BG Bi-Directional MCB B Curve Single Pole 20A CUMB20

BG CUMB20 — 20A B Curve Single-Pole Bidirectional MCB (6kA, 1 Module)

The BG CUMB20 is a 20A B-curve, single-pole bidirectional MCB designed for dependable overload and short-circuit protection on domestic and light-commercial circuits. With certified bidirectional operation, it provides safe tripping even where current may flow from either direction—ideal for systems incorporating solar PV, battery storage or other back-feed capable technologies.

Its slim 17.85mm module width ensures a clean, space-efficient fit within all BG consumer units and standard 35mm DIN-rail enclosures.

Reliable Protection for General-Purpose Circuits

The B-curve tripping profile ensures fast response on low-inrush circuits commonly found in domestic installations. With a 6kA breaking capacity, the CUMB20 provides robust short-circuit protection for:

General radial circuits

Socket circuits

Small appliance loads

Utility and lighting sub-circuits

Built to support quick installation and long-term durability, the CUMB20 includes:

Positive contact status indication

PZ2 screw terminals for secure connections

Terminal capacity up to 16mm² (10–32A models)

Operating temperature –25°C to +40°C

Endurance of 4,000 electrical and 10,000 mechanical operations

This ensures confidence during installation and reliability throughout the device’s working life.

Key Features of the BG Bi-Directional MCB 20A Include:

• 20A B-Curve Single-Pole Bidirectional MCB
• Suitable for PV, Battery Storage & Back-Feed Installations
• 6kA Breaking Capacity for Dependable Fault Protection
• Compact 1-Module (17.85mm) Width
• Positive Contact Status Indication
• PZ2 Screw Terminals with Up to 16mm² Cable Capacity
• Operating Temperature Range: -25°C to +40°C
• Durable Mechanism: 4,000 Electrical & 10,000 Mechanical Operations
• Complies with IEC/EN 60898 Standards

View all BG MCBs

If you just need some help, would like to take advantage of our Price Promise or perhaps have a large order to place give our team of professionals a call on 0203 994 5470, drop us an email at sales@electricpoint.com or use our Contact Form.