From where are working space distances measured when dealing with enclosed live parts?

Working space distances for enclosed live parts are measured from the enclosure or opening. This is essential to ensure safety when performing electrical work. The enclosure serves as a barrier that protects individuals from exposing themselves directly to live parts, and the measurement is taken from the closest point of the enclosure or opening where a worker might access the equipment.

This consideration is vital in the National Electrical Code (NEC) to maintain safe working conditions and ensure that the required clearances are available for maintenance or emergency intervention.

While options such as the base of the equipment, the front face of the panel, or the sides of the equipment might seem relevant, they do not align with the NEC's specific guidelines for measuring working space around live parts. Measurement from the enclosure offers a more precise and safety-oriented approach, as it takes into account the actual physical barriers present, thus ensuring that proper distances are maintained for safe access and operation.