Which insulation color is allowed for a current-carrying roottop dc conductor on a functionally grounded 6kw PV system?

An installer is hired to troubleshoot a 10-year-old roottop system with open-circuitvoltage of 300V. The ground-fault detection (GFD) device has tripped. The insulation on the exposed source circuit cables has deterlorated with multiple cracks and has no flexibility. Which concern is the MOST likely safely issue when servicing this array?

An installer is working on a 1000V DC PV array. What is the minimum PPE required per NFPA 70E for arc flash protection?

A worker is installing modules on a roof 20 feet above grade. What OSHA fall protection is required?

Insulation resistance testing is being performed on the conductors of a 3-year-old PV system. With a constant high test voltage being applied to a dc conductor, the test results in a high resistance reading. Which does this finding indicate?