Sorry for the "late" post. Been busy.
Here's the deal with "qualified" people. This is what OSHA would call a "performance oriented" standard. Which means that it is important that the unique hazards of each workplace be used to determine the correct method of compliance.
So, "Reno" is correct with his short and to the point answer, the concept of qualified is technically determined by the employer. However, they must verify the compentency of the employees that they consider to be "qualified." The training must meet the very general requirements of 29 CFR 1910.332(b). http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9909#1910.332(b)
So... what does that mean? Well, basically, OSHA will look at NFPA 70E as guidance. But, technically 70E is not a "law" so, if an employer has come up with a training and information program that can be demonstrated to be the equivilant of this consensus standard, then OSHA is likely to accept it. For example, has the person been through a recognized apprenticeship program. Or, are they licensed in the state where they are working as a "qualified" person? Those may also be used as potential evidence that the person is "qualified."
Although it doesn't add much in the way of "new" information, here is a link to an OSHA letter of interpretation on this question: http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=21262
OSHA has even applied the concept of a "qualified" person to the resetting of a circuit breaker! http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=24009
Which brings us to second part of "reno's" comment:
the equipment manufacturer will typically train the customer's people
Just because a person is "qualified" doesn't make them "competent" to work on all equipment. Too often persons that might otherwise be "qualified" get in over their heads working on equipment that they have not been trained to service. This happens way too often, particularly with facilities maintenance staff.
I could go on longer, but, I don't want to get off track here. If you need additional clarification, give us another post.