The Mersen A300518 (Catalogue No. PC71UD13C250TF) is a Protistor® Size 71 ultra-fast square body semiconductor fuse designed to protect sensitive power semiconductor devices including diodes, thyristors, IGBTs and similar components used in high-power conversion equipment. It is rated at 250A, 1250VAC (IEC) and 1300VAC (UL), with an aR operating class for semiconductor protection.
Designed for demanding industrial applications, the A300518 features a square body Size 71 construction with flush ends, metric threaded terminals and an integrated striker indicator. Silver-plated contact surfaces, high interrupting capacity and low energy let-through (I²t) provide reliable protection for expensive semiconductor equipment.
The Mersen A300518 is engineered specifically for protecting semiconductor devices operating in demanding power conversion systems. Its ultra-fast aR characteristic limits fault energy before damage can occur to expensive semiconductor components.
Typical applications include variable speed drives, UPS systems, renewable energy converters, industrial rectifiers, battery storage systems, DC drives, welding equipment and other power electronic installations requiring rapid fault interruption.
Typical Applications
Variable frequency drives (VFDs).
Industrial power converters.
UPS systems.
Solar inverters.
Battery energy storage systems.
Rectifiers.
Motor drives.
IGBT and thyristor protection.
Industrial automation equipment.
Technical Specifications
Item number
A300518
Catalogue No
PC71UD13C250TF
Description
Square Body High-Speed Fuse Protistor® Size 71 aR 1250VAC IEC 1300VAC UL 250A With Striker Flush ends metric threads
EAN/UPC Code
3605340329704
Rated voltage AC UL
1300 V
Rated voltage AC IEC
1250 V
Ampere Rating
250 A
AC or DC
AC
Speed/Characteristic
aR
Fuse Size
71
Mounting
Bolted
Clearing I2t At Rated Voltage
72 kA²s
Melting I2t
8.9 kA²s
AC Max I.R./Breaking Capacity
I1: 126 kA
Indication System
Yes
Indication System Type
Striker
Connection/Terminal Material
Silver-Plated Brass
Connection/Terminal Type
Flush ends
Product Width
51 mm
Product Length
74 mm
Product Height
56.5 mm
Sell Pack Quantity
3 EA
Sell Pack Weight
1.545 kg
Sell Pack Width
90 mm
Sell Pack Length
170 mm
Sell Pack Height
70 mm
Product group
Semiconductor Protection Fuses
Body/Insulating Material
Ceramic
Product Weight
0.515 kg
Power Dissipation at Rated Current Value
61 W
HS Code
85351000
Frequently Asked Questions
What is the Mersen A300518?
The Mersen A300518 (PC71UD13C250TF) is a Protistor® Size 71 ultra-fast aR semiconductor protection fuse rated at 250A for 1250VAC IEC and 1300VAC UL applications.
What does the aR fuse characteristic mean?
An aR fuse provides partial-range ultra-fast protection specifically for semiconductor devices such as IGBTs, thyristors and diodes, helping minimise fault energy before device damage occurs.
What equipment is the A300518 suitable for?
It is commonly used in variable speed drives, UPS systems, industrial converters, renewable energy systems, rectifiers and other power electronic equipment.
Does the fuse include an operation indicator?
Yes. The A300518 incorporates an integrated striker indicator for remote indication or microswitch operation.
Why choose a genuine Mersen Protistor® fuse?
Genuine Protistor® fuses are engineered specifically for semiconductor protection, providing high interrupting capacity, low I²t values and reliable performance in demanding industrial environments.
Trusted Semiconductor Protection
Mersen Protistor® high-speed fuses are trusted worldwide for protecting critical semiconductor devices in industrial drives, renewable energy installations, power conversion equipment and heavy-duty electrical systems.
Item number
A300518
Catalogue No
PC71UD13C250TF
Description
Square Body High-Speed Fuse Protistor® Size 71 aR 1250VAC IEC 1300VAC UL 250A With Striker Flush ends metric threads
EAN/UPC Code
3605340329704
Rated voltage AC UL
1300 V
Rated voltage AC IEC
1250 V
Ampere Rating
250 A
AC or DC
AC
Speed/Characteristic
aR
Fuse Size
71
Mounting
Bolted
Clearing I2t At Rated Voltage
72 kA²s
Melting I2t
8.9 kA²s
AC Max I.R./Breaking Capacity
I1: 126 kA
Indication System
Yes
Indication System Type
Striker
Connection/Terminal Material
Silver-Plated Brass
Connection/Terminal Type
Flush ends
Product Width
51 mm
Product Length
74 mm
Product Height
56.5 mm
Sell Pack Quantity
3 EA
Sell Pack Weight
1.545 kg
Sell Pack Width
90 mm
Sell Pack Length
170 mm
Sell Pack Height
70 mm
Product group
Semiconductor Protection Fuses
Body/Insulating Material
Ceramic
Product Weight
0.515 kg
Power Dissipation at Rated Current Value
61 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...