Fuses and Circuit Protection

The fitting of adequate fuses or circuit protection in all DC circuits is essential.

These must be big enough to carry the maximum expected current, but not over-sized for the current rating of wire used.

    PV Combiner Boxes and String Fuses

    These are used to allow the parallel connection of several strings of PV modules or to enable large or armoured cables to be connected from the PV array to charge controller or inverter location so minimising voltage & power losses. Since the PV array cannot be switched off these junction boxes must be labelled as 'PV Array Junction Box - Danger, contains live parts during daylight'.
    These boxes can also contain string fuses which provide a means to isolate the PV strings. String fuses must be provided for all arrays formed of N parallel strings, where (N-1) x Isc (module short circuit current) is greater than the module maximum series fuse rating. String fuses are required in both positive and negative legs of the string cabling.
    • PV Combiner Boxes

      PV Combiner Boxes

      2 models available
      From £113.10

      IP66 rated enclosures with standard DIN rail for mounting fuseholders or terminals. Supplied complete with cable glands.

    • PV String Fuse Holders

      PV String Fuse Holders


      Helio DIN rail mounting fuse holders specifically designed for PV & DC applications. Rated at 1000V, 32A DC. Terminals accept up to 10 sq mm flexible cable, or 16 sq mm rigid wire. Pull out carrier to enable easy replacement of fuses.

    • PV String Fuses Type gPV

      PV String Fuses Type gPV

      7 models available
      From £5.50

      These fuses are specifically designed to protect PV modules from reverse currents. Allows for safe circuit interruption under typical low fault conditions produced by PV arrays.

    • PV Combiner Boxes and String Fuses

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    Battery/Inverter Fuses

    Fuses and carriers suitable for protection of cables to inverters.
    • Battery/Inverter Fuse Switch Disconnects

      Battery/Inverter Fuse Switch Disconnects

      11 models available
      From £4.18

      Fuse carriers for NH type fuses, suitable for protecting and isolating cables between the battery and inverter. Integrated handle enabling use as an isolator.

    • Battery/Inverter NH Fuses

      Battery/Inverter NH Fuses

      24 models available
      From £2.72

      NH000, NH1, NH2 & NH3 high capacity fuses suitable for protection of cables from batteries to inverters or charge controllers.

    • Sunny Island Battery/Inverter Breaker

      Sunny Island Battery/Inverter Breaker

      2 models available
      From £356.53

      Double pole circuit breakers. These protect the DC cables between batteries and inverters against overcurrent and short-circuit and allow easy isolation for installation or maintenance of the inverters.

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