Solar fuses and breakers must be selected for the circuit’s voltage, available fault current, conductor limits and equipment instructions. There is no universal fuse size for every portable solar setup.
Editorial correction: Earlier versions included unsupported testing, experience or performance claims. This research guide replaces those claims. Examples below are calculations, not measurements made by Wild Smart Gear.
Define the circuit first
Distinguish panel-to-charge-controller wiring, battery charging paths and inverter/load wiring. Battery circuits can supply very different fault currents from a PV source. Protection for one part does not replace protection elsewhere.
Identify panel series/parallel arrangement, maximum system voltage, panel short-circuit current, equipment ratings and applicable electrical requirements.
Check the protection device
- DC voltage rating suitable for the full circuit voltage.
- Interrupting capacity appropriate to the available fault current.
- Current/time characteristics specified for the equipment and conductors.
- Correct polarity where required and suitability for the environment.
- Manufacturer-approved holders, terminations and placement.
An AC-only breaker is not automatically suitable for DC interruption. Do not choose a fuse simply from panel watts divided by nominal battery voltage.
Portable stations versus custom installations
Use factory-supported cables and panel configurations for a portable station. External system modifications, parallel branches or custom battery banks may require an installation design; a built-in controller does not certify improvised wiring.
Follow manuals and have an appropriately qualified installer determine conductor protection and code compliance. This guide does not provide a one-size wiring or fuse table.
When a fuse opens
An opened fuse can indicate a fault or unsupported arrangement. Isolate the system according to its instructions and investigate before replacing it with the prescribed type. Never fit a larger fuse or bypass it to maintain charging.