Do powerline adaptors need to be plugged into outlets that are on the same leg

Question

I used a powerline adapter like this to connect my security camera receiver to my router. This allows me to access the cameras from my cell phone which was working but now it doesn't. There's two things that may have caused this. 1. The receiver was unplugged for a while which may have affected the settings on the receiver. 2. The other powerline adapter was moved to a different circuit.

The settings on the security camera receiver look fine although it's possible the ip address changed and the phone may need to be re-connected.

I know the easy answer here is just plug the powerline adapter back into the old outlet. Unfortunately that outlet was removed because it wasn't code compliant.

Edit: Photos of the panel showing the which circuits the powerline adapters were/are now plugged in to.

Answer 1

I did the unthinkable, and started to read the manual for the product you linked, and in the troubleshooting section there is a theme:

Try another wall socket and make sure all powerline devices are on the same electrical circuit.

If you search the PDF for "circuit" you find this phrase several times. I didn't find where the manual lists using the same phase or circuit as a hard requirement, but you can infer from the troubleshooting that they fully expect you to use the same circuit, which I think is a "dumbed down" way of saying it should be the same phase/leg.

I also found this in their FAQ section:

Q3.5: Can Powerline adapters work if they are separated by different electric circuits?

A: No. If they can pair in the same room, but the powerline LED turns off when you move one powerline device to another area, this usually means they are plugged into separate electrical circuits, preventing them from communicating. Please try different locations.

I think they are being a little concervative, because I do have powerline adapters on different breakers, and they work reliably.

Netgear is more optimistic, which muddies the waters a bit because most of these devices are based on the same protocols and theorys:

Can powerline be used in homes across multiple phases?

Yes, but you will either suffer a noticeable loss in performance, or if the signal is too low the units will not be able to communicate.

Finally the Homeplug (standard the devices use) wiki page states:

One of the greatest technical challenges was finding a way to reduce sensitivity to the electrical noise present on power lines. HomePlug solved this problem by increasing the communication carrier frequencies so that the signal is conveyed by the neutral conductor, which is common to all phases.

In conclusion, the answer appears to be a big "Maybe".

Answer 2

Cross-phase communication for power line carrier products can be a challenging problem. (see a white paper from Intellon, a manufacturer of PLC devices, there.) You may be able to improve the coupling between phases, at least for a short time, by turning on an electric-powered heating appliance such as a range, oven, clothes dryer, or water heater. If connectivity improves while one of those appliances is heating, that's an indicator that the two modules are not on the same phase.

If you conclude that the devices are not working well because they're on different phases, there are three things you could do to improve the situation:

1. Relocate one of the devices in hopes of randomly choosing an outlet on the same phase as the other device
2. Re-arrange circuit locations in the breaker panel so that the chosen outlets are on the same phase
3. Install a cross-phase coupling device (if you can find one).

The reason why a high-power heating appliance may temporarily improve the connection is that such an appliance can be thought of as basically a low-value resistor. The high frequency signals used in PLC can travel from the transmitting device through wiring to the breaker panel, out to the heating appliance on one phase, through heating element, return on the other phase, and from there out to the receiving device on that second phase. This path can have lower loss than other paths that might exist between the phases.

As was mentioned in comments, this is most commonly applicable in the US and other countries where multi-pole service is found in a residence. However, it's equally applicable anywhere multi-pole or multi-phase service is found: find some heating appliance that is powered between the poles/phases and turn it on to see whether it improves the PLC communication.

Answer 3

American residential power is usually two split-phase legs off a power pole mounted transformer with a center-tapped secondary winding. The center tap is connected to the house neutral. You'll get the best connection if your two powerline adapters are on the same circuit, but you have a good chance of them working even if they are not on the same circuit as long as they are on the same leg. And since there are only two legs in a normal house, you can probably find a workable outlet with a little bit of trial and error. Even better if you understand how breaker panels work, you can then try only outlets that you know are on the same leg.

What is unlikely to work is to have powerline adapters on different legs. This requires the signal to go through the power pole transformer and such transformers are not able to carry the frequency band required.

Answer 4

If you're still working on this, look at the circuit diagram on the top of the breaker panel. You can see that the old outlet is on the same power leg as the receiver, while the new outlet is not. I have shown this clearly in the attached image.

Answer 5

There are devices designed to allow this to work, and to not endanger you while you install it. (This one is just the first I found, there are probably cheaper ones.)

In the early days of powerline communications, they just suggested installing a small capacitor joining the two sides of the circuit. It must be able to take 240V, and to be small enough to pass the frequencies involved. Installing it is dangerous unless you are very careful.