Trip free, IIRC, means that the circuit breaker cannot be held in the "on"
position during an overcurrent condition. In other words, you can't hold the
switch on with your hand or with a clip if it is trying to trip. The circuit
breakers we use on our marine engines are required to be "trip free, manually
reset types" by the US Coast Guard. In addition, they are required to meet
the SAE or UL requirements for "ignition protection," which means
(simplified) that when surrounded by a flammable gaseous mixture, they will
not ignite that mixture by any sparks that might be generated during the
operation of the device. The breakers in the picture look suspiciously like
common marine circuit breakers.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

 
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