Solar Disconnects & Transfer Switches

How to Choose

Size on current and voltage, with margin. DC breakers and disconnects must be rated for DC — an AC-rated breaker will not interrupt a DC arc and is a fire risk, not merely a code violation. Transfer switches are chosen by service size, most commonly 200A for a US home, and by whether you need automatic or manual operation: automatic costs more but means the house recovers without anyone being home. Busbars are sized by total current, and it is worth buying more capacity than you need now so the next battery does not force a rebuild.

Key Specifications Explained

• DC rating: Breakers and disconnects must be DC-rated, not AC-rated
• Transfer switch: 200A is standard for a US residential service; automatic or manual
• Busbars: Rated up to 600A; size for future capacity, not today's load
• Load centers: Pre-wired balance of system saves a day of enclosure fabrication
• Listing: UL 67, UL 489 and UL 1008 depending on device class

Brands We Carry

EG4 Electronics, Eaton, Growatt, Tigo Energy, OutBack Power, MidNite Solar, Schneider Electric and IMO Solar.

Frequently Asked Questions

Can I use an AC breaker on the DC side?

No. DC arcs do not self-extinguish at a zero crossing the way AC does. Use DC-rated devices on every DC circuit, without exception.

Automatic or manual transfer switch?

Automatic if the house needs to recover with nobody home — refrigeration, sump pumps, medical equipment. Manual is cheaper and fine for a cabin.

What size busbar?

Total the maximum current of everything landing on it, then step up a size. Busbars are cheap; rebuilding a battery enclosure is not.

Related Categories

• Solar Combiner & Junction Boxes
• Rapid Shutdown Devices
• Solar Surge & EMP Protection
• Solar Cables & Connectors