Need help understanding fuel permits

Hey everyone - so this is all new to me and the "www" hasn't been very clear from what I can find. So I'd appreciate any insights!

I drive a not-for-hire big rig (tractor only / no trailer) with 3 axles. It is not used commercially. It was recently brought to my attention that I need fuel permits because of the weight rating / axles. As a newbie here, I'm trying to understand how these work. Basically my questions are:

a) I live in PA and plan to do most of my driving within the state, occasionally crossing state lines to visit family and friends. Do I need fuel permit to even drive on the roads in PA?

b) If I cross state lines, do I need to purchase fuel permits for every single state I plan on driving through?

c) How do I go about getting fuel permits? Is there a central website or something?

Thanks everyone.

 

I built the world's only replica of Optimus Prime from Transformers. Just a custom truck I will tool around in...Hopefully bringing a smile or two on the highway along the way. So yes it's a personal vehicle and has been registered/insured that way

 

Www.facebook.com/Optimusishere

 

I do have the CDL class a. I already confirmed I don't need a dot number. What you mention about the 3 axle rule is what I have found as well. Have you see anything in writing with that exception you mentioned that it wouldnt apply to personal use vehicles? So far I havent