Skip to main content
Good earthing is the difference between protection devices that work and expensive decoration. This page is the overview — exact conductor sizes and terminal torques live on each platform’s installation pages.
For trained/authorized installers only. Earthing errors on a Kent hybrid system can prevent backup operation, defeat all overcurrent and surge protection, and create an undetected live-chassis hazard. Do not cut corners on this work.

​
Protective earth (PE) — first on, last off

Connect the inverter’s PE terminal before any AC or DC wiring. Remove it last when you de-install. This is a universal electrical rule; on a hybrid it matters more because the enclosure sits between three live sources.

Kent M1 — Dual PE is mandatory

Both the AC-connector system ground and the chassis protective-earth point must be connected. Never only one. Use 10 mm² outdoor single-core copper and paint-seal the chassis earth terminal after fitting. The Backup-port PE must also be grounded — backup operation will not work in a grid failure without it.

Kent G3 — External grounding conductor

Connect the external grounding conductor and the heat-sink grounding terminal per the manual figure on the Kent G3 installation page. Copper conductor is recommended. Follow the platform page for cable size.
PV module frames are earthed to the array earth per IS 3043 practice. The PV+ and PV− conductors on these transformerless platforms are not earthed. The platform installation pages carry the specifics for each platform.

​
The earth pit

Measure pit resistance with a proper earth tester at every site. Photograph the reading. Log it on the commissioning checklist. Poor or unmeasurable earth is a stop work condition — fix it before energizing.
Pending Kent validation. [KNB-VAL-14] Kent’s published earth-resistance limit is under confirmation. Until published here: measure and photograph the reading at every site, do not attribute any specific ohm figure to the manual, and escalate poor-soil or high-resistance sites to Kent before energizing.

​
Surge protection (SPD)

Kent requires external Type II SPDs on both the AC and DC sides on Indian sites, regardless of any built-in surge protection in the inverter. The surge and lightning environment on Indian sites demands it.
  • Fit AC-side SPDs at the distribution board.
  • Fit DC-side SPDs in line with the PV string wiring.
  • Check SPD health indicator flags at every service visit — a sacrificed SPD that has not been replaced is an unprotected system.
SPD wiring positions and earth connection points are specified on the platform installation pages. An SPD with a high-impedance earth connection provides no protection — land its earth on a verified, low-impedance earthing point.

​
RCDs

RCD selection is platform-specific and ties into the backup N-E behaviour that is pending OEM confirmation on both platforms.
Residual-current monitoring is built into the Kent M1. External Type A RCDs are supported on the grid side — 100–300 mA is recommended. The backup-side RCD scheme is tied to the N-E behaviour under validation. See [KNB-VAL-04] on the Electrical Basics page.
RCD selection and the backup-side scheme follow the Kent G3 installation page. Until the N-E validation is resolved [KNB-VAL-04], do not add external N-E bonds to manage RCD behaviour in backup mode — record the N-E voltage on the commissioning checklist for Kent review.

​
Common mistakes

Kent M1 has two mandatory PE connections: the AC-connector system ground and the chassis earth terminal. Connecting only one leaves the other path open. The most common consequence is backup mode failing silently in a grid outage — when you need it most.
An SPD with a paint-covered or corroded earth connection cannot discharge a surge impulse quickly enough to protect the equipment. The earth landing point must be clean metal, confirmed low-impedance by measurement.
“The building has earthing” is not a documented earth-resistance reading. Measure, photograph, and log the reading at every site. You are protecting yourself, the customer, and the warranty as much as you are protecting the equipment.