Earthing and Bonding for Solar PV Systems — PEC 2017 Requirements

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SolarEnergyPH

Solar Guide — Philippines

Article 64 — Day 64

Subject: Earthing and Bonding for Solar PV Systems — PEC 2017 Requirements
Preview: Improper earthing is the hidden defect in most Philippine solar installations. Here's what's required by code.

Earthing and Bonding for Solar PV Systems — PEC 2017 Requirements

Earthing (grounding) is the most under-inspected aspect of solar PV installations in the Philippines. Visible components like panels and inverters are obvious — earthing conductors hidden behind cable trays are not. Yet improper earthing is the root cause of electric shock incidents and equipment failures in solar systems.

Why Solar PV Earthing Is Critical

Shock protection: If a panel frame becomes live due to insulation failure, earthing ensures the fault current flows to ground — not through a person
Equipment protection: Earth fault protection in the inverter depends on a proper earth path
Lightning protection: Earth electrodes provide a low-impedance path for lightning surge energy
PID prevention: Proper system grounding reduces potential-induced degradation in panels

PEC 2017 / NEC Article 690 Earthing Requirements

Component	Requirement	Minimum Size
Panel frames (mounting structure)	All metal parts bonded to equipment ground	6mm² bare copper or green/yellow
Inverter chassis	Equipment grounding conductor to main earth	Sized per output circuit
DC negative (ungrounded systems)	Ground fault detection required (built into inverter)	N/A — inverter function
Earth electrode	Ground rod minimum 2.4m driven at building perimeter	16mm diameter copper-clad steel rod
Main earthing conductor	Connects electrode to MDB and inverter earth bus	Minimum 16mm² copper

Common Earthing Defects in Philippine Installations

Panel frames not bonded — mounting rails floating ungrounded
Earth conductor connected to neutral instead of actual earth electrode
No earth electrode installed — earth wire terminated at water pipe only
Undersized earth conductors (1.5mm² or 2.5mm² used instead of minimum 6mm²)
Corroded earth connections — carbon steel lug on copper conductor

How to Verify Your System's Earthing

Ask your installer to perform an earth continuity test with a multimeter or earth tester. Resistance from any panel frame to the earth electrode should be below 1 ohm. Resistance above 5 ohms indicates a bonding defect requiring correction.

Request an earth continuity test report from installers at solarenergyph.shop.

Engr. Jason Morales — Founder, SolarEnergyPH

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