May he use any voltage regulator from the pedestal, to his surge protector and finally to the coach without adverse effects? He wishes to get some brand of a 30 amp voltage regulator, here in Mazatlan, failing that, to order one.
I am not an expert or an authority - I just know these things are available and I use one - adverse effects I can't say. The ISB units are available pretty much all over Mexico - if you take the info I posted in both Spanish and English and show it to them they should be able to order it - ISB has distributors all over so it might only take a day or less to get on. I think all an RV needs is the 4000 but I am not an authority on that either.