These are copper busbars (sometimes called busbar strips or earth/neutral busbars depending on use).
What they look like
What they are used for
1. Power distribution
A busbar carries large electrical current and distributes it to different circuits.
Instead of many cables, one solid copper bar spreads power.
2. Earthing (grounding)
Often used as an earth bar where all earth wires connect.
That’s why you see it near green/yellow cables (earth wires).
3. Connecting heavy equipment
Used in:
Distribution boards (DB)
Main panels
Generator connections
Solar systems
Why it has holes
The holes are for:
Bolting cable lugs
Fixing connections securely
Makes it easy to connect multiple cables neatly
Why copper is used
Very good conductor
Handles high current safely
Long-lasting and doesn’t rust