I've been using a Hugh's Autoformer for 12 years now. First one was 30 amp which I used up until I bought my current coach, which uses 50 amp service. So, I sold my 30 amp and bought a 50 amp Autoformer. I have a lot of sensitive electronics in my coach and I would not tempt fate by connecting without it. I have had ZERO electrical problems in my coaches through the years.