Quote:
Originally Posted by smac999
no they are not the same. they are intereconnected internally as well as externally. you can't just buy 2 singles and join the handles.
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The typical
marine circuit breakers such as Blue Sea devices have no internal interconnections. The
photo below is a similar desgin.
Common trip breakers
Three-pole common trip breaker for supplying a three-phase device. This breaker has a 2 A rating
When supplying a branch circuit with more than one live conductor, each live conductor must be protected by a breaker pole. To ensure that all live conductors are interrupted when any pole trips, a "common trip" breaker must be used. These may either contain two or three tripping mechanisms within one case, or for small breakers, may externally tie the poles together via their operating handles. Two-pole common trip breakers are common on 120/240-volt systems where 240 volt loads (including
major appliances or further distribution boards) span the two live wires. Three-pole common trip breakers are typically used to supply
three-phase electric power to large motors or further distribution boards.
Two- and four-pole breakers are used when there is a need to disconnect multiple phase AC, or to disconnect the neutral wire to ensure that no
current flows through the neutral wire from other loads connected to the same
network when workers may touch the wires during
maintenance. Separate circuit breakers must never be used for live and neutral, because if the neutral is disconnected while the live conductor stays connected, a dangerous condition arises: the circuit appears de-energized (appliances don't work), but wires remain live and some
RCDs may not trip if someone touches the live wire (because some RCDs need
power to trip). This is why only common trip breakers must be used when neutral wire switching is needed.