ᐅ Proper Grounding for Steel Fiber Reinforced Concrete and Waterproof Basement Structures

Hello everyone,

We recently started building and are trying to do as much as possible ourselves.
After we finished the masonry work for the basement, our electrician approached us and said that before we apply the waterproofing on the exterior basement walls, we need to lay a grounding conductor in our excavation pit. This is necessary for lightning protection and the planned photovoltaic system to be installed later. Additionally, this grounding conductor needs to be connected to the existing grounding conductor, which requires drilling through the exterior wall and sealing it afterward (hence before the waterproofing).

We already have a grounding conductor (round rod) installed under the membrane beneath our steel fiber reinforced concrete slab. It has been routed up into our utility room.

Why would I need to essentially install the same grounding conductor again in our excavation pit?

I am getting confused about what is the correct approach here. Could you please explain this to me?

Thank you very much in advance!!!

ck_coke schrieb:

We already have a grounding strap (round bar) beneath the membrane that lies under our steel fiber reinforced concrete slab. This was routed upwards into our technical room.

Who inspected and documented the grounding strap under the slab? As far as I know, your electrician needs to do this before the concrete is poured.

hanse987 schrieb:
Who inspected and documented the grounding strap under the concrete slab? As far as I know, your electrician must do this before the concrete is poured.

That’s how it was done. Our construction company installed the concrete slab and the grounding strap underneath. Their electrician documented and tested everything before the concrete was poured.

Ask your electrician why they want it that way and try to get both electricians to talk to each other.

If I understand correctly, you have grounding under the basement slab. The second electrician now wants grounding outside the foundations around the basement, and you are supposed to do this yourselves?

Knöpfchen schrieb:
If I understand correctly, you have grounding beneath the basement slab. The second electrician now wants grounding outside the foundation around the basement perimeter, and you are supposed to do this yourselves?

Yes, exactly. It doesn’t make sense to me at all, or at least I don’t see the point. He said it’s necessary for external lightning protection and the photovoltaic system.

However, according to our electrician, we only need lightning protection. I don’t think we are required to have it.