Solar Installation

This guide has been created to redo the solar installation at my Home . The previous installation was an adhoc solution, which has been failing multiple causing Inverter Motherboard failures.

Distances and Cable sizing

Use a 4sqmm twisted cable to connect the 2* 24v solar panels connected in series to spd at a distance of 25ft. spd’s ground is connected to earth electrodes via 16sqmm cable at a distance of 5-10ft.

A 4sqmm continues the circuit from spd+MCB(safety switch) to inverter via the MPPT. mppt charge controller allows for use with 24 or 12v system.

The Air Terminal for ligthning arrester with a 16sqmm run both from the air terminal and body of solar panel to electrodes will be added at a later stage.

Wiring Rules

• Use Copper Ring Lugs (thimbles). Crimp the 16sqmm wire into a lug and bolt it to the electrode. A loose connection at the electrode is the #1 reason SPDs fail.
• Drip Loop -a “u” bend to avoid water ingress before the wire enters the building.
• Air gap and induction loops - The 4sqmm DC cables (Panel to SPD) and 16sqmm Earth cable run from roof should be run at a minimal gap of 30 cms and max of 60 cms without touching. Preferably both within their conduits. This avoids accidental creation of giant induction loops.
• Avoid Sharp 90° or “L"Bends and instead Use smooth, sweeping curves for the earth wire. If the wire has a sharp “L” bend, the surge can jump (arc) off the wire into the wall or other cables rather than following the turn.
• DC Conduit: Standard Grey or Orange PVC is fine. Label it “Solar DC” for safety.
• Earth Conduit: Since the 16sqmm wire can get physically hot during a massive strike, ensure its conduit is securely clipped. No metals, PVC pipe is better.

Electrical Components

Sibass (SE-PV-600V).

A 200V rated SPD is even better as long as Response is <25ns. But due to non-availibility, above model is chosen. A “2-Pole” SPD is essentially two protection devices linked together.

• Pole 1: Connects to the Positive DC wire from your panels.
• Pole 2: Connects to the Negative DC wire from your panels.
• The Bottom: Both poles share a common Ground terminal that connects to your 16sqmm copper wire.

Sibass SE-PV63-DC C20

DC MCB rated at C20 to protect 4sqmm wire which melts at 28A. 63A MCB is useless here.

Wiring of Electrical components

The MCB terminals are used as a junction point for Connecting the SPD in parallel:

Positive Side: Take the red wire from the Panel AND a small jumper wire from the SPD (Positive). Put both into the same “Input” hole on top of the MCB. Tighten them together.

Negative Side: Do the same for the black wire and the SPD (Negative) into the other “Input” hole.

The Earth: The bottom of the SPD goes straight to your 16sqmm earth cable.

The Output: Only the wires going to the Inverter/MPPT come out of the bottom of the MCB.

Earthing Components

Back Fill compound

Pacify Earthing Chemical/Back Fill Compound for Electrical Earthing 15 KG Bag ₹999 ASIN: B0GTVL3MT1

Copper Bonded Electrode

Pacify: A pair of Copper Bonded Earthing Electrode 1M 58 mm Diameter The Bonded Rod is Filled with Back Fill Compounds (BFC) Compatible for Up to 5 KW of Load Capacity ₹1,497 ASIN: B0GBY56BQC

Parallel Bonding

If two rods are available use Parallel Bonding. Connect the two electrodes together underground using a 25x3mm GI Strip or a 16sqmm copper wire. This creates a single “Grounding Grid.”

Copper Ring lugs have markings like “16-8” (meaning 16sqmm wire, 8mm bolt hole). Reputable brands for copper lugs in India include Dowells, Jainson, or Comet.

If there is no professional hydraulic crimper, place the wire inside the lug, put it on a solid iron surface (like an anvil or a heavy block), and give it a solid strike with a heavy hammer to “cold-weld” the copper together.

After bolting the lug to your electrode, sealt it by wrapping the entire connection in Vaseline or Grease to keep moisture out.

Steps for Earthing Installation

References:

• solar pump
• solar panel mounting