Grounding question?

stmar
stmar Solar Expert Posts: 370 ✭✭✭
We were hit by lightning a few years back and I found that they had multiple grounds that did not go back to a common point. I rectified that situation and made sure all grounds were tied to a common point. Am I correct in my thinking? Should the solar panel and wind turbine and inverter grounds tie into the ground for the AC (grid)? I may be over thinking it, I was looking at the way I want to wire up the generator circuit to the inverter and questioned myself as to where I could tap into the ground?
The generator would then be grounded to what I use for a ground for my generator to inverter circuit when I plug the extension cord into the receptacle on the generator. In other words I don't need a separate ground wire for the generator.
I also have my battery bank tied into the common ground by a wire to the negative terminal. Is this how other people ground their battery banks?

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grounding question?

    Yes. Single point grounding is the norm.

    And no. Because Electrical Safety Ground is not lightning protection.

    Since the solar panels' frames and mounts are more likely to be energized by stray Voltage in a lightning-strike area rather than any fault in the electrical system it's better to give the frames their own ground wire running outside the building to the ground rod. This may be the same ground rod as the power system uses or it may be a separate rod. The same with a wind turbine & tower.

    Although some (including the NEC) would not agree with this.

    Another thing is to have lightning arrestors at least on the lines most likely to get energized: i.e. the PV and turbine wires.

    It is normal for the generator to run its wires, including ground, in to the main power system and connect all there. It does not need (nor should it have) a separate external ground rod.

    It is also normal to tie battery (-) to the single point ground rod.
  • stmar
    stmar Solar Expert Posts: 370 ✭✭✭
    Re: Grounding question?

    Thanks for reaffirming that, I figured I was just over thinking it. My frames and poles do have their own ground wires. I was under the impression that if there were multiple ground points, not terminating at a common point, it created some type of environment that was more susceptible to lightning strikes. May just be an urban/rural legend but you get kind of nervous after you get hit and will do most anything to minimize another occurrence, lol.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Grounding question?
    stmar wrote: »
    Thanks for reaffirming that, I figured I was just over thinking it. My frames and poles do have their own ground wires. I was under the impression that if there were multiple ground points, not terminating at a common point, it created some type of environment that was more susceptible to lightning strikes. May just be an urban/rural legend but you get kind of nervous after you get hit and will do most anything to minimize another occurrence, lol.

    Nope. It's confusing lightning protection with what happens when you have multiple separate ground points on an ESG circuit. This is where you can create a 'ground loop' wherein a short may actually energize some part of the system rather than have its Voltage pulled down to zero due to differences in resistance of the loop. When multiple ground points are used they need to be tied together correctly so that all the rods essential form a single grounding point.

    Nothing causes confusion (or arguments) like grounding.
  • jaggedben
    jaggedben Solar Expert Posts: 230 ✭✭
    Re: Grounding question?
    Since the solar panels' frames and mounts are more likely to be energized by stray Voltage in a lightning-strike area rather than any fault in the electrical system it's better to give the frames their own ground wire running outside the building to the ground rod. This may be the same ground rod as the power system uses or it may be a separate rod. The same with a wind turbine & tower.

    Although some (including the NEC) would not agree with this.

    The NEC has gone back and forth.

    690.47(D) was inserted into the 2008 code, then removed in the 2011 code, and now it's back in the 2014 code, and now there are already those arguing it should be taken out on an emergency basis.
  • stmar
    stmar Solar Expert Posts: 370 ✭✭✭
    Re: Grounding question?

    I can count on one hand how many times I have actually watched/listened to a 20 minute long informational video. This one was well worth the time, it actually made sense without a lot of tech jargon. I am sure there are other opinions out there, as evidenced by the code changes back and forth. Thanks for the input, it is truly appreciated.
    jaggedben wrote: »
    The NEC has gone back and forth.

    690.47(D) was inserted into the 2008 code, then removed in the 2011 code, and now it's back in the 2014 code, and now there are already those arguing it should be taken out on an emergency basis.