I have a question that I haven’t been able to get a relevant answer to so far when I've queried a few content creators on YouTube in response to their videos on fusing. It concerns 3 different branch circuits that are switched following their connection to a 12v fuse block. I’m building a DIY power station and would like to have some small fans for ventilation inside the box (that holds a 12v 230ah LiFePO4 battery and Victron 100|50 MPPT solar charge controller). I would also like to run several switched USB outlets and similarly switched LED light strips. The USB ports and the fans have various low amperage draws and very small wires connected to each component.
My question relates to whether the various small circuit components should be individually fused following their switch since the wires are so small and also spliced as they are very short. Are the inline fuses shown in the attached diagram redundant or would they help protect the individual small wires?
I guess I’m wondering if for example, the wires from 4 small switched components drawing under 1 amp each would be protected by a 5amp fuse in the main fuse block or would it be better to have each component wire protected by an individual 1 amp fuse following the switch with the entire ganged circuit protected by a 5 amp fuse in the fuse block as the diagram illustrates.
Bottom line: Do I need a new fuse every time wire size decreases in a circuit following a connection?
I haven’t labeled any of the wire or fuse specs in the diagram as my question is more of a generic one regarding fusing whenever a connection includes a decrease in wire size. I’ll be using charts and tables (like those published online by Blue Sea Systems, Ancor, etc.) to determine proper wire sizes and fuses. I also note that this portion of the diagram only addresses the smaller 12v components, I’ll also have a few connections for other SB50 Anderson ports for ACDC & DCDC chargers and solar panels protected by proper DC breakers wired directly to the bus bars. I originally planned to include an AC inverter but later decided to keep everything in this project strictly 12v DC in case anyone wonders about the truncated connections shown coming off the fuse block and bus bars. Also not shown is an MRBF on the battery positive post and a t-fuse following a main cutoff switch as well. (So, the following diagram is a detail and not the entire layout.)
I assume it is OK to daisy chain all the negative leads from the various components and switches as the circuit connects to the fuse block side. If that is incorrect, please advise. Thanks.
My question relates to whether the various small circuit components should be individually fused following their switch since the wires are so small and also spliced as they are very short. Are the inline fuses shown in the attached diagram redundant or would they help protect the individual small wires?
I guess I’m wondering if for example, the wires from 4 small switched components drawing under 1 amp each would be protected by a 5amp fuse in the main fuse block or would it be better to have each component wire protected by an individual 1 amp fuse following the switch with the entire ganged circuit protected by a 5 amp fuse in the fuse block as the diagram illustrates.
Bottom line: Do I need a new fuse every time wire size decreases in a circuit following a connection?
I haven’t labeled any of the wire or fuse specs in the diagram as my question is more of a generic one regarding fusing whenever a connection includes a decrease in wire size. I’ll be using charts and tables (like those published online by Blue Sea Systems, Ancor, etc.) to determine proper wire sizes and fuses. I also note that this portion of the diagram only addresses the smaller 12v components, I’ll also have a few connections for other SB50 Anderson ports for ACDC & DCDC chargers and solar panels protected by proper DC breakers wired directly to the bus bars. I originally planned to include an AC inverter but later decided to keep everything in this project strictly 12v DC in case anyone wonders about the truncated connections shown coming off the fuse block and bus bars. Also not shown is an MRBF on the battery positive post and a t-fuse following a main cutoff switch as well. (So, the following diagram is a detail and not the entire layout.)
I assume it is OK to daisy chain all the negative leads from the various components and switches as the circuit connects to the fuse block side. If that is incorrect, please advise. Thanks.
