Recent updates to NEC Code 555 require Marina owners to consider ground fault protection at both the individual slips and at the power distribution center feeding the separate branches to each slip’s power pedestal. Typical power feeds now require relays that can handle conductors carrying more than 300 amps necessitating the solution to involve additional components.
To address this problem, NK design engineers developed a relay with an aperture measuring four inches in diameter allowing conductors (carrying 800 amps or more) to easily pass through the relay. These large aperture AG-LC relays can be used to monitor the main feeding circuit to the pedestals and to energize a shunt trip breaker protecting the entire docking facility. Additionally, the smaller aperture NK Technologies AG Series relays can be used to monitor individual power pedestals at each slip, with the relay output energizing a shunt trip breaker circuit at the pedestal.