Grounding?

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cdherman
cdherman Solar Expert Posts: 32 ✭✭
In spite of my original intents, I ended up hiring someone to install my system. I am one of those guys that contractors hate usually, as I end up finding problems in their work.

Here's my concern:

They grounded the rails (Ironridge) with a nice #6 stranded wire, but they ran the ground back INTO the structure, tacked it onto the wood trusses inside, and for a while they tacked it right next to some other romax lines.

The structure is a large shed. So they found a spot where there was no floor and drove a proper 8' ground rod, no problems there.

But it seems stupid to me (having seen what lighting strikes do up front and personal) to have grounded the whole thing INSIDE the structure....

If there's a serious hit, that ground line's going to fry, maybe even jump over to the AC circuits. Its stapled to wood materials = fire.

Why not just leave it on the outside of the structure and route it to a ground rod out there?

Maybe I am just over cautious -- I have seen what a lighting strike does though, and it ain't pretty......

Does any code govern grounding of the array? Should it be on the outside? More than one ground rod?

Thanks in advance...

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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Grounding?

    these questions you should direct to the installer as to why he opted to run inside the shed, but that is key here as it is an unoccupied shed. the extra effort he went through to ground inside does not make much sense to me though.:confused:
  • CaptTurbo
    CaptTurbo Solar Expert Posts: 66 ✭✭✭✭
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    Re: Grounding?

    My install is only a few weeks old now and my installer did the same thing. All the wires including the ground from the array run through the roof, into the attic, and to my garage where the inverters are.

    The final point where the ground rod is located is just outside the North wall of my garage by the battery bank. I have the same concerns as the OP about running the ground through my attic. The inspector did sign off on the job though so I guess it is OK to do this.


    Edit: I just went out and checked and see that they did re-route the ground after the county inspector's visit. There was a small list of complaints that he had and I think that must have been one of them.

    The ground now comes off the array, down under the eves, and then goes along the house at the top of the wall bundled with my cable and WebBox lines
  • BB.
    BB. Super Moderators, Administrators Posts: 33,471 admin
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    Re: Grounding?

    A couple threads about Lightning:

    Off Grid Grounding Technique?
    Another Question, this time about Lightning

    Note, the above are discussions, not a do A, B, and C--and you will be "safe". There probably is no such thing with lightning. Several different techniques are discussed--and a few of those posters even have experience with lightning. :cool:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
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    Re: Grounding?
    CaptTurbo wrote: »
    ....

    The ground now comes off the array, down under the eves, and then goes along the house at the top of the wall bundled with my cable and WebBox lines


    Isolate the high voltage, and then bundle it with the low voltage??
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Grounding?

    This silly old man thinks ground conductors, especially those with a potential for being hit with lightning, are supposed to be kept away from other conductors (including 'inadvertent' ones) and run down the outside in the shortest path possible without sharp 90 degree bends.

    Obviously this is not right, and one should really go to a lot of extra effort to increase the risk of fire hazards whenever possible. :roll:

    i added the word sharp as gradual rounded 90s can be done, but avoiding 90s all together if one can is a good idea for lightning may try to straighten your bend by jumping off of it to who knows where. niel
  • CaptTurbo
    CaptTurbo Solar Expert Posts: 66 ✭✭✭✭
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    Re: Grounding?

    I was thinking the same thing. The utility (FPL) has not signed off on the inter-connection agreement yet and I still owe Solar Source $1,000.00 for the last payment. I will raise the issue and see if they might want to seperate those wires a bit.

    On another note, I really like the guys from Solar Source and I'm pleased that SolarGuppy advised me to call them. If there is something that isn't right I'm pretty sure that they will change it for me.
    mike90045 wrote: »
    Isolate the high voltage, and then bundle it with the low voltage??
  • audredger
    audredger Solar Expert Posts: 272 ✭✭
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    Re: Grounding?

    In the "old days" when a lightning rods were installed on a building, the only horizontal run was to be found at the ridge. All other runs would be sloped toward the ground. And as Marc says, no 90 degree turns. In fact no sharp turns.
    I would never bring a lightning ground into a building! Like a proper lightning rod, I would also use a stand off to carry the "rod" down the building.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Grounding?

    Niel; your clarification is welcome! That is what I meant, of course. It's those sharp bends that get you; the lightning sometimes deciding to take a 'shortcut' as a result. But naturally you have to be able to take 'right turns' now and then - just do it gradually.

    And by 'lightning' we mean the stray Voltage that saturates an area where lightning is hitting. An actual lightning strike - millions of Volts, thousands of Amperes, 50,000F, megajoules of energy, capable of leaping miles of distance - will blow anything you've got to smithereens. :cry:
  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
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    Re: Grounding?

    Normal electrical systems are grounded. That ground from the racking/frames is an "equipment ground". It is there for basic safety and is IN NO WAY intended to conduct lightning.

    Therefore running that ground inside is not a problem.

    If you install lightning rods then the wire from them to the ground has to be outside.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
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    Re: Grounding?
    dwh wrote: »
    Normal electrical systems are grounded. That ground from the racking/frames is an "equipment ground". It is there for basic safety and is IN NO WAY intended to conduct lightning.

    Therefore running that ground inside is not a problem.

    If you install lightning rods then the wire from them to the ground has to be outside.

    Intended to, no. Likely to? Maybe.

    But seriously; do you have any idea why they went to the extra effort to put the grounding wire inside when running it outside would be easier? Is it safer that way? Some kind of code reg?