In Washington State, if you are paying an electrician to install an EVSE like the Tesla Wall Charger, you should not pay State tax. Please refer to RCW 82.08.816 to check for yourselves. I called the Department of Revenue for Washington State today to confirm this. They agreed I should not have paid tax for my HPWC installation. They told me to give my electrician this BUYERS’ RETAIL SALES TAX EXEMPTION CERTIFICATE form. In that form at the top fill in the details about your electrician, then check box 2b, then at the bottom check Individual, fill in your name and address, and sign. That's it. My electrician agreed to refund me the tax. Couple of other interesting things: The Tesla shop also charged me tax for the HPWC so I filled in another form and sent it to [email protected]. Will update this thread with their reply. If you look at the RCW, or you look in the form under box 2a, it seems the batteries inside electrical vehicles are also tax exempt. Very interesting, should investigate this further.