surge protection & voltage regulation

[kenandjudy]

I have read the threads on surge suppresors and autoformers, I plan on installing an autoformer on board the coach and was wondering do I also need a surge suppresor?

[bncinwv]

The Autoformer has limited surge suppression built in, but the ideal installation will have an Autoformer and an electrical monitoring system (EMS). The EMS provides protection from over-voltage, under-voltage, ground problems, etc. by disconnecting harmful currents (i.e., low voltage, high amperage) before they enter the rig and damage electrically sensitive devices. The Autoformer will boost voltage in low-voltage situations to prevent damage to the same electrically sensitive devices, however it typically can "boost" voltage by about 10%. If the voltage is very low, even the 10% "boost" will not bring the voltage up to non-damaging levels, hence if you have an EMS as well, it will shut the feed off in that situation. The same thing applies for over-voltage, the Autoformer will allow high voltage through, whereas the EMS system will not. Yes, both systems are on the expensive side, but the protection in "bad power" parks and areas is well worth it in my opinion. Many MOCers are currently using an EMS system from Progressive Industries including myself. I also have a Hughes Autoformer since I do camp in many older campgrounds which are apt to have power supply problems. Hope this helps and provides some clarity.
Bingo

[Art-n-Marge]

Some will install both. You don't need both but it's about the amount of protection in the event of a major surge.

If the surge is high enough it can actually damage a surge protector as it tries to protect your electronics and then may need to be replaced. This will be the least expensive than trying to replace all the electronics in your RV. While the Autoformer does have surge protection and if the surge is high enough to damage it, it would need to be replaced and is more expensive to replace than a standalone surge protector.

There have been stories of RVers (not just in MOC) praising they had both and that electrical surges have fried someone's surge protector but "saved" the Autoformer from the same fate. The Autoformer adds the extra protection if the voltage drops too low, which would cause the amperage to raise and this could cause damage to some electronics. But it is supposed to shut down if the voltage drops too low.

The trick is knowing how to wire this all into an RV that has the shore power, and generator capabilities automatic detection and isolation controls and what goes first (I think the surge protector gets connected to the power source, then the Autoformer connects to that and the other side of the Autoformer goes to the power distribution panel. There are plenty enough members that have done this and hopefully will comment.

[H. John Kohl]

I have a Autoformer that I have never used. I also have the EMS and It has tripped five times protecting me. I recommend the EMS first and Autoformer second in priority.

[bncinwv]

I have to agree with John that IF you have to choose between the two, go with the EMS!! We have used our Autoformer as well, but if you do not go to campgrounds or areas with inherent low-voltage problems, you could be better off with the EMS only. I will state that there are some campgrounds that you would not think would be problematic. For instance, our Autoformer has kicked in many times at the large commercial campgrounds at Myrtle Beach. I attribute this primarily to the large number of high-end rigs drawing 50 amp feeds. Out of curiosity, keep us informed as to what choice(s) you do end up making.
Bingo