How do AHJs know which mark or service provides compliance with the NEC?

For structures taller than sixty feet, the extreme wind loading applies to the structure and all the supported facilities. Lets crank through an example calculation.

An electrical inspector or any user of electrical equipment must be confident that the product meets the requirements of the standard.

Electrical inspectors have a significant responsibility in the approval process and the testing labs, which are featured in this issue, provide a mechanism to assist in that process.

Fifty years ago, pinsetter machines, or bowling machines, was a mechanical marvel, easy to operate, quick to repair, and built to last. What happens when you have to inspect an old one?