maintenance could not come up with needed voltage on our aircraft after testing numerous outlets onboard aircraft. They removed item and wiring from aircraft. We were told that this nebulizer was for an outbound passenger the following morning. This report being filed in the spirit of safety and inter-departmental issues that were presented.