Zigbee devices and PLC network

Hi All,

I have a Devolo DLAN 1200+ PLC network in my home where the majority of the devices are Wifi AC APs, and recently I started to notice a HUGE reduction in the speeds that the adapters connect at from the devolo cockpit interface.

Out of pure curiosity I started to disconnect the Wooley “Basic” SWITCH-ZR03-1 (Claim to be eWeLink in the HA Manufacturer column) devices and I noticed a significant effect. I have 3 of these in the house and only installed them onto small lamps yesterday which is why they were the first place I looked.

The adapter that’s typically the slowest in the PLC network (it’s connected to a different RCD circuit to the one with router access and at the furthest point from the breaker in a ring) goes from ~110-150Mbps, all the way down to ~40-80Mbps when I plug in all the devices with these smart relays

This is repeatable too. If I flick the switch to disconnect the Zigbee relay from power, the average connection speed goes up, if I switch it on… it goes down.

I also have some Wooley SA-030 (Claim to be Sonoff in the HA Manufacturer column) devices, and whether these also have an impact is inconclusive, but I dont think they do. Similarly I have a few devices that use the TS0011F and I didn’t notice any impact from disconnecting these.

I have a variety of lighting control devices, mostly the Sonoff ZBMini, but flicking off the entire lighting circuit breakers off doesn’t seem to have any affect.

Of course it’s hard to analyse PLC circuits given the connection speeds fluctuate constantly, but I’m almost certain these little “basic” zigbee relays are having a negative influence.

I have tried putting the device on a surge protected power strip, purely as a punt to see if it made a differece and if it did, it was negligable. I also tried plugging the devices into a power strip that was fed from the adapter to see if the noise was filtered, that also doesnt seem to be the case.

Has anyone had any experience with this or any ideas what I can test to mitigate?

Edit - Is this more likely to do with poor quality power regulation in the device rather than something more directly “zigbee” related?

Did you ever get to the root cause for this?
I have a similar issue but can’t easily prove yet.
I have the 2 devolo 1200 plc’s and one 1200+ Wi-Fi
The devolo have worked for years with minimal issue.
I also have Innr and ikea smart plugs which also have work fine for years.
Recently I purchased some zigbee smart plugs from Aliexpress (link) which joined my zigbee network and work as expected.

But recently my devolo power line network has been very flaky. The 1200+ wifi constantly drops out of the network and needs a power cycle to rejoin.
Then today the power line network collapsed and none of the devices could connect.
I’ve had this once or twice before and in the past powering down all devices then powering on and re-pairing has fixed it.
But today after hours of power cycling and trying to pair none of the devices would join…
Then I powered off the Aliexpress smart plugs and straight away the 1200 plcs joined and have been solid ever since. For some reason the 1200+ Wi-Fi still won’t join though so not sure if it’s faulty or if something else is causing the issue…

It has me baffled at the moment.