Q1. What is a Solar Fuse?
A Solar Fuse — also called a PV Fuse or Photovoltaic Fuse — is a fuse-link specifically designed for the protection of photovoltaic string arrays in solar power systems. Unlike standard AC or general-purpose DC fuses, a Solar Fuse must be rated for high-voltage direct current (1000V DC or 1500V DC), certified to IEC 60269-6 (the gPV utilisation category), and capable of interrupting the low-level overcurrents characteristic of reverse current and multi-array faults in PV string arrays. The Lawson LFPV-32 is a 1000V DC Solar Fuse (10x38mm) and the LFPV-35 is a 1500V DC Fuse (10x85mm), both certified to IEC 60269-1 and IEC 60269-6.
Q2. What is a 1500V DC Fuse and when do I need one?
A 1500V DC Fuse is a solar fuse rated for use in photovoltaic systems operating at up to 1500V DC system voltage — the latest generation of high-voltage PV architecture increasingly used in utility-scale and large commercial solar farms. 1500V DC systems allow longer string lengths, fewer combiner boxes, and reduced balance-of-system costs compared to 1000V DC systems, but they require fuse-links specifically rated and tested for 1500V DC arc interruption. The Lawson LFPV-35 (10x85mm) is the correct 1500V DC Fuse for photovoltaic string protection in these high-voltage systems.
Q3. What is the difference between the LFPV-32 and LFPV-35 Solar Fuses?
The LFPV-32 is a 1000V DC Solar Fuse in the standard 10x38mm cylindrical format, suitable for conventional PV string systems up to 1000V DC. The LFPV-35 is a 1500V DC Fuse in a longer 10x85mm format, designed for the latest generation of 1500V DC high-voltage solar installations. The longer body of the LFPV-35 accommodates the greater arc-interruption capability required at 1500V DC. Both are certified gPV Photovoltaic Fuse links to IEC 60269-1 and IEC 60269-6.
Q4. Why can’t I use a standard DC fuse in a solar PV system?
Standard general-purpose DC fuses are not suitable for solar PV string protection because they are not tested for the specific fault conditions of PV systems. PV faults produce characteristically low overcurrents (reverse current, multi-array fault) that a standard DC fuse may not reliably detect and clear. Additionally, standard DC fuses are typically rated at much lower voltages than the 1000V DC or 1500V DC levels found in modern solar string systems. Only a gPV Photovoltaic Fuse certified to IEC 60269-6 provides guaranteed protection against both the low-level fault currents and the high DC voltages of PV arrays.
Q5. What is a gPV fuse?
gPV is the utilisation category defined by IEC 60269-6 for Photovoltaic Fuse links used in the protection of solar PV energy systems. The “g” indicates full-range breaking capacity (protecting against both overloads and short circuits), and “PV” denotes photovoltaic application. A gPV Solar Fuse is specifically tested to interrupt the low overcurrents associated with reverse current and multi-array faults at the full rated DC voltage of the system — either 1000V DC or 1500V DC — providing complete certified protection for PV string arrays.
Q6. What current ratings are available for the LFPV-32 Solar Fuse?
The LFPV-32 PV Fuse (1000V DC, 10x38mm) is available in 13 current ratings: 1A, 2A, 3A, 4A, 5A, 6A, 8A, 10A, 12A, 15A, 20A, 25A, and 32A — covering all standard PV string current protection requirements. The correct current rating for a given PV string is typically determined by the string short-circuit current (Isc) and the maximum reverse current the string can experience under worst-case fault conditions.
Q7. What current ratings are available for the LFPV-35 1500V DC Solar Fuse?
Current rating availability for the LFPV-35 1500V DC Fuse (10x85mm) is available on request — please download the LFPV-35 Product Information Sheet or contact the Lawson Fuses sales team directly for the full current rating schedule and availability for your specific 1500V DC solar installation.
Q8. What fuse holder is compatible with the LFPV-32 10x38mm Solar Fuse?
The LFPV-32 Solar Fuse (10x38mm) is compatible with the Lawson MSC 101 modular cylindrical fuse holder (10×38 Fuse Holder, rated 32A) and other compatible DIN-rail mounted 10x38mm PV fuse holders rated for 1000V DC service. Always ensure the fuse holder is rated for the full 1000V DC system voltage — standard AC-rated fuse holders are not suitable for DC solar applications.
Q9. What fuse holder is compatible with the LFPV-35 1500V DC Fuse?
The LFPV-35 1500V DC Fuse (10x85mm) requires a compatible fuse holder specifically rated for 1500V DC and the 10x85mm fuse body format. Contact the Lawson Fuses sales team for guidance on compatible fuse holder solutions for 1500V DC PV string applications.
Q10. How do I order Lawson LFPV Solar Fuses?
The Lawson LFPV-32 Solar Fuse and LFPV-35 1500V DC Fuse range is available through the Lawson Fuses sales team and their network of authorised sales partners and electrical wholesalers across the UK. Contact Lawson Fuses directly for trade pricing, availability by current rating and voltage, and technical support for your solar PV installation or system design project.