diy solar

diy solar

Should I earth ground this system?

Danke said:
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Thanks , I love mikes videos… i have seen this but will watch it again as I have learned a lot since I last saw it and have forgotten about half of it…I think this is the vid he’s raisin hell about bad or multiple grounds and habits and the NEC ,and the mis-info on the topic…
Again ,thanks…jim.
 
Hedges said:
GFCI is a good idea, especially for outlets used when you will be outside the trailer.
Doesn't hurt inside, either, so long as not nuisance tripping.
(but don't use for refrigerator)
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In my view whole boat /trailer/RV RCD devices are the best way to cope with a unstable ground connector. You are protected irrespective
 
Goboatingnow said:
Well if there is nothing else, then it has to be ground rods. Of course yiu could develop a complete isolated floating pv mains supply and since it’s not grounded , there’s no ground fault paths and hence no utility in a protective wire at all !!
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Where can I learn more about floating pv mains? I'm trying to understand this and that might be a huge mistake because it seems, concerning grounding, the more I learn, the less I know.
 
stok said:
found this image on homepower
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In this illustration the PV frame grounding connects behind the grounding for the inverter/expensive stuff. In all i'm learning about grounding, it is always stressed that the ground connection occur in one place. How would this physically look as a mechanism? If you've got a rod, with a wire on the rod, is there some sort of bus where you'd connect an additional wire to the inverter ground wire ( just before the rod ) ?
 
Jim H said:
Honestly, I have read so many very impressive sounding opinions on grounding my system that’s mounted on a untility trailer ,till my head spins….it’s the only part of this craft I really cannot point to a science type answer that's agreed on …..
as soon as I do get what sounds good, 3 OTHER scientist come and say the other scientist was smokin somthing…this is totally frustrating.
All I wanna do is not electrocute myself out in the driveway By accident..
J.
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Agreed. Can I please just make toast and not be toast?
 
HLD said:
Where can I learn more about floating pv mains? I'm trying to understand this and that might be a huge mistake because it seems, concerning grounding, the more I learn, the less I know.
Click to expand...
Your not alone ….. I don’t think anyone really does totally …anybody….
the only good news about being a grounding expert for hire is if your wrong you won’t have any customer complaints….
ouch …
damn I likeed him…….
aw geezz.
I mean , what you Gona do…?
 
HLD said:
Where can I learn more about floating pv mains? I'm trying to understand this and that might be a huge mistake because it seems, concerning grounding, the more I learn, the less I know.
Click to expand...
As standard , your pv panel ouput is floating , in this regards earth is not a return path hence standing on the ground you cant get a shock via earth

Of course the pv panel is metal , potentially the mounting frame is metal , so now you can “ speculate “ fault modes. So grounding the frame and panel locally via a rod , would offer some local protection
 
Such a difficult subject to talk about because there is so much conflicting info on what is best. First, I watched hours of Mike Holt before building my system, specifically, I like the "electrical" common sense in this part of this video:
(from 51:10 -52:48) (and there's many other lectures he does concerning lightning pulses, etc.)

Anyhow, just a precursor, I have a small 3kW 7ft high wooden ground mount (no ground rod, even though I purchased one with the ground wire), that I just built with a Floating off grid AC300 w/Batteries using several GFCI's, not grid tied or plugged into shore power. The MC4's are plugged into an isolation switch (actually have 2 for a small set that I have) to use in a scenario described below so I can at least protect my AC300/Batteries..
https://www.amazon.com/gp/product/B0B1555FP5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Well, anyways, the first 10 of 10 days of me turning on my system, lightning every day and one of those 10 days, BOOM, a lightning Bolt hit my neighbor's backyard (wife saw the orange ball and I turned around to the window and saw the smoke). I thought that was it. Brand new panels, gone, up in smoke, new ones that I can't even buy again since they are sold out...anyhow, after the storm blew by, I switched the disconnect switches to on and they worked. The "pulse" DID blow out 3 of my 8 security cameras (plugged into shore power), tripped all of my (solar) GFCI switches (as expected due to detecting differential in current), and blew out 2 emporia switches that I had outside (solar) but not the pumps plugged into it. I dodged bullets those 10 days, even had hail and about a month later a hurricane with 90 mph winds. So a question, IF I did ground the panels AND the pulse DID travel up the ground rod, into the panel array, would that have been it? Something like the video above? I am unsure. I DO KNOW that a bolt hit feet from my house and they survived (knocking on wood right now). Here's a Mike Holt video of lightning striking but induction(?) happening many yards away from the strike.

