I have found another source of X10 interference - one of my Juicebox Pro 40 EV chargers.
My Chevy Bolt is on a demand-based utility program with PG&E. This means the utility decides the best time to charge my car at night, when the grid load is lowest. The utility allow can decide how many watts/amps to allocate to charging depending on grid load.. I get compensated a little bit for that privilege (comes to about $80/year).
In practice, the charging usually starts around 2am, and typically the maximum amps that the car allows are used (32 amps).
I have noticed that while the car is charging, PLC signals from the CM11A located in my home office don't reach any distant X10 wall switches or modules located other rooms. As soon as I use the app on my phone or web interface to forcibly stop the EV charging manually, the X10 signals do reach the X10 modules/switches.
The Juicebox is charging at 32 amps / 240V. It's using a plug-in NEMA 14-50 (4 prong dryer plug).
I have two of those as I have two EVs. The other EV is a Chevy Volt which charges at 15 amps / 240V.
Either charger gets used with either car. Each Juicebox is on its own 40amp breaker as 25% upsizing is required for continuous loads. The breakers are off the main 200amp panel, not a subpanel.
Is there any X10 filter that can handle 240 amps / 32 amps continuous current ? Or am I SOL in this case ?