When running horizontal 1-1/4 in, electrical metallic tubing (EMT) with compression fittings, what is the MAXIMUM permissible distance between condult supports?

A ground-mounted PV system operating with an open-critical voltage of 550V is in a public park. Which installation procedure will meet NEC requirements for protecting the public from potential electric shock?

A technician has been called to a scale due to a low-performing array. The technician will perform tests in the
24-source circuit combiner box. After putting on the correct PPE and turning off and performing lock.tagout of the inverted and combiner disconnect. Which is the next step to safely begin electrical testing in the combiner box?

An 8 AWG bare copper equipment ground conductor (EGC) is wire tied to the module mounting structure of a commercial rooftop solararray. After a few years of operation, some spots on the EGC begin to turn a green color and appear to be corroding more significantly that other places. What would the MOST likely cause of the problem?

An installer has decided to use 31 in. long. 3.1/2 in diameter conical ground screws as the footings for a
3.840W solar electric system. Access to he is too difficult to pour concrete footings. The soll is classified as sandy loam. The design wind speed is 90 mph with an uplift force of 32 ibs/ft2. What is the MINIMUM number of screw required to resist uplift loads?