AU HR MCB 125A SP 240V AC 15kA D Curve | L&T – AU15S11253D

Name: L&T AU15S11253D 125A SP MCB, D Curve, 15kA
Brand: Lauritz Knudsen (L&T)
SKU: AU15S11253D
Price: 2433.60 INR
Availability: InStock

SKU: AU15S11253D

Original price was: ₹5,070.00.Current price is: ₹2,433.60. Excl. GST

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📋 Technical Specifications

Parameter	Value
Brand	AU15S11253D
Part Number / SKU	AU15S11253D
Category	Miniature Circuit Breaker (MCB)
Current Rating	125 A
Voltage Rating	240V AC
Poles	1 Pole
Breaking Capacity	15 kA
Tripping Curve	Curve D
Standard	IS 8828 / IEC 60898-1 (residential) and IEC 60947-2 (industrial)
Certifications	BIS certified where applicable

⚡ Key Features

Protects circuits at 125 A with 15 kA short-circuit breaking capacity — rated for industrial sub-distribution boards with high prospective fault currents.
Curve D tripping characteristic — optimised for high-inrush loads (transformers, solenoids, welding machines) — trips magnetically at 10–20× rated current.
1 Pole — protects a single-phase final circuit; 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 AU15S11253D 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 AU15S11253D protect at its rated 125 A?

A: The AU15S11253D is rated to carry and protect circuits up to 125 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 125 A rating is used directly. Derate by 20% for ambient temperatures above 40°C.

Q: What does the 15 kA breaking capacity on the AU15S11253D mean in practice?

A: Breaking capacity (15 kA) is the maximum prospective short-circuit current the AU15S11253D can safely interrupt without damage. Before installing, verify that the prospective fault level at the installation point does not exceed 15 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 D specified for the AU15S11253D and what loads is it optimised for?

A: Curve D on the AU15S11253D trips magnetically at 10–20× rated current, making it ideal for highly inductive loads with large inrush — transformers, large motors, welding machines. 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 AU15S11253D be DIN rail mounted in any standard distribution board?

A: Yes. This AU15S11253D 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 AU15S11253D trips — how do I identify and reset it?

A: When the AU15S11253D 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.