Wöhner 31278 AMBUS Panel single-pole DIN rail-mounted semiconductor fuse holder for 14 × 51 mm cylindrical fuse links, rated at 50 A and 690 V AC under IEC specifications.
£22.41
The Wöhner 31278 is a robust single-pole DIN rail-mounted fuse holder for 14 × 51 mm cylindrical fuse links. Designed for semiconductor fuse applications, it provides a secure and compact mounting solution for protecting power electronic equipment in industrial control panels, machinery and electrical distribution systems.
Rated at 50 A and 690 V AC under IEC conditions, the Wöhner 31278 supports high-speed aR, gR and gRL semiconductor fuse links as well as compatible gG and aM fuse links within the manufacturer’s specified power-dissipation limits. Its large conductor clamping range and integrated label holder help simplify panel assembly, wiring and circuit identification.
The holder is suitable for standard mounting-rail installation and features touch-safe IP20 protection. With approvals including IEC, UL, CSA and CCC, plus AC and DC ratings under UL, the Wöhner 31278 is an adaptable choice for industrial applications requiring dependable cylindrical fuse protection.
Semiconductor fuse links are designed to interrupt damaging fault currents rapidly, helping protect sensitive components such as rectifiers, inverters, thyristors and variable-speed drives. The Wöhner 31278 provides the secure mechanical and electrical interface needed to install compatible 14 × 51 mm high-speed fuse links within an industrial panel.
Its wide conductor range supports flexible panel wiring, while the integrated label holder improves circuit identification during installation and maintenance. The compact 27 mm width also helps conserve valuable DIN rail space.
For aR, gR and gRL fuse links with power dissipation up to 6.5 W, Wöhner specifies that conductors of at least 25 mm² must be connected. The holder must only be used with copper conductors, as it is not suitable for aluminium cables.
| Current | 50 A |
|---|---|
| Manufacturer | Wöhner |
| Product range | AMBUS Panel |
| Model | 31278 |
| Full part number | 31278000 |
| Product type | Semiconductor cylindrical fuse holder |
| Fuse-link size | 14 × 51 mm |
| Fuse-link standard | IEC / HD 60269-2 |
| Configuration | 1P |
| Rated current IEC | 50 A |
| Rated voltage IEC | 690 V AC |
| Rated insulation voltage | 800 V AC / DC |
| Rated impulse withstand voltage | 6 kV |
| Rated current UL | 50 A |
| Rated voltage UL | 600 V AC / DC |
| Rated frequency UL | 50 / 60 Hz |
| UL short-circuit current rating | 100 kA |
| Conditional short-circuit rating | 80 kA at 690 V with 25 A fuse |
| Approved fuse operating class | gG |
| Suitable semiconductor fuse classes | aR, gR and gRL |
| Permitted fuse-link power dissipation | 6.5 W |
| Typical device power dissipation at 80% load | 0.6 W |
| Device power dissipation at full load | 0.9 W |
| Dimensions (W × H × D) | 27 × 90 × 69 mm |
| Approximate weight | 97 g |
| Mounting | DIN rail |
| Degree of protection | IP20 |
| Front degree of protection | IP20 |
| Terminal type | Cage-clamp connection |
| Conductor cross-section | 1.5 to 35 mm² |
| UL conductor range | AWG 14 to AWG 2 |
| Wire stripping length | 14 mm |
| Terminal tightening torque | 2.5 to 3.0 Nm |
| Minimum operating temperature | -40°C |
| Suitable for aluminium conductors | No |
| Halogen free | Yes |
| Pack size | 6 |
| EAN | 4021267312787 |
| ECLASS 14.0 | 27142190 |
| ETIM classification | EC002705 |
| Standards | IEC 60947-1:2020, IEC 60947-3:2020 and UL 4248-1 |
| Approvals | IEC CB, UL, CSA and CCC |
| Type number | AES14x51 |
The Wöhner 31278 accepts 14 × 51 mm cylindrical fuse links manufactured in accordance with IEC or HD 60269-2.
The fuse holder has a rated current of 50 A under both IEC and UL specifications.
It is rated at 690 V AC under IEC specifications and 600 V AC or DC under UL specifications.
Yes. It is designed for semiconductor fuse applications and supports compatible aR, gR and gRL fuse links, subject to the manufacturer’s power-dissipation and conductor-size requirements.
The cage-clamp terminals accept copper conductors from 1.5 to 35 mm². Aluminium conductors must not be used.
Yes. The holder is designed for standard DIN rail installation in electrical control panels and distribution assemblies.
The fuse holder measures approximately 27 × 90 × 69 mm.
Wöhner AMBUS Panel fuse holders are trusted by panel builders, OEM manufacturers and industrial engineers for secure installation, dependable circuit protection and compliance with recognised international electrical standards.
● Service Agreements
Credit Accounts
Our service agreements are built to support long term procurement relationships. By working closely with engineering teams and procurement departments, we help streamline purchasing processes while ensuring consistent access to critical components and sourcing support when it matters most.
● frequently asked questions
At Led Controls Ltd we help engineers source the right automation and control gear with confidence. below are quick answers to what we are asked most often.
We supply all leading manfacturers in our industry. we offer next day delivery on most poplour products.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
Your content goes here. Edit or remove this text inline or in the module Content settings. You can also style every aspect of this content in the module Design settings and even apply custom CSS to this text in the module Advanced settings.
● latest blog
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...