result of the class 3 current voltage and volt amp limitations provided on the outputs of the multi output power supplies the installation and use of the lighting units can be done with a freedom and flexibility far superior to that which otherwise would be permissible in particular the class 3 classification permits the use of lighter and more flexible wires than are required in conventional installations and implies that the cables connecting between the power supplies and the lighting units do not need to be conduited or armored moreover subject power limited lighting system permits the use of convenient light weight plug in connect cords between the output receptacles on the multi output power supplies and the input receptacles on the lighting units in an expectedly typical situation subject power limited lighting system would be installed as follows first a number of multi output power supplies would be permanently installed in suitable spaced apart locations on the permanent ceiling which permanent installation would probably be done by electricians third lighting units or fixtures would be placed at suitable locations in the grid probably by the same persons that installed the grid structure fourth each lighting unit would then be plug in.