What Is the Difference Between gG, gR, aM, aR, gPV, gBat Fuses?
Fuse classes (gG, gR, aM, aR, gPV, gBat) define protection targets, speed, breaking capacity and applications. They follow IEC 60269-4/-7 standards. Choosing the right class avoids burnout, fire, and equipment damage.
1. gG Fuse (General Purpose, Full-Range)
- Class: gG (general, full-range)
- Speed: Slow / standard, non-fast
- Protection: Wires, cables, motors, transformers, general AC circuits
- Range: Overload + short circuit (full-range)
- Current: 2A–630A, 500V/690V AC
- Use: Industrial distribution, home appliances, general machinery
- I²t: High (not for semiconductors)
2. gR Fuse (Semiconductor, Full-Range)
- Class: gR (full-range semiconductor)
- Speed: Fast, faster than gG
- Protection: Semiconductors + cables (dual)
- Range: Overload + short circuit
- Current: 10A–400A, 690V AC/DC
- Use: Drives, inverters, general power electronics
- I²t: Medium-low (better for semis)
3. aM Fuse (Motor, Partial-Range)
- Class: aM (motor, partial-range)
- Speed: Slow, time-delay for motor inrush
- Protection: Motor short circuits only (no overload)
- Range: Short circuit only (partial-range)
- Current: 10A–630A, 690V AC
- Use: Motors, pumps, fans, compressors
- I²t: High (tolerates startup surge)
4. aR Fuse (Semiconductor, Ultra-Fast, Partial-Range)
- Class: aR (semiconductor, ultra-fast)
- Speed: Ultra-fast (≤10ms), fastest common class
- Protection: IGBT, MOSFET, diode, thyristor
- Range: Short circuit only (partial-range)
- Current: 10A–3000A, 500V–1500V DC
- Use: EV, ESS, solar, inverters, converters
- I²t: Ultra-low (critical for semiconductors)
5. gPV Fuse (Photovoltaic, Full-Range DC)
- Class: gPV (photovoltaic, DC full-range)
- Speed: Fast DC
- Protection: Solar PV modules, combiner boxes
- Range: Overload + short circuit (DC)
- Current: 1A–630A, 1000V/1500V DC
- Use: Solar panels, PV inverters, DC combiner boxes
- I²t: Low, DC arc-extinguishing design
6. gBat Fuse (Battery Energy Storage, Full-Range DC)
- Class: gBat (battery, ESS full-range)
- Speed: Fast, optimized for battery DC
- Protection: Battery packs, BMS, ESS systems
- Range: Overload + short circuit (DC)
- Current: 10A–3000A, 500V–1500V DC
- Use: Energy storage (BESS), EV battery packs
- I²t: Very low, prevents thermal runaway
Quick Comparison Table
- gG: General AC, slow, wires/motors, high I²t
- gR: Semiconductor AC/DC, fast, dual protection
- aM: Motor AC, time-delay, short circuit only
- aR: Semiconductor DC, ultra-fast, IGBT, lowest I²t
- gPV: Solar DC, fast, PV modules, 1500V DC
- gBat: Battery/ESS DC, fast, prevents thermal runaway
FAQ
What’s the difference between aR and gR?
aR is ultra-fast, short-circuit only for semiconductors; gR is fast, full-range (overload + short) for semiconductors + cables.
Can gG replace aR?
No. gG has high I²t and slow speed; it will burn IGBTs.
What’s gBat fuse for?
gBat is for battery energy storage (BESS), prevents thermal runaway in DC battery packs.
gPV vs gBat?
gPV = solar PV DC; gBat = battery ESS DC (higher current, anti-thermal runaway).