Power Surges vs 12v adapters...what happened? HELP?

I will make sure I do that. Yea it was pretty bad, but this is the reason I paid for the "protection". Better the replaceable adapters then the Cat. :) The 5th wheel could be replaced through Insurance, but not the cat and other replaceable items. I suggest to anyone to pay for the added insurance just in case.

crazyred75 wrote:
12V adapters that I am referring to are the items such has a XM Radio and a Neck Massage device that had removable adapters/chargers. They were plugged into a surge protector. Other hardwired items such as speakers, or the toaster were fine.
Maybe I am not explaining it properly, but I read what was on the back of the adapter.

Thanks, presumably these are plugged into 120vac and not 12vdc. Anything plugged into 12vdc shouldn't be affected.

My XM radio operates on 6vdc and has adapters to plug into 12vdc or 120vac.

What you had damaged are what many people refer to as 'wall warts' which convert 120vac to whatever power is needed for the appliance. I think correctly they are a 'power supply'.

To avoid this issue in the future I would suggest that anything capable of operating on 12vdc be connected to 12vdc. The converter/battery then provides some protection from damage.

Like many have said, you probably experienced an open ground allowing 240v to be supplied to your 120v items.

12V adapters that I am referring to are the items such has a XM Radio and a Neck Massage device that had removable adapters/chargers. They were plugged into a surge protector. Other hardwired items such as speakers, or the toaster were fine.
Maybe I am not explaining it properly, but I read what was on the back of the adapter.

The above referenced RV Electrical nails the topic. The imbedded article regards open neutral beautifully described why a high voltage occurrence can happen even with the additional protection available to rvers for 50 amp service. My take away message is for one who moves frequently, using the 30 amp service is preferred if the rv usage is low enough to support. Load testing may be useful for semipermanent installations but it would slow down the set up/takedown time for a traveler.
His other topics are very informative.

pops

Could you describe exactly what you mean by "12v adapter"? Everything I use that operates on 12v gets plugged directly into the 12v system. The 120v items get plugged into the 120v system.

Last summer I had my Progressive SSP50 plugged into the 50 amp plug and my motor home plugged into that. I experienced a brown out in the middle of the night. This happened several times finally ending with no power coming into the motor home. The next morning I was able to see the 50 amp plug was fried, the surge protector was fried, and the prongs on my cord showed discoloration. Luckily, nothing inside seemed to have been harmed. All systems worked on batteries and when I switched to the 30 amp plug everything worked as usual. We left the park, with no replacement or even much of an apology and only discovered several days later that our Splendide Combo was dead. It has it's own built in surge protector and that was fried as well as the motherboard. This was almost a $1000 lesson adding a new plug, new surge protector, and WD repair. I replaced the surge protector immediately. Oddly enough, this had been a Christmas present and I had just started using it on a regular basis. 6 years without one with no problems, 6 months with one and it saved my coach ...go figure.

There is a lot of good information on this web site: RV Electric

Look at the section called "open Neutral" and it explains how an open neutral can cause high voltage to the coach.

This thread is great information, and scary as hell...

I also realized that the electrical devices that had hardwired 12v plugs such as the speakers, Bissell hand vacuum and toaster, were fine. It was just the 12v adapters that were removable that fried.
It is defiantly a learning experience.
Thanks again all for your input!

Yea. It would be really hard to figure out what the exact dynamics were. It could be the trencher cut the neutral, and or ground wires first. Or at least before the hot legs were severed. And some how a higher than normal voltage was injected into the coach. Also and arc flash can create huge spikes to be on the line.

Surge protectors generally work by shunting the spike to the ground wire. If the ground wire was cut, it couldn't do that.

And apparently it wasn't quite fast enough in shutting the power down. It needed to decide to drop the relay and then the relay needs time to physically open and break the connection. It is VERY quick, but in this instance just not quick enough to save everything. On powering up the coach it can take it's time analyzing the power before engaging.

Bottom line - the 12 volt adapters probably have some small diodes or something that was more sensitive and burned up quicker than the EMS responded. My best guess is some of the spike voltage got through because it was more than the shunt device could handle, or there was no place to shunt it too remaining. The cutting of the cable, most likely made this a worst case scenario.