LMB5-40 1P+N MCB 18mm 40A Miniature Circuit Breaker

Product Overview

LMB5-40 series miniature circuit breaker (MCB) is a modular DIN rail mounted protection device, designed for AC 50Hz, 230V low voltage distribution systems. It protects electrical wiring and loads against overload and short circuit faults. The C-curve characteristic is suitable for lighting, socket and general inductive/resistive loads. Compact 1P+N design saves cabinet space, widely used in domestic, commercial and small industrial distribution boxes.

Key Features

✅ Dual protection: Overload protection & instantaneous short-circuit protection
✅ C curve trip characteristic for common household & light commercial loads
✅ 3kA rated short-circuit breaking capacity
✅ Compact 1P+N modular structure
✅ High-strength flame-retardant plastic housing, heat & aging resistant
✅ Clear ON/OFF operating handle for visible circuit status
✅ Simple installation on standard 35mm DIN rail

Main Functions

1. Overload Protection When continuous load current exceeds rated value, the MCB trips automatically to prevent cable overheating and fire hazards.
2. Short Circuit Protection Instant tripping under short circuit fault, rapidly cuts off fault current to protect cables and downstream equipment.
3. Circuit Isolation & Switch Control Manual ON/OFF operation for power isolation during equipment inspection and maintenance.

Technical Specifications

Application

• Residential consumer unit lighting & socket circuits
• Apartment, villa power distribution
• Shop, office low-voltage distribution
• Small control cabinets & auxiliary equipment protection
• PV AC side secondary protection

Installation Instructions

⚠️ Installation must be completed by qualified electrician. Cut off power supply before wiring!

1. Clip the MCB onto the 35mm standard DIN rail inside distribution box.
2. Top terminals: power incoming; bottom terminals: connect to load.
3. Tighten terminal screws firmly, ensure no bare copper exposed.
4. After wiring, test handle ON/OFF action to confirm normal operation.
5. IP20 indoor use only, not for outdoor exposed installation.

Operation Guide

• Handle UP = ON, circuit energized
• Handle DOWN = OFF, circuit disconnected
• If automatic tripping occurs, inspect the circuit for overload or short-circuit fault before re-closing. Do NOT force reset repeatedly.

Safety Warnings

1. For AC low voltage system only, NOT applicable for DC circuits.
2. Installation and maintenance must be performed by certified electricians.
3. Do not operate beyond rated voltage and rated current.
4. Stop using immediately if housing cracks, burns or emits abnormal odor.
5. This MCB only provides overload and short-circuit protection. It has NO leakage protection function. Use RCBO/RCCB if earth leakage protection is needed.

Packing List

LVMA LMB5-40 Miniature Circuit Breaker ×1pc, Instruction Manual ×1pc

Warranty

24 months warranty from manufacturing date under proper installation and normal working conditions. Warranty becomes void for man-made damage, overload burnout, unauthorized disassembly or operation under harsh environments.