Electrical
Lightning and Surge Protection for Commercial Solar Systems
A commercial solar array is a large, exposed electrical asset, which makes surge and lightning protection a core part of good design rather than an afterthought. Getting it right protects your inverters, your switchboard and the equipment downstream.
Why commercial solar is exposed to surges
A rooftop array covers a large area and sits in one of the most exposed positions on your site. That footprint, combined with long DC cable runs between panels and inverters, makes a solar system a natural pathway for transient voltage spikes.
Surges don't only come from direct lightning strikes. Nearby strikes, switching events on the grid and faults elsewhere on the network can all push damaging transients into your system. The inverter is usually the most vulnerable and most expensive component in the firing line.
- Large roof footprint increases exposure to nearby lightning activity
- Long DC strings act as pathways for induced voltage spikes
- Grid switching and network faults create transients from the mains side
- Inverters and control electronics are the most sensitive to damage
Direct strikes vs induced surges
It helps to separate the two threats. A direct lightning strike delivers enormous energy and is managed with a lightning protection system - air terminals, down conductors and a low-impedance path to earth that keeps that energy away from your equipment.
Induced surges are far more common. These are the voltage spikes that couple into your wiring from a strike nearby or from grid events. You manage them with surge protection devices (SPDs) installed at the right points, which clamp the transient and divert it safely to earth before it reaches sensitive gear.
Surge protection devices and where they go
Effective protection is layered. SPDs are placed on both the DC and AC sides of the system so transients are intercepted before they can travel through to the inverter or into the building's switchboard.
The right type and rating for each location depends on your site, the exposure level and the equipment being protected. This is determined during design and is part of a compliant installation, not an optional extra.
- DC-side SPDs to protect the inverter from spikes travelling up the strings
- AC-side SPDs at the inverter output and main switchboard
- Correct device type matched to the exposure and location
- Coordination between SPDs so each stage does its job
Earthing and equipotential bonding
Surge protection is only as good as the earth it discharges into. A properly designed earthing system gives transients a low-resistance path away from your equipment, and equipotential bonding keeps metal parts of the array and structure at the same potential so dangerous voltage differences don't build up.
On larger commercial installs - the kind that scale up toward the MW range - earthing needs careful attention across the full roof and cabling layout. Done well, it protects both your equipment and the people working on site.
Protecting batteries and smart energy systems
Batteries and energy-arbitrage controllers add valuable, sensitive electronics to the mix. A system that charges when power is cheap and discharges when it's dear is only delivering value while it's running, so protecting that hardware from surges is directly tied to your returns.
We build surge and earthing considerations into battery and control system design from the start, so the equipment managing your energy costs is shielded from the transients that could knock it offline.
Standards, maintenance and getting it checked
Surge protection and earthing are covered by Australian wiring and installation standards, and ATI's CEC and SAA accredited, in-house team builds compliant protection into every commercial job - no subcontractors handling the critical bits.
SPDs can wear out over their life, often after absorbing surges you never noticed, so periodic inspection matters. If you're not sure your existing system is properly protected, or you're planning a new install, a site review is the practical next step. We'll assess your exposure, your existing earthing and the right level of protection for your site - reach out when you're ready.
Surge protection is cheap insurance for expensive gear - specify it properly at design stage, not after a strike takes out your inverter.
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