Lightning and inverter

gww1 · August 2014

I don't know if I should put this here or in "reveiw".

About 8 days ago I lost one of my outback inverters during a storm. I ordered the three circuit boards from outback and installed them today and things seem to be working.

I lost my internet for the same amount of time. I have hughs net and don't think I am going to be impressed.

I did learn one thing on the inverter. I bought mine used and was mighty worried about them.

A new one is about $1500 or more new. The boards to repair cost $800 and something but when you send your old ones back outback refunds $300 something so the total cost is around $460.

I like that my 9 year old inverters can still get parts and it takes some of the fear out of buying used as long as you get it cheep enough to compensate.

I have seen 6000 watt loads on these inverters and they are impresive. I don't like that they break but it is nice to know it didn't cost $1500 to replace and seems to be, as new, when fixed.

The reprograming takes a bit of thinking as you usually only do it when you first install.

The repair was pretty easy except for the weight of the stuff. almost to heavy for a wimp like me.

I wrote this incase anyone was considering buying used or just curious.

Lightning sucks and insurance in america is only for big losses. Even if you lost more then your deductible you would have to worry about being cancelled if you make a claim.

Cheers
gww

Mountain Don · August 2014

Re: Lightning and inverter

I'm happy to hear you were able to repair the unit. You did not mention if there was other damage. We lost our VFX3524M about 6 weeks ago in a severe thunderstorm in NM. We also lost the FM60 and a TV, DVD, A/C and a generator. As well the DC circuit breaker right before the FM60 input actually blew apart. We had delta arrestors and the ends blew right out of them. The PV panels are 325 ft distant in the sunny spot of the forest and some of the conduit that houses the #2 wires blew apart at the joints. All in all it must have been an exciting event. We were absent and after surveying the damages are glad we were away. Three trees within a 30 foot distance from the cabin show extensive damage; bark blown off in chunks and strips.

We have now improved the lightning protection to the tune of almost $1000 of hardware, rods or air terminals plus a lot of wire and ground rods and plates in the earth. Also improved electrical system grounding in the form of more connected rods in the earth. The soil may not be the most conductive but the final tests had 2 to 6 ohms between grounding rods/plates. We now have five new MN surge suppressors plus a couple new Delta for redundancy. Running on a back up Samlex inverter at present. The VFX will be looked at soon. The FM60 has been replaced with a MN Kid as it fits the panel & 24 VDC battery bank very well.

niel · August 2014

Re: Lightning and inverter

mountain don,
wow, sorry for your loss. it sounds like a direct hit that transferred down to the rest of your equipment. it sounds like your lesson was learned and you've taken good steps to help prevent such damage from occurring again. no guarantees, but i'm sure you've increased your odds of survival.

gww1,
i do hope you have good grounds and other such things to minimize this from happening again. yours could have been the emp only that did the damage. even if you do have good grounds and made other provisions for reducing damages and still received damage then it is time to take more steps in its prevention.

DMJ72 · August 2014

Re: Lightning and inverter

What do you guys reccommend for lightning .. in terms of grounding. I have Midnite SPDs everywhere, should I ground my panels to an independent grounding rod? At present they are tied to the main house ground which is tied to the neutral @ the service entrance.

gww1 · August 2014

Re: Lightning and inverter

Thanks for the replies.
mounten don, sorry for your troubles. I have lived here for almost 20 years and have had atleast 3 prior strikes with damage simular to yours altough never quite as extensive. I did have a copper line to a refridgerator ice maker burst one time but was there and stoped the water quickly. The flash from it was impressive though.

Neil, I don't know if my grounding is that good or not. My turbines are ungrounded, my pv's are grounded at the aray about 200' from the inverters and my house ground is the original from 40/50 years ago. My previous strikes took out things like vcrs, phones, modems, etc.. When it came through the phone lines it left dark spots on the walls and burnt smell so I am probly lucky to still be living here and not burnt out.

dmg7 My pv ground is at the solar some distance from my house. If you figure grounding out, let me know as there are numorous post on this site and I am still confused so I just did it as I did it.

