It's well-known that GFCI outlets can cause issues for powerline networking. However, is this true even if the powerline adapter is plugged in upstream of the GFCI outlet (i.e., on the same circuit, but between the panel and the GFCI outlet)? It seems to me that in this case the GFCI outlet should have no effect, but I can't find any explicit statements to this regard.
I'm planning to put a new circuit in that would be set up like this (panel => outlet for powerline adapter in basement => GFCI outlet for outdoor lights), but I want to make sure I won't regret it later. I can put in two separate circuits if need be, but since they would run in exactly the same location, that seems like a waste.
Best Answer
Power line network adapters will have at least two plug in module units. There may be more if you are having additional network drop points.
If there is any truth to the rumor that a GFCI could be a problem for a power line network adapter it would be if the adapter had to send its RF signalling through the GFCI unit between two of the adapters. Therefore the particular concern, if one indeed exists, would be that all of the power line network adapters would need to be situated on the same side of the GFCI. So:
You do have the somewhat unrelated issue that sometimes if power line network adapters have to bridge from one of the 120VAC phases to another 120VAC phase there will be attenuated signal due to poor coupling between the phases. Suppliers do sell capacitor coupling units that can be installed in the main breaker panel to supposedly solve this problem, however even this issue has to be taken with some grain of salt.