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zorro
Member
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# Posted: 3 Jul 2023 16:43 - Edited by: zorro
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I was at the camp this weekend and had the worst electrical storm i have ever seen
Lightning struck twice in what felt like a 50' range from the cabin and that and the thunder actually shook the cabin - twice!
(I have a home in FL but have never seen lightning like this, ever!)
2 other camps in the area also have parts of their system impacted
I have 4 ground rods buried in the ground as well as 1 for the panels
However, it looks like my Inverter got fried
I have tested the voltage from the CC and that still shows output, i tested all the panel fuses and they all seem fine, but nothing is coming into the cabin in terms of powering the outlets, lights, etc
With hindsight, it looks as though i should have turned off the inverter as soon as I was aware of lightning in the area - I didnt know that!
So 2 questons.................
anything else i could have done to protect the system or need to do going forward?
And I had a Samlex 1500W Sine Inverter 24V (hard wired to the Panel Box)
Any recommendations for a similar Inverter around the $300-$400 price range with Hard wire capability?
Or I may need to get the Samlex again, though that is a bit pricey
I know that is low, but need to try to keep it at a reasonable budget at the moment
Thanks
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Nobadays
Member
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# Posted: 3 Jul 2023 18:20
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That sucks!
The engineer who put our final design together used Midnite Solar surge protection devices both at the Combiner box and between the batteries and the inverter.
I think these: HERE
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ICC
Member
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# Posted: 3 Jul 2023 18:47
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Quoting: Nobadays Midnite Solar surge protection devices
Those are an absolute necessity, IMO.
My cabin setup has one at the panels, one at the CC, and one at the inverter as Nobadays stated. Plus I have an AC version wired into the AC service panel. I like them as they have the blue LEDs, which indicate serviceability. I have had to replace one because the array was struck enough to wear it out. That was back a few years and came in under their warranty.
I like those pure sine wave Samlex inverters. That is what my cabin uses; 24 VDC, 1500 watt.
I use a disconnect cable and plug assembly between my PV array and the CC. My PV panels are ground mounted about 15 feet from the end of the cabin where the CC is. I have a 10 gauge cable with a plug on the end that connects to the PV array. There is a Midnite combiner with a breaker before the receptacle where the cord plugs in. In lightning season (July thru September), when leaving the cabin I would always unplug and coil the cable to leave a 15-foot gap for lightning to jump. The rest of the year I would not bother to disconnect and would let the CC keep the batteries charged through the winter.
Now the cabin has a lithium battery and I disconnect before leaving every time. I also disconnect when I am there and there may be lightning activity.
I also have air terminals (lightning rods with a modern name) on the cabin, shed and garage roofs. Braided ground cables connect to a system of earthing points ( my preference of naming). In total, I have 4 eight foot copper coated driven ground rods and three buried 18" square sheet copper ground plates. The plates and rods were placed in slight depressions I made with the intent that rain water would flow to those spots and keep them moist for better conductivity.
My impetus for doing all that was a lightning strike that took out every device with electronics as well as the CC and inverter. Even a simple snap switch used to activate the blower in my propane wall heater blew apart. GFCI's were toast and a ceiling fan speed controller blew apart. I was not present so I missed the excitement and fireworks.
I also have several of the Midnite surge suppressors on the home installation.
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zorro
Member
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# Posted: 3 Jul 2023 18:52
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Thanks guys
I need to look at those midnight surge protectors as I have zero in place
Suppose I was lucky only losing the Inverter - could have been a lot worse
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FishHog
Member
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# Posted: 3 Jul 2023 20:41
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Are you sure it’s not just a fuse in the inverter. Pull the cover and check for a blown fuse before buying a new unit
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zorro
Member
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# Posted: 3 Jul 2023 20:47
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Thanks
I pulled the cover
There are 5 x 20amp blade type fuses
I tried everything to remove them and could not get them out - they did not appear to be soldered to the motherboard but they would not budge at all
There is then 1 other fuse soldered to the motherboard
I have a friend who has taken the unit away to try to test it for me in the hope it is just one of the fuses
I tested them on the board with a multimeter and they appeared to be ok - but from from what I have read, testing in situ can give false positive readings
But hopefully my buddy can get them out and rest them better than I could
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Brettny
Member
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# Posted: 3 Jul 2023 20:59
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Do you have underground wireing that runs into the inverter?
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zorro
Member
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# Posted: 3 Jul 2023 21:02
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Hi
There is underground wiring from the Panels to the Charge Controller but no other underground wiring - there is a 6’ ground rod connected to the panels if that makes any difference
Batteries are around 3’ off the ground and cables come straight into the cabin to the electrical system
So nothing else runs underground
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DaveBell
Moderator
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# Posted: 3 Jul 2023 21:31
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There is a device called a Megger ($$$$$$) that measures grounding conductivity. Have an electrician come out and evaluate your grounding system. A spy station around Berlin Germany had a grounding problem because it was built on top of war rubble. The solution was to install a grounding grid like rebar in cement slab. The Florida sandy soil may not provide effective conductivity.
