This is an incorrect use of powerline adapter. Not use extra power cord. Just plug it to wall powerline mount.

If you need extra only one adapter (with 1200 Mbps)not KIT just buy: https://www.tp-link.com/la/products/details/cat-18_TL-PA8010P.html

use tplink powerline adapters with wifi support You can use TL-WPA4220 Not KIT

According to your router, (If it has more then one port) try to give a different subnet to LAN port 2 and use 2 powerline with it. Also give different powerline network name. They will use same...

Try to look here: http://forum.tp-link.com/showthread.php?99770-TL-PA8010P-TL-PA8030P-v1-Connection-Problems

Mrjota wrote Hi there. I have the US version models, ¿Can I use those firmwares? Too many dropouts! Thanks You can use MVM file with only your US version PIB file. Dont use EU or UK version PIB. PIB...