Moving to Nevada as a master HVAC technician: every state's rule

Nevada does not issue a master HVAC or master refrigeration license, and no county or city was found to issue a master-level HVAC card (Clark County and Las Vegas recognize a 'mechanical qualified individual', which is simply the person who qualifies a contractor's C-21 license with the State Board). The state-level credential is a classification C-21 Refrigeration and Air-Conditioning Contracting license from the Nevada State Contractors Board (NSCB), issued to a sole proprietor, partnership, corporation or LLC and qualified by a named individual rather than held by the mechanic personally, with subclassifications for refrigeration (C-21a), air-conditioning (C-21b), sheet metal, maintenance, solar, chilled and hot water systems and industrial piping. An out-of-state master HVAC licensee who only wants to work for an employer needs no Nevada license at all (apart from the local journeyman card in Clark County and Las Vegas). To contract, the qualifying individual must show four years of experience as a journeyman, foreman, supervising employee or contractor within the past 15 years (NRS 624.260), pass the PSI-administered Nevada Business and Law exam and the C-21 trade exam within six months of filing (three attempts each), and the business must pay the $300 application fee and $600 biennial license fee, submit a financial statement, fingerprints and background check, and post a bond of $1,000 to $500,000 set by the Board, plus the Residential Recovery Fund assessment if it does residential work. Under licensure by endorsement (NAC 624.600 and 624.615) the C-21 trade exam and the experience certification are waived for a qualified individual who has held an active license with no discipline for the past four years in Arizona (CR-79 Air Conditioning and Refrigeration Including Solar, as the Board prints it), California (C-20 together with C-38), Connecticut (S-1 Unlimited Heating, Piping and Cooling), Louisiana (10 Mechanical Work statewide) or Tennessee (CMC Full Mechanical Contractor), documented with a License Verification Form from that state; the Business and Law exam is never waived, and no other state's chart contains an HVAC row. EPA Section 608 certification is a separate federal requirement for anyone who handles refrigerants.