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zorro
Member
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# Posted: 3 Jul 2023 21:39
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To confirm
I have a home in Florida but the cabin is in the Adirondacks
However, that is almost 100% sand
When digging down for the pillars, it was almost entirely sand down to 4’ and not a single rock or piece of earth/clay to be found anywhere!
And we used 6’ rebar as the grounding rods
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DaveBell
Moderator
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# Posted: 3 Jul 2023 22:30
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Ground rods are clad in copper. I'm not sure how conductive rust is.
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zorro
Member
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# Posted: 3 Jul 2023 22:38
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Yeah maybe I am wrong with that - looked like rebar to me!!
My electrician/solar installer fitted them - so hopefully not simple rebar
Likely my misrepresentation of what he installed………. I hope!
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ICC
Member
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# Posted: 4 Jul 2023 00:11 - Edited by: ICC
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Grounding rods are 8 ft long and copper clad steel. 1/2 or 6/8" diameter. 8 feet is code length.
Iron oxide, rust, is a very poor conductor.
You can check resistance of grounding rods with a multimeter. You check the ohms between 2 rods.
The NEC requires a maximum resistance of 25 ohms ground resistance. Less is best. The International Electrical Testing Association recommends 5 ohms or less.
Multiple rods should be no closer together than 6 feet and connected to each other with a continuous wire. 6 AWG wire for most residential under 200 amps IIRC.
For a lightning protection system with air terminals wires are much larger. Aluminum conductors of 5/8″ diameter braided cable consisting of 26 strands of 14 gauge aluminum wire for example.
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zorro
Member
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# Posted: 4 Jul 2023 06:57
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Thanks for the detailed explanation - much appreciated
Not back for around 6 weeks and I will check then - hopefully they installed the correct items!
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Brettny
Member
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# Posted: 4 Jul 2023 07:04
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The ADKs is very sandy soil. NY has had some really heavy thunder storms in the last month.
If your feeling like that lightning hit 50' away no ground rod is going to save sensitive electronics.
I had a friend with a inground pool that backup to power lines and even had large trees 60'+ all around his property. One summer they got hit and it melted every single breaker in his electrical pannel
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zorro
Member
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# Posted: 4 Jul 2023 07:26
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Agreed - it feels like a Sandy beach all around the cabin and at least to a depth of 4’
Thanks for the info
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gcrank1
Member
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# Posted: 4 Jul 2023 09:51
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With fully charged batteries you maybe can run just the inverter for a good long time with it physically disconnected from the solar system during a storm? Though I read with interest that ICC coils his cable and places it 15' away for a safety jump distance.
Be aware that lightening can strike pretty much 'out of the blue' from a far distance from the apparent storm.
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ICC
Member
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# Posted: 4 Jul 2023 16:05 - Edited by: ICC
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I used Andersen SB connectors in a triple configuration for the plugs. The cable is flexible 10-3 like the stuff used for 30 amp RV shore power cords. There is a disconnect (midnite solar DC breaker that is tripped to off before connecting or disconnecting to avoid arc flashes.
This is not NEC approved and could result in injury. (That's the lawyer in my family talking 😉)
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Brettny
Member
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# Posted: 4 Jul 2023 16:51
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I dont believe lightning struck the pannels in this case. The CC would be toast. With sensitive stuff lightning dosnt even have to hit it to fry things.
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ICC
Member
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# Posted: 4 Jul 2023 17:05
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Right. Lightning may have struck the cabin and backfed into the inverter. But that does not diminish the hazard of future strikes taking out other portions of the system.
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zorro
Member
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# Posted: 4 Jul 2023 17:11
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Yeah I am pretty sure the CC is unaffected
Still seems to be fully functional showing all the battery reading and giving a voltage output when I used a multimeter on it
At the first lightning strike which was the closest to the cabin, all the lights turned off immediately and they are all in the inverter/batteries
I checked the fuse panel and all fuses seemed to be ok
I went out and checked the batteries and they all seemed fine
And as I said, CC seems to be functioning
The only item which seems to be completely dead, with no lights and nothing showing is the inverter
I opened up the inverter but no visible damage, though I realize that is highly sensitive electrical components and may not see any damage
I have a friend who is going to run some tests and see if maybe the 6 internal fuses blew or if it is basically toast
Hopefully find out in the next week or so
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ICC
Member
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# Posted: 5 Jul 2023 21:21 - Edited by: ICC
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Samlex fuses are soldered to the circuit board. They protect the DC input side. Since the CC was not damaged I would guess the problem (lightning) hit the AC side and back fed into the inverter. Fuses may very well not be the problem. But your friend should be able to tell. Good luck.
The fuse info is according to the user manual I have.
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zorro
Member
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# Posted: 5 Jul 2023 22:06
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Thanks for the info
Confirmed today that all the fuses are blown
There is also power “fluctuations†across the full board
So from what info I have, the inverter is gone
I have ordered a direct replacement and should have it shipped this week
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