> ## Documentation Index
> Fetch the complete documentation index at: https://learning.kent.co.in/llms.txt
> Use this file to discover all available pages before exploring further.

# Kent M1 Earthing and RCD — Dual PE and Protection

> Both PE points are mandatory on every Kent M1, backup PE is non-negotiable, and the correct RCD ratings for the grid and backup sides.

The Kent M1 has two protective-earth points and both are mandatory. Skipping either one is not a shortcut — it creates shock risk and, on the backup port, causes the inverter to stop supplying backup loads during a grid failure. Complete earthing before you touch any other wiring on this platform.

<Warning>
  **For trained and authorised installers only.** Earthing errors on this platform cause shock risk and backup failure — not just alarms.
</Warning>

## Before you start

* Earthing is completed **before** PV, battery, or AC wiring — no exceptions.
* Measure and photograph the earth pit per [Earthing & Protection](/safety/earthing-and-protection). Escalate poor soil resistance before energising.

## Dual PE — never only one

You must connect both protective-earth points on every Kent M1 installation:

<Steps>
  <Step title="System ground in the AC output connector">
    Land the PE conductor in the **PE position of the GRID connector**. This is the system ground path.
  </Step>

  <Step title="Chassis protective earth">
    Connect the chassis earth terminal using an **M4×10 screw** torqued to **1.2 N·m**. Use **10 mm² outdoor single-core copper** cable. After fitting, **paint the chassis earth terminal** for corrosion resistance.
  </Step>
</Steps>

<Warning>
  Connecting only one PE point is forbidden. With multiple inverters on site, every unit gets its own independent earth connection — never daisy-chain chassis earths.
</Warning>

<Tip>
  Use outdoor-rated, UV-stabilised green/yellow single-core copper at 10 mm². The chassis terminal screw is M4×10 — do not substitute a longer or shorter fastener.
</Tip>

## Backup-port PE

The **BACKUP port PE must be grounded or backup will not operate during a grid failure.** This is the single most expensive earth wire to forget — the customer discovers it only during their first power cut, which is exactly the wrong moment.

<Warning>
  Do not leave the backup PE floating, even temporarily. The BACKUP port PE is a functional requirement, not just a safety requirement.
</Warning>

## Residual-current protection

The inverter has **built-in residual-current detection** and disconnects from the grid automatically when leakage exceeds its internal threshold.

External RCDs are supported and recommended:

| Side        | RCD type | Rating                   |
| ----------- | -------- | ------------------------ |
| Grid side   | Type A   | 100–300 mA (recommended) |
| Backup side | Type A   | 30 mA                    |

<Warning>
  **Pending Kent validation — do not configure in the field.** \[KNB-VAL-04]
  Written confirmation of the backup N-E bond-relay behaviour and the approved RCD scheme is in progress. Until published here: follow the Kent N-E test in the commissioning checklist and never improvise an external N-E bond at the backup panel.
</Warning>

<Info>
  The Advanced menu contains an **NPE Relay Check** and an **NPE voltage protection threshold** — evidence of internal N-E supervision. Leave both at factory state unless a Kent parameter sheet instructs otherwise.
</Info>

## Common mistakes

* Landing one PE point and calling it done — dual PE is a hard rule on this platform.
* Leaving the backup PE floating because "backup worked fine on grid" — it fails exactly when the grid fails.
* Improvised N-E bonding in the backup panel to stop RCD trips. \[KNB-VAL-04]
* Using undersized or indoor-rated earth cable — 10 mm² outdoor single-core copper is the specified conductor.

## When to escalate

Escalate to Kent New Energy service only — through your registered Kent partner channel or the Kent service desk details on your work order. Do not contact any third-party or component-manufacturer support line for a Kent-branded system: tickets outside the Kent channel are not tracked, not covered, and can void warranty handling.

## Related pages

* [Kent M1 Installation](/m1/installation)
* [Kent M1 AC Wiring](/m1/ac-wiring)
* [Kent M1 Commissioning](/m1/commissioning)