ground set up

ws9876
ws9876 Solar Expert Posts: 440 ✭✭✭
A house has utility power and a proper ground rod. Then they put up a small solar system out back to a small battery bank only. They drive in a separate rod for the solar near the panels. They join the house rod and the solar rod together. They thought it should be done.
What is wrong with their ground design??

Comments

  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    I see no issue. Most structures are required to have a grounding electrode system and the equipment grounding conductor between the two structures will connect the two grounding electrode systems together.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    You bond the different ground rods together if the two separate structures will be sharing AC power... You want a short circuit in either AC power system (grid and solar) to trip the breakers. The 6 AWG able that ties the two system grounds together ensures this happens.

    To ground rods by themselves, have high enough resistance (upwards of 25 Ohms in a "good" grounding system) will not.

    If the shed is solar and the house is grid (separate AC systems that will never "meet" in usage)--You do not have to tie the two grounds together. If, however, the AC backup power from the shed goes to the house (as an example)--Then the two ground should be tied together.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ws9876
    ws9876 Solar Expert Posts: 440 ✭✭✭
    bottom line is any 2nd ground system just for solar and not joined to any AC system should have lightning arrestor.
  • Ethan Brush
    Ethan Brush Solar Expert Posts: 235 ✭✭
    ws9876 wrote: »
    bottom line is any 2nd ground system just for solar and not joined to any AC system should have lightning arrestor.

    I am not sure I would agree with that. I think lightning arrestors/surge protectors are always cheap insurance and I dont see what the second ground system tied or not tied to the AC system would have to do with it.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Do you have a good chance of lightning strikes in your area? Then you probably want to put surge suppressors even on your utility panel/power too. And think about lighting rods on the roof peaks/above the solar panels.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset