Doug Miller wrote:
Sorry, can't agree. The OP was asking, essentially, if a 15A breaker
and a 30A breaker are the same thing. It is obvious that they are not.
Hence it's a dumb question.

In the end, yes. But I can see where someone might think a double breaker
with a single handle that has "30" written on it is composed of two 15A
breakers, not two 30A breakers. It's wrong but it wasn't pulled out of
thin air; there is a logic to the wrongness. So not all that dumb a
question.

Here's a distantly related question. Is it ever permissible to use a two
pole breaker for two 120V circuits not for 240/208? Let's say someone
wanted to ensure that when circuit is turned off or tripped the other is
off as well. Maybe for some equipment that for whatever reason has two
120V feeds and you wish to enforce that it's completely dead.