EXORA MCB 40A FP 415V AC 10kA B Curve | L&T – BB40400B

Name: L&T Exora 40A 415V MCB, B Curve, 10kA - BB40400B
Brand: Lauritz Knudsen (L&T)
SKU: BB40400B
Price: 1634.00 INR
Availability: OutOfStock

SKU: BB40400B

Original price was: ₹3,800.00.Current price is: ₹1,634.00. Excl. GST

Out of stock

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Looking for the EXORA MCB 40A FP 415V AC 10kA B Curve | L&T? This genuine BB40400B miniature circuit breaker (mcb) is built for reliable circuit protection and isolation, combining proven reliability with full compliance to applicable IEC/IS standards. Key ratings include 40 A, 415V AC, 4 Poles. Order part number BB40400B from myelectric.in — a trusted BB40400B supplier offering competitive pricing, GST billing, and shipping across India and overseas.

📋 Technical Specifications

Parameter	Value
Brand	BB40400B
Part Number / SKU	BB40400B
Category	Miniature Circuit Breaker (MCB)
Current Rating	40 A
Voltage Rating	415V AC
Poles	4 Poles
Breaking Capacity	10 kA
Tripping Curve	Curve B
Rated Voltage	230/400V AC
Rated Frequency	50/60 Hz
Magnetic Trip Range	3–5 × In (per IEC 60898-1)
Trip Mechanism	Thermal-magnetic (bimetal overload + electromagnetic short-circuit)
Mounting	35mm DIN rail (EN 60715)
Width	72 mm (4 × 18mm modules)
Electrical Endurance	≥ 20,000 operating cycles (per IEC 60898-1)
Pollution Degree	3 (per IEC 60664-1)
Standard	IS 8828 / IEC 60898-1 (residential) and IEC 60947-2 (industrial)
Certifications	BIS certified where applicable

⚡ Key Features

Protects circuits at 40 A with 10 kA short-circuit breaking capacity — rated for light industrial and commercial distribution boards.
Curve B tripping characteristic — optimised for cable and resistive loads (lighting, heating, socket circuits) — trips magnetically at 3–5× rated current.
4 Poles — protects a three-phase four-wire circuit with switched neutral; fits standard 35mm DIN rail in distribution boards.
Thermal-magnetic trip mechanism — bimetal element trips on sustained overload, instantaneous magnetic trip on short-circuit; two independent protection functions in one compact module.
Manufactured to IS 8828 / IEC 60898-1 (residential) and IEC 60947-2 (industrial) — complies with the applicable Indian BIS and IEC international standards for this product category.
BIS certified where applicable — meets Indian regulatory requirements for use in government, commercial, and industrial electrical installations.
Genuine authorised BB40400B product — sourced directly from the official distribution network with full manufacturer traceability and warranty.
GST invoice provided for India orders — valid for corporate procurement, government project orders, and public tender supply via myelectric.in.
Worldwide export available — UAE, Singapore, UK, USA, Sri Lanka & more. Contact +91 94814 00316 for bulk pricing and international shipping.

❓ Frequently Asked Questions

Q: What load can the BB40400B protect at its rated 40 A?

A: The BB40400B is rated to carry and protect circuits up to 40 A continuously. For motor loads, ensure the full-load current (FLC) of the motor does not exceed this rating. For resistive loads (heaters, lighting), the 40 A rating is used directly. Derate by 20% for ambient temperatures above 40°C.

Q: What does the 10 kA breaking capacity on the BB40400B mean in practice?

A: Breaking capacity (10 kA) is the maximum prospective short-circuit current the BB40400B can safely interrupt without damage. Before installing, verify that the prospective fault level at the installation point does not exceed 10 kA — this is checked using a fault level calculation or from the upstream transformer impedance data. Installing a breaker with insufficient breaking capacity is a serious safety violation.

Q: Why is Curve B specified for the BB40400B and what loads is it optimised for?

A: Curve B on the BB40400B trips magnetically at 3–5× rated current, making it ideal for resistive loads such as incandescent lighting, electric heaters, and PTC elements. Using the wrong curve can cause nuisance tripping (too sensitive) or inadequate protection (not sensitive enough). Always match the curve to the load’s inrush characteristics.

Q: Can the BB40400B be DIN rail mounted in any standard distribution board?

A: Yes. This BB40400B MCB uses the standard 35mm EN 60715 DIN rail and 17.5mm module width, making it compatible with all major brand distribution boards and enclosures. Terminal capacity accommodates both rigid and flexible conductors up to the rated cross-section.

Q: What happens when the BB40400B trips — how do I identify and reset it?

A: When the BB40400B trips on fault, the handle moves to a midway position (between ON and OFF), distinctly visible from a distance. To reset: (1) identify and rectify the fault, (2) push the handle fully to OFF, (3) then switch back to ON. Never force-reset without investigating the fault cause.