I'm thinking of starting to use powerline networking for my pc, but I heard that if the outlet near my modem and the outlet near my pc are on different breakers, powerline networking won't work. How do I see if powerline networking will work for me? Thanks in advance.
It strongly depends on the age of your house, the brand of breakers, whether they are on opposite service legs, and whether they are straight magnetic breakers or AFCI or GFCI breakers, which is often determined by the age of your home and whether the equipment is in a bedroom or kitchen.
In particular some early AFCI breakers would block powerline networking.
My suggestion is to buy it and try it, and to return it or see if you can move a breaker if it doesn't work.
Best to check with manufacture, but yes your assumption is justified.
PLC technology for the most part is superimposed over just one side of the two poles that supply the panel.
To remedy this, a microfarad capacitor that matches the PLC's frequency can be connected in parallel to each phase, or pole , that supplies the panel. Usually, these are sold as bridges/boosters by the same company that sells the PLC technology. A common booster would plug into a 240 outlet or would be hardwired into the panel by a qualified electrician.
Other PLC technology may integrate RF ( radio frequency ) to compensate for the hurdles that PLC technology runs in to.
There is the try first and return later approach as others have suggested. Many stores don't have a problem with this but if you're like me time is a scarce commodity and would rather not have to deal with returning stuff if possible.