Earthing for shed

davidknowles

New member
Joined
Nov 12, 2019
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Hi guys, would be good to get some thoughts from the group on this earthing situation, probably not uncommon.

I have chatted to several electricians and got several different answers lol (no surprises)

My setup (not finished yet)


  • House with full main electricity, standard breaker box with earthing.
  • Shed, steel-framedon slab(1.5m from the house)
  1. Shed has mains feed from house supplying PIP-5048MK as backup.
  2. 3kw of 250w panels, in 4p3s config for 33A 92V of supply.
  3. Panels are earthedto the roof (and steel studs) then to anearth peg.


Currently, there is not going to be feedback to the house, and the setup is just for the shed to run freezers and servers.
But later down the track, I might get an electrician to feedback to the house breakout box (I have a second conduit in place if I choose to go this route)

Now with regards to earthing, one electrician said I can earth the inverter and shed breaker box on the same earth pike as the shed and the panels.
Second electrician said I should have a second earthing pike for the inverter and shed breakout box, for additional equipment protection incase of a lighting strike.

Now from my early days as an apprentice 18 years ago (before I moved on to other things and pulled the pin lol), I remember that sometimes multiple earthing can cause issues, and for closely connected wiring you should share the same earth pike as several can cause a loop impedance.

So it brings to question when I connect up the house to the PIP, later on, I should probably run an earth back to the house earth.

What have others done in this situation? the goal is safety over everything, human then equipment.
 
The 1st electrician is right for the grounding of the panels, shed, inverter, etc.
The 2nd electrician is right IF you installed lightning rods - they should be separately grounded.
You would need to go with electrician 1's method as the earthing protection requirement for panels is focused on peoples safety & this is about equal potential bonding.
 
I'm interested in this as I'm in the final stages of a backyard pv array. I have the framework + panels all bonded and routed with a 6AWG wire to ground busbar of the outdoor combiner box (left side of picture). The lightning arresters for the combiner boxarriving this week. The wiring into the house includes aground wire between the combiner box and the house ground - so 'the array' is ground to the house ground. I have read about the dangers of using additional grounding rods instead of relying on house ground.

image_vagnxo.jpg
.

Any comments on grounding appreciated.

I plan to build a shed under the right hand side of the array at some point and it could very well be a metal kit with power which will put me in a similar situation :)
 
Redpacket said:
The 1st electrician is right for the grounding of the panels, shed, inverter, etc.
The 2nd electrician is right IF you installed lightning rods - they should be separately grounded.
You would need to go with electrician 1's method as the earthing protection requirement for panels is focused on peoples safety & this is about equal potential bonding.
Thanks, Yeah the first electriction seemed more switched on too (no pun lol)
 
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