What is the Class 2 rating on a power supply?

A Class 2 power supply is defined by article 725.41 of the National Electrical Code (NEC codebook). Class 2 circuits consider safety from the standpoint of fire initiation and limit current to protect against electric shock. Class 2 allows a maximum output power of 100 Watts. Though NEC Article 725 is the guideline for Class 2, UL 1310 is the test standard for Class 2 units.