The Protistor® PC70UD13C125PA high-speed fuse offers superior protection for sensitive power semiconductor devices in demanding industrial applications. Rated at 125A with voltage operation up to 1300VAC (IEC) and 1250VAC (UL), it ensures rapid fault interruption and enhanced system reliability.
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Why Choose the Mersen K301125 High-Speed Semiconductor Fuse?
The Mersen K301125 is an industrial high-speed semiconductor protection fuse designed to safeguard sensitive power electronic components against damaging short-circuit currents. Manufactured by Mersen, it is suitable for professionally engineered electrical systems requiring rapid fault interruption and effective limitation of energy let-through.
High-speed fuses are commonly used to protect IGBTs, thyristors, diodes, rectifiers, inverters and power conversion equipment. Their fast operating characteristics help reduce thermal and electrical stress on valuable semiconductor devices, supporting improved equipment reliability and reduced unplanned downtime.
The K301125 is intended for installation within a correctly coordinated industrial protection system. Its exact current rating, voltage rating, utilisation category, breaking capacity, terminal arrangement and physical dimensions should be confirmed from the product label or official Mersen technical documentation before selection or installation.
Key Advantages
Designed for high-speed semiconductor protection.
Rapid fault interruption helps minimise damaging energy let-through.
Suitable for industrial power conversion and motor-control equipment.
Helps protect valuable semiconductor components against short circuits.
Industrial-grade construction for demanding electrical environments.
Suitable for OEM, maintenance and replacement applications.
Key Features
Mersen high-speed industrial fuse.
Manufacturer reference K301125.
Designed for semiconductor device protection.
Fast-acting response to high short-circuit currents.
Suitable for coordinated industrial protection systems.
Designed for use with a compatible fuse holder or mounting assembly.
Suitable for power electronic and automation equipment.
Manufactured for professional electrical installations.
Primary function: Protection of power semiconductor devices
Rated current: Confirm from the product label or official Mersen datasheet
Rated voltage: Confirm from the product label or official Mersen datasheet
Operating characteristic: Confirm from official Mersen documentation
Breaking capacity: Confirm from the product label or official Mersen datasheet
Pre-arcing I²t: Confirm from official Mersen documentation
Clearing I²t: Confirm from official Mersen documentation
Terminal type: Confirm from the product configuration
Indication system: Confirm from the product configuration
Mounting type: Compatible industrial fuse mounting system
Dimensions: Confirm from official Mersen documentation
Installation environment: Industrial electrical and power electronic systems
Reliable Protection for Industrial Power Electronics
Semiconductor fuses are designed to operate considerably faster than conventional general-purpose fuses. By interrupting excessive current before damaging thermal energy reaches sensitive electronic components, they help protect power modules and reduce the risk of extensive equipment failure.
The Mersen K301125 should be selected according to the circuit voltage, normal operating current, prospective short-circuit current and the protection requirements of the connected semiconductor devices. Any replacement fuse must provide compatible electrical characteristics, mounting arrangements and physical dimensions.
Typical Applications
Variable frequency drives and motor controllers.
Industrial inverters and power converters.
IGBT, thyristor and diode protection.
Uninterruptible power supply systems.
Renewable energy conversion equipment.
Industrial automation and control panels.
High-power rectifier and semiconductor circuits.
Technical Specifications
Item number
K301125
Catalogue No
PC70UD13C125PA
Description
Square Body High-Speed Fuse Protistor® Size 70 aR 1250VAC IEC 1300VAC UL 125A Striker Plain Blades
EAN/UPC Code
3605340337204
Rated voltage AC UL
1300 V
Rated voltage AC IEC
1250 V
Ampere Rating
125 A
AC or DC
AC
Speed/Characteristic
aR
Fuse Size
72
Mounting
Clip
Clearing I2t At Rated Voltage
10500 A²s
Melting I2t
1310 A²s
AC Max I.R./Breaking Capacity
I1: 126 kA
Indication System
Yes
Indication System Type
Striker
Connection/Terminal Material
Silver-Plated Copper
Connection/Terminal Type
Plain Blades
Product Width
39.8 mm
Product Length
123.4 mm
Product Height
49.5 mm
Sell Pack Quantity
3 EA
Sell Pack Weight
1.092 kg
Sell Pack Width
140 mm
Sell Pack Length
143 mm
Sell Pack Height
65 mm
Product group
Semiconductor Protection Fuses
Body/Insulating Material
Ceramic
Product Weight
0.364 kg
Power Dissipation at Rated Current Value
38 W
HS Code
85351000
Frequently Asked Questions
What is the Mersen K301125 used for?
The K301125 is designed to provide high-speed protection for sensitive semiconductor devices used in industrial power electronic equipment.
What components can the K301125 protect?
It may be used in compatible circuits to protect components such as IGBTs, thyristors, diodes, rectifiers and power converter modules.
How can the electrical ratings be confirmed?
The rated current, voltage, operating characteristic and breaking capacity should be confirmed from the fuse label or official Mersen technical documentation before installation.
Can the K301125 replace another fuse model?
It should only be used as a replacement when its electrical ratings, operating characteristics, terminals and physical dimensions are fully compatible with the original fuse.
Where is the Mersen K301125 typically installed?
It may be installed in compatible industrial drives, power converters, UPS equipment, renewable energy systems and semiconductor protection assemblies.
Trusted Industrial Semiconductor Protection
Mersen high-speed fuses are used by engineers, panel builders, equipment manufacturers and maintenance professionals to help protect critical power electronic systems against damaging short-circuit currents.
Item number
K301125
Catalogue No
PC70UD13C125PA
Description
Square Body High-Speed Fuse Protistor® Size 70 aR 1250VAC IEC 1300VAC UL 125A Striker Plain Blades
EAN/UPC Code
3605340337204
Rated voltage AC UL
1300 V
Rated voltage AC IEC
1250 V
Ampere Rating
125 A
AC or DC
AC
Speed/Characteristic
aR
Fuse Size
72
Mounting
Clip
Clearing I2t At Rated Voltage
10500 A²s
Melting I2t
1310 A²s
AC Max I.R./Breaking Capacity
I1: 126 kA
Indication System
Yes
Indication System Type
Striker
Connection/Terminal Material
Silver-Plated Copper
Connection/Terminal Type
Plain Blades
Product Width
39.8 mm
Product Length
123.4 mm
Product Height
49.5 mm
Sell Pack Quantity
3 EA
Sell Pack Weight
1.092 kg
Sell Pack Width
140 mm
Sell Pack Length
143 mm
Sell Pack Height
65 mm
Product group
Semiconductor Protection Fuses
Body/Insulating Material
Ceramic
Product Weight
0.364 kg
Power Dissipation at Rated Current Value
38 W
HS Code
85351000
No documents available for this product.
Delivery
We offer fast UK delivery on all stocked items. Orders placed before 3pm Monday to Friday are eligible for next-day delivery.
Standard delivery: 2–3 working days
Next-day delivery: available on in-stock items when ordered before 3pm
Express options available — contact us for details
Returns
If you need to return an item, please contact our sales team within 30 days of receipt. Items must be returned unused in their original packaging.
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Customers supported
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LED Controls is a specialist distributor of factory automation and industrial controls, supplying OEMs, machine builders, panel builders and end users throughout the UK and worldwide. As a trusted UK distributor for many of the world’s leading automation manufacturers, we provide industrial control products, technical expertise and bespoke automation solutions backed by outstanding customer service.
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...
2025 has been a big year for LED Controls, and our blog has expanded accordingly. We've covered a wide range of topics across industrial control and factory automation this year. From core technology explainers and new product releases to panel building best practice...