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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.
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.

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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:

Grid off ≠ dead

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.

PV can't be zeroed

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.

Battery is high-energy DC

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.

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AC vs DC fault behaviour

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.
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.
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.

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

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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.
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.

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Common mistakes

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.
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.