How to Choose the Right MCB Rating for Your Home or Office
A Simple Guide to Selecting MCB Ampere Rating & Trip Curve
Choosing the wrong MCB rating is one of the most common electrical mistakes in homes and offices. An undersized MCB trips too frequently causing inconvenience. An oversized MCB does not trip when it should, leaving your wiring dangerously unprotected. This guide from JSR Group helps you select the right MCB for every circuit.
Step 1 — Understand MCB Ratings
MCBs are rated in Amperes (A). Common residential ratings are 6A, 10A, 16A, 20A, 25A, 32A, 40A, and 63A. The rating indicates the maximum continuous current the MCB allows before tripping.
Step 2 — Match MCB to Wire Size
| Wire Size | Max. Current | MCB Rating | Typical Use |
|---|---|---|---|
| 1 sqmm | 10A | 6A | Lights, fans |
| 1.5 sqmm | 15A | 10A | Light + small sockets |
| 2.5 sqmm | 20A | 16A | General power sockets |
| 4 sqmm | 27A | 20A | AC, geyser circuits |
| 6 sqmm | 35A | 32A | Main sub-panel incoming |
B, C, D Curve — What Does It Mean?
B Curve — trips at 3–5× rated current. Best for resistive loads like geysers and heaters.
C Curve — trips at 5–10× rated current. Best for general use — motors, AC units, mixed loads. Most common choice.
D Curve — trips at 10–20× rated current. For high inrush loads like transformers and large motors.
Buy Polycab MCBs in Gurgaon & Delhi NCR
+91-9311945078 | All ratings and curves in stock | JSR Group, Gurgaon
