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Anyone had lightning strike your array and get saved by over current protection?

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mvonw

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Sep 23, 2019
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I was curious if anyone has firsthand experience with an ocpd actually protecting your inverter/home from a lightning strike?
I've had lightning strike a tree near me once and I can't believe a little electronic gizmo could dissipate and shunt that amount of energy....

I just installed them on my array (midnite solar) and was sort of laughing to myself that they could divert the amount of energy to ground, but they look cool and give me a false peace of mind (similar to wearing wearing a helmet while being shelled in Bosnia)
 
More than one person has had a helmet protect against fragments and oblique hits from bullets. Maybe this is similar?
 
I've wondered the same. I feel a direct strike, nothing will save you.

Most of the time it's nearby strikes that take things out. These near strikes are more manageable, and the surge protectors like the midnight SPD would probably stand a chance I suppose.
 
I do have Midnight SPD’s on each combiner and have been tickled by lightening with no fails .......but I have not suffered a hard strike on the main array,s

I suffered a direct hit on my wi-fi repeater on the 30’ Rohn communications tower, cooked everything, panel, zener diode battery and two routers configured as a wi-fi repeater, wind vane, anemometer, data logger
 
No solar here, but we had a lightning strike last year about 30 FT from my pool area which is surrounded by low voltage LED lights branching off into 6 different strings. Every single LED light at the end of each string was blown. All the other lights were fine. It was weird.
 
I've been hit by lightning, it took a couple hours to repair. This year I looked up at a small panel that powers my garage. It had a hole blown thru the back. So, something happened. Lightning does strike twice. I got several hundred MOV I could place around to protect things. I can't see any reason to waste the effort.
 
LED is a diode, easily blown by reverse over-voltage. If protected by a parallel diode in reverse polarity, might survive. But not all diodes are fast enough. For protection, speed to begin conducting is all that's needed; time to turn off isn't important. Series resistor for current limiting would protect against higher energy.

Indirect strikes could be conducted through dirt and grounding. Also by inductive coupling, pretty easy calculation of a gazillion amps at some distance, to a parallel wire of some length. This is where a few kV and a few Joules comes from, that TVS can handle. It is not tightly coupled like a transformer, where 100% of energy in couples to output.

Rather than calculation, or in addition to it, best for the situation to be tested with a lightning rod and sample wires with protection devices at various distances. Probably this is published somewhere. What we would need is a site survey determining closest likely strike, and history of strike power in our area. For industrial scale protection this is likely known. Anybody got resources for us DIY crowd?
 
HRTKD said:
Well, I don't know what a metal-oxide varistor is, so your humor is lost on me. Sorry.
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It's what's in surge protectors to absorb the hit during a surge.
The Hughes Power Watchdog 30a and 50a models have replaceable surge modules, so you don't have to throw the unit away after it protects your RV from a surge event.
 
The longer the distance, the easier it is to protect. UL has far different requirements at a service entrance than at an outlet some distance away. Slowing down the rise time of the wave is what needs to be done. A few wraps of wire around a wire bar will add protection before a MOV or any other surge protector. I've seen people coil up the ground lead of a protective device to make it look pretty. These leads should be as short as possible. Lightning need an easy path. I know this radio tower installer and he ties knots in power cords and swears by it. He says it will blow thru the insulation at that point. That is a coil and lightning doesn't like inductance.
 
My question on this post is not that lightning strikes can happen (they do), or that they can be very destructive (they clearly are), but is there any real world, empirical evidence of commercial surge suppressors preventing damage..??
 
mvonw said:
My question on this post is not that lightning strikes can happen (they do), or that they can be very destructive (they clearly are), but is there any real world, empirical evidence of commercial surge suppressors preventing damage..??
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Ya, I’d like to know if buying something like Midnight Solar SPD are worth it.
 
mvonw said:
I was curious if anyone has firsthand experience with an ocpd actually protecting your inverter/home from a lightning strike?
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Yes, I have seen SPD's sacrifice themselves and the equipment survived a lightning induced surge.

I believe it's safe to say that an OCPD's (breaker or fuses) are designed to protect against overcurrent but not lightning per se. SPD's protect against overvoltage and are specifically designed to protect against surges.

My experience, observations and working with people much smarter than me over the years have led to believe the following.

-If your equipment suffers a direct strike it's most likely a goner regardless of what protection you have on it.

-The best way to project against a direct strike is to make sure your equipment doesn't look any more attractive than the tallest object around you.

-Proper grounding bleeds off potential charge (static from wind?) on the metal structure holding your array or wind turbine thus they look no different to bolt of lightning that the oak tree a 30 yards away.

-Most lightning damage comes from induced surges and that's where SPD's are effective. I've done some work at both off-grid site and grid connected sites. Grid tied systems have for more instances of damage than off grid. A quick field autopsy of removing the inverter's cover quickly reveals that damage came in on the AC side brought in by the grid.
 
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