Originally Posted by Jopopsy
So YOU run: Post --> Cord --> Surge --> Autoformer --> EMS --> Cord --> Coach?
That's the way I would do it. Autoformers have their own surge/spike protection but, at best it is minimal. Replacing or repairing an autoformer is far more expensive than replacing a surge/spike arrestor so I makes good sense to put a sacrificial arrestor ahead of the autoformer.
The autoformer needs to be ahead of the EMS. Otherwise, the EMS would shut off the power before the autoformer would get a chance to boost low voltage. Since voltage can still goo too high or dip too low, even with an autoformer in the circuit, the EMS still needed for backup for over or under voltage protection.