250-45 to double insulation

Whether to ground or not to ground-that is the question. The rules for the grounding of electrical equipment are found in Article 250 of the National Electrical Code¹. The rules in Article 250 have changed over the years to unfold a studied plan² for equipment grounding. The plan is continued under the aegis of the Panel 5 Code Committee. The stages of implementation of the plan are reflected in changes in the prime safety standards concerning electrical equipment: UL 45, Standard for Safety for Portable Electric Tools³, for example, has been modified many times to implement the guidelines provided by the Code. Knowledge of the two methods of protection against electric shock-grounding and double insulation-covered in UL 45 should provide some insight to the level of protection afforded by each.