[Elecraft] KPA500 - ground wire between the AC earth and RF output socket

[Johnny Siu]

Hello Group,
 
On page 19 of the KPA500 kit assembly instruction, there is a green ground wire connecting between the AC Earth terminal and the case of the RF output socket.  It is my first time to see such a ground wire design.  Is there any specific reason for doing that?
 
Thank for your advice in advance.

TNX & 73,


Johnny VR2XMC