Anyhow, that's my experience, so far...
 
My general sense as a beginner is that if you are in the house which already has one earth ground and even if your system is off grid, you do not have to ground?

However since I have a shed that has no power and is essentially a separate building on my one acre property, I do need to drive in eight foot grounding rod and ground the PV solar panels and my inverter.

Does this make sense?

I have watched Mike Holt videos also, but I think a lot of what he mentions is if your pv array is tied in to the main house/structure.
 
BlueMarblePA said:
My general sense as a beginner is that if you are in the house which already has one earth ground and even if your system is off grid, you do not have to ground?

However since I have a shed that has no power and is essentially a separate building on my one acre property, I do need to drive in eight foot grounding rod and ground the PV solar panels and my inverter.

Does this make sense?

I have watched Mike Holt videos also, but I think a lot of what he mentions is if your pv array is tied in to the main house/structure.
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Yes. If you have no house protective earth nearby then you have to create a local earth. That’s fine and most codes support that.

Just don’t ever inadvertently connect that protective earth to the house PE or another earthed protective circuit.
 
Goboatingnow said:
Yes. If you have no house protective earth nearby then you have to create a local earth. That’s fine and most codes support that.

Just don’t ever inadvertently connect that protective earth to the house PE or another earthed protective circuit.
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This makes sense to me. This is why I think the Phoenix is safer than the multiplus. The victron multiplus has an option for shore power ac input which would obviate the need for the shed ground rod. And it would make it unsafe to have a shed ground rod in addition to the grounding rod for the main home. The Phoenix has no option for ac input from main house
 
BlueMarblePA said:
My general sense as a beginner is that if you are in the house which already has one earth ground and even if your system is off grid, you do not have to ground?

However since I have a shed that has no power and is essentially a separate building on my one acre property, I do need to drive in eight foot grounding rod and ground the PV solar panels and my inverter.

Does this make sense?

I have watched Mike Holt videos also, but I think a lot of what he mentions is if your pv array is tied in to the main house/structure.
Click to expand...

If you drive in your own grounding rod, aern't you supposed to have two of them 8 feet apart?
 
OnGrid said:
If you drive in your own grounding rod, aern't you supposed to have two of them 8 feet apart?
Click to expand...
That is the current code, but on the other hand for many decades it was simply ok to just put in one grounding rod? I am planning to buy two of them and then see how hard it is to drive one in, and then decide on the other :)
 
Atomicpunk said:
Such a difficult subject to talk about because there is so much conflicting info on what is best. First, I watched hours of Mike Holt before building my system, specifically, I like the "electrical" common sense in this part of this video:
(from 51:10 -52:48) (and there's many other lectures he does concerning lightning pulses, etc.)

Anyhow, just a precursor, I have a small 3kW 7ft high wooden ground mount (no ground rod, even though I purchased one with the ground wire), that I just built with a Floating off grid AC300 w/Batteries using several GFCI's, not grid tied or plugged into shore power. The MC4's are plugged into an isolation switch (actually have 2 for a small set that I have) to use in a scenario described below so I can at least protect my AC300/Batteries..
https://www.amazon.com/gp/product/B0B1555FP5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Well, anyways, the first 10 of 10 days of me turning on my system, lightning every day and one of those 10 days, BOOM, a lightning Bolt hit my neighbor's backyard (wife saw the orange ball and I turned around to the window and saw the smoke). I thought that was it. Brand new panels, gone, up in smoke, new ones that I can't even buy again since they are sold out...anyhow, after the storm blew by, I switched the disconnect switches to on and they worked. The "pulse" DID blow out 3 of my 8 security cameras (plugged into shore power), tripped all of my (solar) GFCI switches (as expected due to detecting differential in current), and blew out 2 emporia switches that I had outside (solar) but not the pumps plugged into it. I dodged bullets those 10 days, even had hail and about a month later a hurricane with 90 mph winds. So a question, IF I did ground the panels AND the pulse DID travel up the ground rod, into the panel array, would that have been it? Something like the video above? I am unsure. I DO KNOW that a bolt hit feet from my house and they survived (knocking on wood right now). Here's a Mike Holt video of lightning striking but induction(?) happening many yards away from the strike.