Thanks for the comments and good luck mounten don. The outback fix is fairly strait forward but will surly add to the cost of the thousand you have already spent. outback does have vidios on youtube.
good luck
gww

SolarPowered · August 2014

Re: Lightning and inverter

Lightning strikes love battery banks for some reason. Most GT systems don't suffer the type of lightning problems that Off grids do.
Its more perplexing because the frequency that lightning strikes, is not the same frequency that DC/AC systems operate at.

BB. · August 2014

Re: Lightning and inverter

Interestingly, years ago, our old (now retired) Admin from NAWS said that, for off grid systems, it was generally the AC output of the OG Inverter that was most often fried by lighting strikes.

For what it is worth.

-Bill

Cariboocoot · August 2014

Re: Lightning and inverter

BB. wrote: »

Interestingly, years ago, our old (now retired) Admin from NAWS said that, for off grid systems, it was generally the AC output of the OG Inverter that was most often fried by lighting strikes.

For what it is worth.

-Bill

I think you'd need to look at all the systems involved which generate the statistic and find the common element. In all likelihood it's the sheer length of AC lines making for a larger antenna to receive the EMF from the strikes rather than the type of power on the lines. The DC side of things, other than the PV input, is usually quite small and short presenting less of a 'target' for strikes.

Unless there is some sort of frequency-convergence factor at work. Difficult thing to study, really.

Organic Farmer · August 2014

Re: Lightning and inverter

Talking among neighbors the off-grid homes do seem to have stories about lightning strike losses.

I am not off-grid yet, but working on it. This morning I finished grounding our solar-panel array. 6awg copper to each panel frame, connected to the ground bus in the combiner box, and to it's own ground rod.

I already installed two lightning rods on towers, one over each end of the array. Each of them are separately grounded.

And the solar-panel array supports are grounded likewise.

The combiner box has a surge protector. The panel with Charge-Controller and Inverter has two surge protectors.

I did 20 years on subs, every pier we surfaced alongside of has telephone poles, at 40' intervals along the pier. All with lightning rods on top and high-tension wire strung horizontal between lightning rods. So carrying equipment up out of the boat and on the pier we are always underneath that protection. Copper rods and wire are cheap as compared to loss of life and/or equipment.

I am thinking about maybe stringing high tension wire between the lightning rod towers.

gww1 · August 2014

Re: Lightning and inverter

I have an underground wire from the inverter to the house for about 70 to 100 feet. The dish that give me internet is on the house. I am not sure if the dish is plugged into one of the inverter circuits or not but the eye on the satalight and the modem were also taken out. Probly not a hit but just really close lightning.
gww

Mangas · August 2014

Re: Lightning and inverter

Last year, I had a nearby lightening strike.

Lost the satellite TV modem, one of two furnace/AC handlers mother board and one of two underground water storage tank motors.

Everything else came through OK including the four inverters. Interesting how lightening selectively takes out electronics and motors.

I was struck once in my truck which is a whole other story. . .

mike95490 · August 2014

Re: Lightning and inverter

DMJ72 wrote: »

What do you guys reccommend for lightning .. in terms of grounding. I have Midnite SPDs everywhere, should I ground my panels to an independent grounding rod? At present they are tied to the main house ground which is tied to the neutral @ the service entrance.

IMHO - panel frames should be grounded as close/directly as possible to the panels. And if you are in a high lightning area, set up some Franklin Rods to take the main strokes, not your house ridge or PV array.
Deltas and SPD's are good for induced voltages, but, to absorb killowatts of power, they just will vaporize. Big difference between a fence charger and a Thunderbolt from Zeus !

Grinnin · August 2014

Re: Lightning and inverter

gww1 wrote: »

I don't like that they break but it is nice to know it didn't cost $1500 to replace and seems to be, as new, when fixed.

In 2002 my charge controller stopped charging but was warm. There had not been lightning "near" here, but perhaps 10 km away. Which was apparently "near" enough.

The repair was not expensive but it left me feeling vulnerable -- such delicate electronics that could leave me in the dark (metaphorically if not quite literally).

During the repair the mfr asked about how my system was grounded and suggested some changes although I don't recall what I changed.

