June 3, 20197 yr Hi there. I just want to know what the correct way is to isolate your PV strings from the inverter. Do I break both + and - ? What should be used to isolate the PV strings? Rotary switch, DC circuit breaker, DC fuse holder or a combination?? At this stage I have used rotary switch and fused on both + and - as well as DC circuit breaker om + only with fuse on both + and - again. Any help is welcome. Thanks.
June 4, 20197 yr In a DC system, it's perfectly fine to "break" just one input. + is normally broken, though - can be broken as well. Solar regulations require that we "break" both though. You need to put fuses in for protection, and then an isolator to safely switch disconnect the PV array from the MPPT in case of emergency.
June 4, 20197 yr Author Quote Solar regulations require that we "break" both though. Thanks SilverNadashi, this is exactly what I wanted to know.
June 20, 20197 yr On 2019/06/04 at 8:28 PM, SilverNodashi said: Solar regulations require that we "break" both though. You need to put fuses in for protection, and then an isolator to safely switch disconnect the PV array from the MPPT in case of emergency. Some MPPT’s like Microcare have built in breakers. Is this acceptable with only fuses, or do they require a separate breaker besides the one in the MPPT?
June 21, 20197 yr Good question. I have fuses and use the mppt breakers. Interested in the experts opinion!
June 21, 20197 yr 1 hour ago, DeepBass9 said: Good question. I have fuses and use the mppt breakers. Interested in the experts opinion! I recently learnt that I don't need fuses, can just use the NoArk breakers, right sized off course.
June 21, 20197 yr 18 hours ago, Solaris said: Some MPPT’s like Microcare have built in breakers. Is this acceptable with only fuses, or do they require a separate breaker besides the one in the MPPT? The Microcare MPPT I have don't have DC-rated breakers in it. Whether the breakers actually have a DC-rating, that I do not know. Also don't know if newer MPPTs rectified this little oversight (mine is from 2013). I rather doubt that the breakers are sufficient. I can't find any info on it, they are "Crabtree SB2" units with a 230VAC rating indicated. I see the newer ones have Chint breakers. I know some of them (Chint ones) have DC ratings.
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