Master Electrician First Set 1-85 Questions With Complete Solutions

A 150 kVA service transformer has a 480Y/277 volt 3-phase primary and a 208Y/120 volt, 3-phase secondary. What is the approximate full-load ampere rating of the primary of the transformer? correct answer: 180 amperes Where a conductor is marked RHW-2 on the insulation what does the "-2" represent? correct answer: The conductor has a maximum operating temperate of 90 degrees C. For a grounded electrical system supplied by a feeder or branch circuit, the equipment grounding conductor shall be sized in accordance with _____. correct answer: the overcurrent protective device For lighting systems operating at 30-volts or less, the output circuits of the power supply are to be rated for NOT more than _____. correct answer: 25 amperes Using the standard method of calculation, what is the demand, in kW, on the ungrounded (line) service-entrance conductors of an apartment complex that has thirty-five (35) electric ranges rated at 11.5 kW each? correct answer: 50 kW Where a service riser is installed in a wet location and contains THWN insulated conductors, the wiring method used _____. correct answer: is permitted to be electrical metallic tubing (EMT) What is the MAXIMUM distance between supports for straight horizontal runs of trade size 1½ in. threaded rigid metal conduit