The Blue Sea Systems 9077 is a three-pole AC rotary selector switch rated 65A, UL listed to 600V AC, for choosing between two 120/240V sources.
This selects between two AC sources, typically shore power and a generator, with a positive Off position between them. That Off position is essential. Switching directly between two live sources would connect them together momentarily, which is exactly what a source selector exists to prevent.
Three poles switch both current-carrying lines and the neutral, giving full isolation on a 120/240V system rather than leaving the neutral common between sources. A common neutral between shore and generator is a fault path that will not show up until something goes wrong.
It is a selector rather than a breaker, so over-current protection still has to appear upstream or downstream in the design. The industrial-rated rotary mechanism works cleanly with one hand, and the compact body fits relatively thin panels where protection is handled elsewhere. Explore more marine electrical switches.
- Selects between shore and generator with a positive Off
- Switching live to live would briefly connect both sources
- Three poles isolate the neutral as well as the lines
- A selector, not a breaker: protection still required
