ISB Sola Basic Corrector de Voltaje

Basically, tie the two black neutral wires to a third, that goes to ISB neutral. Shore power white to 'intrada' white, and white from long cord to 'Salida'.

I am not entirely clear on what you are saying here. In US household wiring BLACK or RED is always your HOT wire - WHITE is always your NEUTRAL - GREEN or BARE wire is always GROUND. ALWAYS.

If you wire black to neutral you have reverse polarity.

I have had an ISB for several years and wired it myself but at this point I do not remember the internal wiring so not sure how they have it wired or which colors they use for what in Mexico - my thinking is electric color ID is universal/international.

On a standard 50 amp RV extension cord you should have one black, one red, one white, one green. The black and red are your two hots. On a 30 amp you should have one black, one white, one green. You only get one hot with 30 amp.

The US Navy trained me as an electronics technician and I have also wired several houses - new and remodel - and messed around with electricity most of my life. Please don't wire black to neutral.

Peterth who has posted on this thread is over near Ajijic - he used to be at Roca Azul - he is a good guy and if you PM him from this forum he may be able to show you how his ISB is wired. I think at least one other person at Roca has an ISB but not sure.

I have not observed it going into buck mode

I have never heard the term "buck" with regard to electricity. What exactly does this mean? Sounds like maybe it means the ISB will drop the voltage to a safe level if incoming exceeds 135 volts?

Anyone interested - you can buy an ISB Sola Basic almost anywhere in Mexico - but few places stock them so you have to order - ferreterias should know but if you take a copy of the info from the website they can probably order. They have distribution all over Mexico so they can be had almost anywhere in a day or two. All you really need in Mexico is the 4000 as you will rarely find higher amps available. A 4000 gives you 40 amp capability. If you want it to work for standard US 50 amp wiring you have to buy two of them - you won't need it in most areas of Mexico as you won't find 50 amp. Mine is not hard wired as I do not use it everywhere in the US - though I have found need for it in the US.