Rooftop solar is booming across India, but many home systems are installed with little or no protection on the DC side, which is the wiring between your panels and your inverter. That side carries high DC voltage all day, so the right protection keeps your panels, inverter and home safe from faults, overloads and lightning surges.
Every well-built system uses three devices on the DC side: a PV fuse, a DC MCB and a DC surge protector (SPD). Here's what each one does and how to choose it.
1. PV fuse: protects each panel string
A PV fuse sits on each string of panels, before the combiner box or DCDB. If one string develops a fault, the fuse blows and stops current from other strings flowing back into it.
How to choose: the fuse holder's voltage rating should be above your string's maximum voltage, and the fuse link rating should follow your panel datasheet (look for "maximum series fuse rating").
Our pick: the DROSS ZYPV-32X Solar PV Fuse Holder, rated 32A and 1000V DC, which takes standard 10×38mm PV fuse links and mounts on a DIN rail.
2. DC MCB: switches off and protects the circuit
A DC MCB protects against overload and short circuits, and lets you safely isolate the DC circuit for maintenance. It's used on strings, in the DCDB and at the inverter input.
How to choose:
- Voltage: your string's maximum open-circuit voltage (Voc) should stay below the MCB's rating.
- Current: pick a rating about 125% of your normal circuit current, and never above your cable's rating.
- 1 Pole or 2 Pole: a 2 Pole MCB switches off both positive and negative lines together for full isolation. A 1 Pole switches one line.
Our picks: the DROSS DC MCB 63A 2 Pole 600V for full isolation, the DC MCB 63A 1 Pole 600V when you only need to switch one line, and the DC MCB 125A 1 Pole for higher-current battery-to-inverter circuits.
3. DC surge protector (SPD): guards against lightning
Panels sit on your roof, exposed to lightning and monsoon storms. A nearby strike can send a voltage surge down the DC cables and damage your inverter. A DC SPD diverts that surge safely to earth.
How to choose: use a Type 2 DC SPD rated above your system's maximum DC voltage, installed at the DCDB or the inverter's DC input, and make sure it has a proper earth connection.
Our pick: the DROSS DC Surge Protector for Solar PV, 600V DC, or the DROSS SPD-40 with fuse set.
Quick reference
| Where in your system | What to use |
|---|---|
| Each panel string, before the combiner box or DCDB | ZYPV-32X fuse holder (1000V DC, 32A) with a 10×38mm PV fuse link |
| Isolating a DC circuit (string, DCDB, inverter input) | DC MCB 63A, 1 Pole or 2 Pole (600V DC) |
| Battery to inverter (higher current) | DC MCB 125A, 1 Pole |
| Surge and lightning protection at the DCDB or inverter input | DC SPD (Type 2, 600V DC) |
Want everything in one box?
The DROSS Solar Protection Combo includes a DC SPD, a DC MCB 63A 2 Pole and a ZYPV-32X fuse holder, so you have the core DC protection for a home system sorted in one order.
Not sure what your system needs?
WhatsApp us on +91 99928 08001 with your panel wattage, the number of panels in series, and your inverter or battery voltage, and we'll suggest the right protection. Installers and electricians can ask about bulk rates too.
Solar DC wiring carries high voltage. Installation should always be done by a qualified electrician.