Is a Generator with Bonded Neutral Code Compliant?

Generator Grounding Requirements

A generator with a bonded neutral is considered to be in compliance with NEC Article 702, which outlines the requirements for grounding and bonding. Bonding the neutral of a generator to the frame ensures that any fault current will follow the path of least resistance to the ground, reducing the risk of electrical shock. According to the NEC, the neutral-to-ground bond is required to be no larger than 25 square millimeters (3.9 mils) in size.

NEC Compliance for Bonded Neutral Generators

NEC Article 250 outlines the requirements for grounding and bonding of generators. According to this article, the neutral of a generator is required to be bonded to the frame, and the bonding conductor is required to be sized based on the ampacity of the generator. For example, a 10-kilowatt generator with a 20-ampere rating would require a 10-ampere bonding conductor, per NEC Table 250.122. Additionally, the NEC requires that the generator be installed with a grounding electrode system, such as a ground rod or a grounding plate, to provide a safe path for fault currents.

Grounding and Bonding Best Practices

While a bonded neutral generator is generally compliant with NEC requirements, it’s essential to follow best practices for grounding and bonding to ensure safe operation. This includes proper sizing of the bonding conductor, correct installation of the grounding electrode system, and regular inspection and maintenance of the generator and its grounding system. Additionally, generators should be installed with a 30-ampere circuit breaker or fuse to provide protection against overcurrent in the event of a fault. Regular inspections and maintenance can help identify potential issues and ensure safe operation of the generator and its grounding system.