Shore Power at Home Wired Wrong and Lightning also.

A direct or branch hit on an X transformer line (low voltage) is instant destruction for anything connected to the X lines.

A very nearby ground hit not only charges earth ground the EMP can and will fry electronics. Nearby meaning 33 meters.

Earlier on in a different thread I discussed "surge protectors" incorporating MOVS, Bi-directional TVS (Avalanche Diodes) and Plasma discharge tubes.

Lightning is frightening......a good phrase to remember.

Lightning operates by first establishing a pathway of ionized air. A feeder pulse instantly follows, then (perhaps) the main enchilada (there may be hundreds of ionization pathways established before a feeder and the big-one follows).

By incorporating a voltage sensitive surge protection circuit. All components in a surge protection circuit will die a violent death if a strike occurs. But enough time is purchased to allow ionization to choose the path of least resistance. Blowing first the TVS, then MOVS, then finally the gas tube discharge devices then continuing on to an earth ground pathway. All this happens in microseconds.

Would this protect downstream during a direct strike ? NO

How about during a branch strike? Perhaps infrequently but it would be unusual.

During a nearby direct earth strike? Most probably YES

For EMP pulse emissions? DEFINITELY YES

I have had similar configurations protect gen set distribution networks, and generator windings secondary rectifiers, and voltage regulator circuitry survived. I also used a .030" air gap tie from phase to earth ground but that's another protection circuit entirely.

When I get North señor Pianotuna gets an electronic MOV, TVS and GDT circuit housed in a hobby box, ready to connect. Hope the mail does not loose it :)

Ductape wrote:
If you're going to unplug in Florida every time there's a thunderstorm, might as well go ahead and get a big solar system and go off-grid entirely.

Does not apply to snowbirds, just the summer residents.

I am thinking more of a sacrificial Battery Minder to float the battery vs. unplug every time.

100w panel could well do the same. I recommend 100w solar for almost every RV regardless.

OP is talking storage at home so that is my perspective to unplug. Probably unrealistic while in use.

Progress report for those interested:

Plugged into shore power after all mods made to the subpanel to meet code, new transfer switch wired, and new chassis batteries.
All power works after resetting the two GFCIs. Inverter-charger works.
Started generator. Transfers power as designed.
Looks like I was lucky that I didn't get more damage.

Thanks to everyone for pitching in.

Ductape wrote:
If you're going to unplug in Florida every time there's a thunderstorm, might as well go ahead and get a big solar system and go off-grid entirely.

I was going to make that observation, but glad you did it.

MEXICOWANDERER wrote:
Lightning striking the earth or anywhere else near transmission or distribution lines can send inductive power up through the GROUND plug then dissipate through the neutral or phase connections. Total and complete disconnection from the grid would be the only reasonable protection against such an event. IOW unplug :)

This. And also you can get the same thru the neutral wire which is (supposed to be) grounded out on the street by the transformer.

You can also get hits thru your computer wireless setup which typically jumps from shielding in any antennas to core (via material permittivity). Best way to fix that is to not ground your computer equip.

If you're going to unplug in Florida every time there's a thunderstorm, might as well go ahead and get a big solar system and go off-grid entirely.

Does not apply to snowbirds, just the summer residents.

Unless you have a "reverse polarity bootleg ground" on that outlet, you can trust this:



Add in a meter to check for 120v, and you are good to go:



or

sealevel ram wrote:

ScottG wrote:
But regarding having a ground rod at the box, if you mean at the box where the 30A plug is then no, it should not have one. At the box the ground and neutral should be separate and grounding should only be achieved through the ground rod at the main breaker box.

Guess I was not clear in my original post. I installed a subpanel in the MH garage with three breakers, one of which is for the motorhome outlet.

Maybe but often times I just don't read so clearly. ;)

ScottG wrote:
But regarding having a ground rod at the box, if you mean at the box where the 30A plug is then no, it should not have one. At the box the ground and neutral should be separate and grounding should only be achieved through the ground rod at the main breaker box.

Guess I was not clear in my original post. I installed a subpanel in the MH garage with three breakers, one of which is for the motorhome outlet.

I don't think it would have made any difference either.
But regarding having a ground rod at the box, if you mean at the box where the 30A plug is then no, it should not have one. At the box the ground and neutral should be separate and grounding should only be achieved through the ground rod at the main breaker box.