I have had no problems with the "delicate" electronics since then through many storms.

niel · September 2014

Re: Lightning and inverter

gww1,
sorry for the delay getting back in here as i don't frequent the forum as much as i used to. the turbines being unprotected is a path for lightning or its emp and should be protected with an spd for each of them.

i am going to assume you have a ground lead coming back from the pvs to your place so as to go to the ground point on the cc and on to the eventual ground/neutral tie point in your main electrical box. this can pick up emp and pass it to the house just as well as the pv + and - can with 200ft distances. this is the way wiles set things up. left up to me i'd take the ground wire coming back with the pv wires and put it to the ground rod used for your electrical service panel and not allow it to enter the home at all.

i am curious of the location of the sat dish getting possibly zapped. if way out by the pvs this should be grounded to your pv ground rod and put an spd on the dc lines at the sat equipment to go to the pv ground rod also, but see if you can get a surge protector for your 75 ohm coax cable.

here is a gas discharge type example which tends to protect well, but often only once and is a bit more expensive.
http://powerfulsignal.com/lightning-surge-protector-75-ohm.aspx

this example from ebay is probably an mov type and is much cheaper than the gas discharge type and will often protect multiple times.
http://www.ebay.com/itm/BNC-75-Ohm-CCTV-Video-Surge-Lightning-Arrester-Protector-SPD01-V40A-/310873525707
(note that this has the wrong connectors on it. sorry for my oversight, but a search for the proper ones are with f connections.)

have both the dc lines for the sat equipment and the coax cable protected at both the dish and before entering your home. if in doubt you can contact your sat company to see if they offer up such things or can tell you where you can get it from. i suspect you had a side bolt or a strong emp hit the dish. i am assuming the dish carries your telephone service of course.

oh and if the sat dish is closer in like less than 40-50ft you could use just 1 coax cable arrestor and 1 spd, but putting them on both ends is extra protection one can use with closer distances too.

if i ever take way too long to get back to anybody then try contacting me from a pm to cariboocoot and he can let me know via email as i do check that every day or 2.

gww1 · September 2014

Re: Lightning and inverter

Niel

i am going to assume you have a ground lead coming back from the pvs to your place so as to go to the ground point on the cc and on to the eventual ground/neutral tie point in your main electrical box

I don't have a ground wire from the combiner box to the cc. The solar aray is 200' from cc and grounded at the aray. The cc is grounded at the inverter and from the inverter to the house "70' away" the inverter is ground through the ac line to the main panel. The sat. dish is on the roof of the house and is grounded to the house ground rod.

I worry not about time of responce as beggars can't be choosy when asking for advice from volinteers who have there own busy lives. I am thankful for every peice of good advice even if I ezasperate folks cause I don't always listen.

Thanks
gww

BB. · September 2014

Re: Lightning and inverter

There are lots of good reasons to tie a 6 awg wire between all of your various location (array, power shack, home) with, at least one ground rod, at each location.

If adding a 6 AWG cable to tie all of the ground rods together is not going to happen--I would suggest that you install Midnite SPD's at each location (at the array combiner box, at the power shack DC input and AC output, and at the home AC power input (or several if you have off grid, generator, AC mains).

http://www.solar-electric.com/catalogsearch/result/?q=midnite+surge&cat=0

And adding the SPD's at each location is a good idea anyway--regardless of the 6 awg ground tie or not.

-Bill

Organic Farmer · September 2014

Re: Lightning and inverter

gww1 wrote: »

... I don't have a ground wire from the combiner box to the cc.

Assuming that every component has it's own grounding rod, why wouldn't you have a ground wire between each component?

I grew-up on farms. When the power comes from the grid to your meter, you have a ground rod right there to establish 'ground' at that spot. In many cases, the meter box is on the side of the house so that ground rod works for the entire house. But lets say that you run a power line 100' away to a barn with a sub-panel. That sub-panel then has a circuit to your milking parlor. When I was a kid, there were many farms that found their cows stopped giving milk. After years of research they found 'stray-currents' were zapping the cows. Having a ground rod at the barn sub-panel fixed it. Even though all grounds were connected, it becomes an issue.

Today many farms will have a 200amp panel at the house, with it's own ground rod. Then a 100amp sub-panel at the barn, with it's own ground rod. Then a 50amp milking parlor sub-panel [maybe with only two 15amp breakers in it, one for lighting and one for the milking machine], with it's own ground rod. Obviously the wires from main-panel to sub-panel to sub-panel all include ground wire.

