The outdoor lights have sensors built into the fixtures. The bulbs that came with the fixture is a CFL (Compact FLourescent). I assume therefore that these should work OK without interference, and they have until recently. So that doesn't really correlate.
I agree that if the product was sold with a CFL it should work without excessive noise. It's possible that your CFL's were designed to work with photoelectric sensors or the sensor itself has a modified output stage. That does not mean that they don't interfere with X10.
As far as the system working previously - you've made changes. What was working before may not work now. I'm not sure what type of circuit the CFL manufacturers use to excite the bulb, but you can be sure it's low cost and probably subject to drift (both thermal and over life). Since these lights are on when your problems exhibit themselves, I'd consider disabling them as a test.
I scoped my neutral compared to ground and there is considerable interference (>200mV) on the neutral at least on one phase. It doesn't however interfere at all with X10 controller operation so I'm not sure if my interference pattern is normal, has always been present or what the source is.
When you say you're using a
"Scope", are you referring to an oscilloscope or a X10 troubleshooting tool (ELK ES-M1)?
I'm also confused by the statement that you are checking between
"neutral and ground". This may have been a simple typo on your part - if so ignore the following (I'm not trying to be insulting).
Your switches operate between supply (black) and neutral (white). Ground is used for safety (grounding fixtures, appliance chassis, etc) but your switches really aren't referenced to it. Your ground line should not be carrying current unless you have a fault in the electrical system. The neutral line is carrying all of the return current from all of the devices in your house (yes it will be noisy VS ground).
If you are actually using an oscilloscope, you would need to monitor noise between supply and neutral. Please don't attempt to measure across the 120V line unless you know exactly what you're doing (in which case you shouldn't be reading this anyway).
With the AC running I see the same thing. I can see the X10 signals clearly on one neutral (one unfiltered wall plug) but not on others (with GFI). The lamps that are on X10 are not GFCI circuits and they all work. I have not scoped another circuit that corresponds to 'different phase' since the house is single split phase 220VAC incoming. Home wiring, not commercial. So I don't see correlation.
I have however looked for other X10 type signals during daytime hours and saw none other than mine.
- A split phase 220V system has two 110V (hot black) phases (90o apart) and a single neutral (white common). 220V is generated when you bridge across both hot phases (110 + 110). When you bridge from a single Hot phase to neutral you get 110V.
- X10 signals are sent over the Hot side of your wiring system (black). This is why you need a coupler to bridge the two phases of your electrical panel.
- If you were actually using an oscilloscope to monitor X10 activity between neutral and ground I wouldn't expect you to see much (if any) signal other than on the actual circuit sending the information. Again - your monitoring the wrong side of the system. The signals are on the hot side. You can only see them on the neutral side because of line resistance and distributed inductance.
- I have many X10 modules on GFI circuits with no problems (as do other members of the forum). I do not have experience with the new Arc fault interrupter.
- You've looked for extraneous X10 signals during daytime hours (signals from outside your house). Unfortunately you need to look at the exact moment that your neighbor goes to the bathroom and activates his motion sensor. Don't assume that the signals don't exist just because you can't see them at that moment. If the signals are from outside your house, changing housecodes should at least change the problem.
Please don't take any of the above as a slap in the face. You may understand all of the above and were testing from neutral to ground because it was safe and convenient.
When troubleshooting problems like these you often need to think of multiple, additive problem sources. I've added CFL's (more noise), a new AC unit (better coupling between phases?), the noise frequency of my outdoor CFL's has shifted (sum = invalid X10 reception).