Hello @jlpsd ,

Welcome to our community.

Since you already own the TL-WPA7517 KIT, it's strongly recommended to add the same series of powerline devices (TL-WPA75xx series) to your network. Using different series of powerline devices in one network might result in performance degradation.

You can add additional TL-WPA7517 units or similar TL-WPA75xx models to expand your network. The good news is that TL-WPAxxxx models (like your TL-WPA7517) can act as both adapters/transmitters and extenders/receivers, so you have flexibility in how you set them up.
 

Passthrough Plugs:

There are Wi-Fi powerline adapters with passthrough plugs available. To find specific models with passthrough functionality and WiFi capability, please visit: Powerline
You can use the filters on that page to find products that meet your specific requirements.

Mixing Ethernet and Wi-Fi Powerline Adapters:
You can use Ethernet-only powerline adapters (TL-PAxxxx models) together with Wi-Fi powerline adapters (TL-WPAxxxx models) in the same network. It's best to stick with the same series (TL-PA/WPA75xx) for optimal performance.

To pair additional devices to your existing network, simply press the "pair" button on each device and wait for the "Home/Powerline" light to become solid (this usually takes 1-2 minutes).