Apple Computer Inc. uses the testing services of the Canadian Standards Association (CSA). The CSA is recognized by the Occupational Safety and Health Administration (OSHA) as a Nationally Recognized Testing Laboratory (NRTL).
OSHA created a set of standards for approving companies or agencies that do electrical and safety testing. These procedures for certifying a company as an NRTL mean that there can now be more then one source for testing. This allows vendors other than UL to be qualified as OSHA-recognized testing labs.
The insignia for CSA is on the PCI-based Power Macintosh computers, which shows that they are recognized by an NRTL. The /c means that they are also certified for Canada.
Additional information on OSHAs procedures is available on OSHAs web site at <
http://www.osha-slc.gov/>.