BB. · September 2014

Re: Lightning and inverter

A lot digging?

-Bill

gww1 · September 2014

Re: Lightning and inverter

All I know is, I spent a lot of time reading and harrassing poeple on this forum and others trying to get it right. My final decision was as the panels were 200' away, why bring lightning from them to the ac side of the house. If I reamember (solarguppi?) believed in ungrounded arays. I haven't bought the lightning arresters cause I am cheep and also needed a break after installing everything. I may have just payed for it, Though my house has been hit before and things broken prior to solar. Also I do have lightning rods, They are called wind turbines, ha, ha...
Cheers
gww

BB. · September 2014

Re: Lightning and inverter

Yea--Solar Guppy does (last I heard) believe in floating his solar arrays/frames.

From a 2009 thread:

Another question, this time about lightning

Here is one Solar Guppy "oldie but goodie" post on grounding:

Originally Posted by Solar Guppy
Living in the lightning capital of the US, I never understood the concept of grounding the PV frames, that's a couple hundred square feet of lightning attraction that at best will vaporize the ground wire and at worst cause your home to burn to the ground.

PV cells don't touch the frame, the Jbox or MC box doesn't touch the frame, there is no way a panel defect can energize the frame.

One of the nice things about regulations, is that is ALWAYS up to the local inspectors to what is acceptable, regardless of what the NEC has written.

In all my installations, with full written approval of the local inspectors my frames are left un-bonded to anything. the last thing I want is to be waving a flag at the next bolt of lightning to say HIT ME HERE and that is exactly what grounding the frames do.

Each and every year I get about 20-30 hits within a few hundred feet of my home. Last year the street light got nailed and took out 2 inverters by backfeeding in the mains. That street light is less than 30 ft from the solar panels .. so I think its safe to say my preference saved my array/house from a direct hit!

I'm not sure how John Wiles became an expert in lighting issues and best practices of wiring to write regulations for the NEC, but where he lives I doubt he see the activity in his lifetime I see in one rainy season here in central Florida.

Part of a long thread discussing "What the Heck is NEC doing?"...

-Bill

Solar Guppy wrote: »

Sub,

If your getting permitted from polk county, Jim Legee is the head electrical guy and is the one that signed off on me NOT grounding the frames. He is a very smart, down to earth type and understands exactly the issue I was avoiding

If you haven't yet, setup a meeting with him to review you PV plans , you can contact him at the Bartow office of the building department ( polk county ). He is the one that will approve the application and will be the one for final sign off on the permit. When I expanded my system in 2007, he brought all the inspectors out to check things out ... 4-5 inspectors milling my about my solar stuff was fun

The system is in its 6th year, with hundred or so strikes near by every year, never once has the house or panels been hit, while many nearby objects at similar or lower heights have been.

My home is well exposed as well, I'm near the top of a 120 foot hill ( mountain in Florida ), I can see 30 miles to the east so its not exactly a low profile area lightning wise.

SG

Lots more in that thread.

-Bill

inetdog · September 2014

Re: Lightning and inverter

Organic Farmer wrote: »

I grew-up on farms. When the power comes from the grid to your meter, you have a ground rod right there to establish 'ground' at that spot. In many cases, the meter box is on the side of the house so that ground rod works for the entire house. But lets say that you run a power line 100' away to a barn with a sub-panel. That sub-panel then has a circuit to your milking parlor. When I was a kid, there were many farms that found their cows stopped giving milk. After years of research they found 'stray-currents' were zapping the cows. Having a ground rod at the barn sub-panel fixed it. Even though all grounds were connected, it becomes an issue.

