So, I have been looking for a schematic of a 2-pole (240v) GFCI circuit breaker/device. I found one on the Siemens' website and it looks like the neutral/grounded conductor is only used as a part of the detection and not interrupted when the device is "tripped". The reason I ask is:
A colleague found an exterior spa that was connected via liquidtight flex to a 240 volt double-pole circuit breaker (ok, the breaker was not just hanging there, but was installed in a listed panel - you knew what I meant). A double-pole GFCI circuit breaker is present in the service equipment to protect the entire circuit, but the breaker closest to the spa is a standard double-pole breaker. His question was whether or not the neutral needed to be a part of this disconnect. The answer seems to be very similar to the clarification in this thread: viewtopic.php?f=3&t=729&p=1956&hilit=gfci#p1956
[2013 CEC] 404.2(B) essentially states that you shall not disconnect the grounded conductor unless (exception) all conductors are disconnected simultaneously. 430.105 says pretty much the same thing.
The Siemens schematic looks like the neutral is not interrupted as a part of the "trip" function. Unfortunately, I do not know the brand of circuit breaker and I have not found any other breaker schematics, only methods of wiring.
The way I see it is the present setup for the spa is acceptable, unless the (non-GFCI) breaker is not approved/rated to be used as a means of disconnect.