I want to add a word of praise for PI and the PT30C. I had a SG that died when we had our Class A and was informed that no repair parts were available for their 4 year old unit. Purchased a PI PT50C and was so happy with it that I purchased a PT30C when we bought our hotel room (Ar-One 15RB) on wheels. The PT30C worked great on the way home but refused to trip when hooked up at home in my 5 year old shop. Looked at the read out and it was showing 134 volts AC, a high voltage situation. The voltage was actually 124 AC according to 2 other meters. Contacted PI and explained the situation and they immediately sent me a new one and payed for the return shipping on the faulty unit. The reason it worked OK on the way home with the new trailer is the simple fact that most CGs are old and have voltages that run on the low side. I do remember the PI showing 127V at one CG on the way home. Buy an electrical management unit not just a surge guard.
Randy