Unlike people, cows are sensitive to just a volt or two potential difference between their feet. It is not the current that is the direct problem, it is the voltage difference that that current produces. And the current that in turn produces in the cows. :-)

A voltage drop of one or two volts across the neutral in a long feeder that would be insignificant in a residence can cause problems with livestock. One very simple measure, which is required for 2008 NEC and later is not to connect the neutral and ground wires at the barn but to connect the ground (EGC) to a local ground electrode.
Sometimes that is not even enough and instead of just a ground rod you need an entire equipotential grid, with a voltage ramp at the entrances to the barn.

niel · September 2014

Re: Lightning and inverter

gww1,
ok if i read this right you have the batteries and inverter in a remote building with the pvs farther away and grounded and ac fed to the house via underground wires from the remote building. at 70ft distance, i think you could put in a ground rod there if you wish to, but definitely it has to be grounded to the house ground rod at the very least. no spd protection on the pv + and - leads could still send a nice emp to your equipment even with wires underground. i doubt the problem was that in this last case as i believe the dish itself was struck. it is required that the dish be grounded to the house ground rod and if not then the lightning probably routed through the dish wiring in its search for ground potential. this can travel the power wires as well as the coaxial cable. usually it is sufficient to ground the case of the dish to the main rod, but a main strike is still capable of sending a jolt strong enough to take out anything downstream of any of its leads, including down the antenna cable leads. this equipment is highly sensitive and can blow out easy.

so my recommendations are as follows,
1 install an spd at the array or before it goes to the inverter for the pv +/- protection. both would be better, but if choosing 1 i would place it at the inverter.

2 put in a ground rod for the inverter at the remote building as this is far enough away from the house to warrant another rod if so desired. it is desired if you have an spd at that location. remember you are protecting the dc lines so the spd is to be matched for that voltage. i don't believe an spd to be needing for the inverter's ac output with the wiring being buried. you can ask on the midnite forum which spd they would recommend for your pv system voltage.

3 if not there already, put in a ground wire to the house ground rod from the dish.

4 put in a coaxial cable discharge block (or coaxial spd) to ground from the dish. if you have trouble figuring this or #3 out then talk it over with the satellite company that installed it for how to do this. sometimes the combiners that are present for some dish setups have a grounding screw present that one can attach a ground wire to and can be better as it grounds it before entering the building. if such is present then a grounding block is most likely unnecessary to be added.

hope this helps you some, but as usual there aren't any guarantees when it comes to lightning. summer storms are now on the decline as fall is getting ready to move in on us so you have some time to think about it and to act on it. just don't wait to do something during winter for obvious reasons and that seems to be earlier than usual for some.

gww1 · September 2014

Re: Lightning and inverter

Neil
The dish is connected directly to the house ground rod.

You have my set up correct. My inverter is grounded from the neutral that comes from the 50 amp fuse from the breaker panel in the garage and from the inverter it goes to a sub panel in the house. I took circuits from the house main panel and moved them to the inverter sub panel.

I used a 60 amp twelve breaker manual generator switch breaker panel. I have thought about this a bit and figure there is one thing about this system that I may not know.

I did not use the manual generator switch as it was designed in one way. That is that It has the main wires that you would normaly connect to the main panel through a breaker. Then it has one wire for each breaker that you disconnect a circuit from the house panel and move to the subpanel. Since I came from the panel in the garage to inverter to sub-panel in house, I did not hook the main wires from the generator switch wires to the house panel cause I didn't need that function. Sooooo, The only comon wire between the two panels in the house is the nuetral, which has to be done for a one wire connection to transfer the circuit, using one wire, to the sub-panel.

The one thing I really don't know: Is the garage box a line side imput from the meter and if so on a seperate ground of which I have never seen. Would this make a differance, IE: ground loop, not grounded at all?

Typing is punishment to me cause I am bad at it and at spelling. I wonder if the above is clear.

I have used this system flawlessly for a year.

Your post was clear and I am sure took some effort and I thank you for it.
gww

niel · September 2014

Re: Lightning and inverter

gww1,
if you are asking about loops due to the remote building ground 70ft away from the house main ground without tying them together underground then don't worry as the resistance of the earth should disallow the ground loops from forming with that kind of distance. if in doubt you could always run a wire under the ground and connect them.

the grounding of the ac neutral will not protect the input of the inverter or the antenna and power supply lines for the dish from sending emp or lightning up the line. the spd can help

gww1 · September 2014

Re: Lightning and inverter

neil
Thank you
gww

niel · September 2014

Re: Lightning and inverter

gww1 wrote: »

neil
Thank you
gww

you're welcome.

Lightning and inverter

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