Combiners, Breakers and Fuses

Protection is chosen on three ratings, and the amps are only one of them. Size the amp rating to the wire it protects. Check the DC voltage rating against your string or bank, since a DC rating is separate from the AC one. Then check the interrupt rating against the current your battery bank can deliver in a short circuit. Combiner boxes join strings before the controller; transition boxes join rooftop wire to the run below. Not sure of a rating? That's one for your electrician.