Can a CT interfere with solar power line communications?

[HenryH]

I have a solar panel system that sends power down as 240 V AC. It also sends info from the microinverters on the roof to a box in my house using power line communications (PLC) on the same wires. I have CTs on the solar wires to monitor the solar output. Can the CTs cause data losses on the PLC? I have been having a lot of errors lately.

This is a theoretical question. I will try removing the CTs and see if the errors go away, but I would like to know if this is theoretically possible so that I have confidence that I am not just being superstitious.

[djwakelee]

I’m going to say no.  The CTs in use here are somewhat designed to work best for low frequency 50/60 Hz.  Your microinverters (Enphase or otherwise) speak on the power line in the 100-200MHz band.

I have all kinds of CT clamps on my setup.  32 Emporia circuit clamps, Emporia mains clamps, Enphase consumption clamps, Enphase production clamps, The-Energy-Detective consumption and solar clamps.  I don’t monitor the solar for microinverter comms errors, but during setup everything was in the green.  I also have legacy X10 devices in my home, and those operate in the same general frequency as the solar comms – but seem to coexist without issue.

I would more suspect a noisy device in your home.  Not audible noise, but electrical noise.  A cheap CCFL or LED bulb for example, or a poorly designed AC/DC power brick.  Have anything new like that in your home?

[movax]

CTs are passive devices; they shouldn’t induce anything into the lines you are monitoring. If the errors started happening after you installed the CTs, chances are a wire may have been jostled loose / moved around in such a way that you’re seeing these errors.

[Author]

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