Anyhow, that's my experience, so far...
Click to expand...
This is a really interesting story. Your system is floating and ungrounded, and despite all that, it seems like it worked?
 
BlueMarblePA said:
This is a really interesting story. Your system is floating and ungrounded, and despite all that, it seems like it worked?
Click to expand...
Yes, it has worked so far (but it's only been a few months), and with lots of close cloud to ground lightning in Aug/Sept and a Hurricane (Oct), it feels I have been "tested". In case it was missed, I have isolated my panels from outside to where they connect to the "expensive" inside equipment/batteries with the quick disconnect switch (mentioned above), which I cut-off during storms in the area. The panels = $2600, The Inverter/Batteries = $8900, so this way I can at least save the expensive part (you can NOT protect against actual direct Lightning strikes, but you can cut the pathway). A ground rod will NOT cut the pathway as well as a complete disconnect.
BTW, I inspect my system almost weekly for any potential defects (loose wires/stability). I even covered my MC4 wires with animal proof covers (Squirrels). I hurricane proofed my ground mount with hurricane straps, should be good to Cat 3/4 (didn't even budge a bit in 90mph winds). Also note, all the outdoor AC wiring is protected with GFCI protected outlets which have already have done their jobs, and have been tripped by close lightning strikes. Which actually seem to work better than my house GFCI outlets (when I used them).
Now, if I ever tied my system into the grid, I would have done things differently concerning ground rods. But this system is completely independent from house wiring.
 
So what's the take from all this in grounding rods? Should the panels and frames on a building be earthed to the home grounding rod? I've seen very conflicting responses on the subject
 
I'm in the process of building a ground mount for eight 445W bifacial panels. The support structure will be pressure treated 4x4's, with the panels attached to galvanized super struts. The array wire run will be less than 50ft to the inverter.

I will have a ground wire interconnect the panel frames.My question is where does this ground wire need to go? To a ground rod driven into the ground by the array? I've read this thread and still can't figure out if this is to code and/or safe? Or do I run the ground wire back to the inverter or the main panel where ground is bonded to neutral? Which way is to code, or are both?
 
Definitely a wire back to inverter, and from inverter to main panel. main panel.
 
My set-up will have a sub panel for 120v critical loads. I will have a single eg4 6500 feeding it. The inverter will have grid power going to its input, so that the grid will power crit loads and charging batts if necessary. Our house main panel (where I'll be moving the critical loads from) doesn't have the ground and neutral bonded, but the service pole panel which it's fed from, is bonded.

So you're saying run the ground array ground wire back to the inverter along with the two PV wires? The inverter has an input and output earth ground wire receptacle. Which ground should I use, or does it matter?

Just curious, but why is it not advised to connect the PV frame ground wire to a rod driven into the ground by the array? Will that create a ground loop issue?
 
Last edited:
Input and output ground wires should be the same net, so either or a ground bar in a panel is the same thing.
The idea is that if a PV wire shorts to frame, you want frame to be same voltage as earth and same as frame of other equipment.

"Ground Loops" may matter in some situations, but then it is really a return path loop (e.g. negative side of some circuits), not a ground loop. Generally OK to create a mesh of ground connections.

Discussions and links above talk about issues with extra ground rod at array (I think only if lightning creates a massive "step potential" between the two rods), but it may be required by code. I'm not sure. I know code in my area requires if wires are run to multiple buildings, they are all to have ground rods.
 
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