> ## 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.

# Electrical Safety Basics for Kent New Energy Hybrids

> The hybrid electrical model that keeps you safe: one box, three sources, DC arc behavior, the 0.5 A rule, backfeed, and the backup N-E validation warning.

If you learned on grid-tie or plain UPS systems, hybrids break two of your habits. This page resets them before you go near a Kent unit.

<Warning>
  **For trained/authorized installers only.** Understanding these concepts is a prerequisite for safe work on Kent M1 and Kent G3 systems — not a substitute for hands-on training and authorization.
</Warning>

## One box, three sources

A Kent hybrid inverter joins **PV DC**, **battery DC**, and **grid AC** inside one enclosure, and feeds a separate **Backup port** that stays live during a grid outage. That single enclosure is the source of most field confusion — here is what it means in practice:

<CardGroup cols={3}>
  <Card title="Grid off ≠ dead" icon="triangle-exclamation">
    Opening the grid breaker cuts grid AC. The Backup port keeps making AC from battery and PV — that is its job. Isolate all three sources, not just the grid.
  </Card>

  <Card title="PV can't be zeroed" icon="sun">
    Any daylight means string voltage at the PV terminals. You can isolate PV with the DC switch; you cannot make it truly zero while the sun is up. Work accordingly.
  </Card>

  <Card title="Battery is high-energy DC" icon="battery-full">
    51.2 V will not usually shock through dry skin. Hundreds of amps through a dropped spanner is a welding accident. Treat battery DC with the same respect as high-voltage AC work.
  </Card>
</CardGroup>

## AC vs DC fault behaviour

<Accordion title="Why DC arcs do not self-extinguish">
  AC arcs self-extinguish at every zero-crossing — 50 times per second on a 50 Hz system. DC has no zero-crossing. A DC arc sustains until the gap becomes large enough to extinguish the plasma or the source is removed. This is why you never part a DC connector under load and why the Kent G3 manual requires string current **below 0.5 A** before its DC switch is operated.
</Accordion>

<Accordion title="Reverse polarity on DC is not a 'phase swap'">
  Swapping L and N on AC causes a nuisance trip. Reversing polarity on DC can destroy inverter electronics instantly. Before energizing any string or battery run, meter-verify polarity. Every time, no exceptions.
</Accordion>

<Info>
  **The 0.5 A rule for Kent G3:** Use a DC-capable clamp ammeter to confirm string current is below 0.5 A before operating the DC switch. An AC-only clamp meter reads garbage on DC current — it cannot make this check.
</Info>

## Backfeed and the Backup port

The Grid port and the Backup port must never be swapped. Grid supply lands on the **Grid port**; essential loads connect to the **Backup port**. If grid voltage arrives on the Backup port, it destroys the internal transfer stage.

<Warning>
  Verify Grid and Backup port identification before energizing. Label both ports clearly during installation so the next technician on site cannot confuse them.
</Warning>

## Neutral and earth in an outage

In backup operation the neutral-earth relationship is managed by the inverter platform — not by external wiring. Do not improvise N-E bonds to stop an RCD tripping during an outage test. That action has real consequences for protection, and it is a Kent-guided procedure pending OEM written confirmation.

<Warning>
  **Pending Kent validation — do not configure in the field.** \[KNB-VAL-04]
  Backup N-E bond-relay behaviour and the approved RCD scheme for both platforms are under written confirmation from the OEM. Until published here: never add external N-E bonds, and record the N-E voltage during the outage test on the commissioning checklist for Kent review.
</Warning>

## Common mistakes

<Accordion title="Testing 'dead' with a neon screwdriver">
  A neon screwdriver confirms AC presence above roughly 100 V on one conductor. It tells you nothing about DC voltage, conductor-to-earth AC, or voltage below its threshold. Use a rated CAT III multimeter, prove it works on a known live source first, then verify dead on the conductors you are about to touch.
</Accordion>

<Accordion title="Assuming the RCD protects the DC side">
  Standard Type A and Type AC RCDs are AC-sensing devices. DC ground faults and arc-faults on the PV or battery side require the system's own built-in protection to be working correctly. This is why earthing continuity and SPD health checks are part of every commissioning and service visit.
</Accordion>

## Related pages

* [Isolation & Shutdown](/safety/isolation-and-shutdown)
* [Earthing & Protection Overview](/safety/earthing-and-protection)
* [Safety First](/safety/safety-first)