It has been suggested by at least one moderator on this site that EPA Section 608, which restricts who can purchase and handle refrigerant, including who can connect a set of manifold gauges to a unit, applies only to CFC and HCFC refrigerants (class I and II refrigerants).
Can someone please clarify if it is legal or illegal for a homeowner without an EPA license to attach his own manifold gauges to his own equipment if it is charged with an HFC such as 410a?
From reading sections of the statute (not just the EPA summary) it is my understanding that effective November 15, 1995, Section 608 applies not only to CFC and HCFC refrigerants, but also their "substitutes." [The EPA has separately stated the term "substitutes" is not meant to restrict the sale of refrigerants that do not contain Ozone Depleting Compounds, such as 410a. Federal Register/ Vol. 70, No. 70 / Wednesday, April 13, 2005 / Rules and Regulations / ENVIRONMENTAL PROTECTION AGENCY /40 CFR Part 82 [FRL–7899–3]. ]
Best answer from the EPA website: http://www.epa.gov/ozone/title6/phaseout/technicians_contractors_faq.html
Is EPA technician certification required to service R-410A systems?
No, at this time EPA technician certification (i.e., EPA Section 608 certification) is not required in order to service R-410A systems or other stationary refrigeration and air conditioning systems containing HFCs.
It appears this activity is legal, provided the 410a is not intentionally released into the atmosphere. +100 to Tyler for being first and closest to this answer.