Elevators and electrical devices are prohibited on Shabbos

Igros Moshe (OC II #95) It is prohibited to enter an elevator on Shabbos that an evil person entered into first. However if a goy enters first for his own needs it is technically permitted but is prohibited because of maris haaiyen. In addition it is prohibited because additional people that enter increase the work done by the motor. Furthermore if he is known as a G-d fearing person and surely as a talmid chachom use of the elevator is also a chillul haShem 

Igros Moshe (OC IV #64.1) It is prohibited to use electricity on Shabbos and Yom Tov even though  it doesn’t make a fire . Similarly a refrigerator or freezer is prohibited and obviously it is prohibited to turn on electric lights. 

Igros Moshe (OC V #18.27) It is prohibited to comb hair on Shabbos because it is impossible without pulling out hair. The Magen Avrahan says even according to the view that an inevitable action which is unwanted is permitted this is prohibited because you want to separate the hairs and it is impossible do do it without pulling out some hair. This Magen Avraham supports my view regarding the sparks produced when an electrical circuit is completed or disconnected with any electrical device. Similarly when increasing the load on an electric motor such as in an elevator. So even saying that the sparks serve no necessary purpose and you don’t want them however since it is impossible to obtain the use of electrical power for the elevator without them so the sparks are not considered an inevitable  side product but rather are viewed as an integral part of the elevator and are prohibited