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Mercury 5 x 20mm F1.25A Quick Blow Fuses - 250V

£149
The RRP is the manufacturer's recommended retail price of the item.
Limited Stock
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Description

The Mercury F1.25A is a 5 x 20mm glass cartridge quick blow fuse rated for 250V operation, designed to provide fast-acting circuit protection in low-current applications. The fuse uses a thin wire element inside a glass tube with nickel-plated brass end caps, breaking the circuit within milliseconds when current exceeds 1.25A.

Quick blow fuses are used in circuits where immediate disconnection is critical to protect sensitive components — audio equipment input stages, control circuits, battery-powered devices, and signal processing equipment. The 5 x 20mm format is a standard IEC cartridge size, fitting fuse holders in amplifiers, mixing desks, powered speakers, test equipment, and many consumer electronics. The glass body allows visual inspection of the fuse element without removal.

The 1.25A rating sits below the threshold of most general lighting or heating circuits but above milliamp-level signal circuits, making it appropriate for equipment drawing 150-300W at 230V or proportionally less at lower voltages. The nickel-plated brass caps resist corrosion and maintain consistent contact pressure in spring-clip fuse holders. Each fuse carries IEC approval for use in CE-compliant equipment.

Frequently Asked

What does 'quick blow' mean?

Quick blow (fast-acting) fuses break the circuit within milliseconds of the current exceeding the rating. They're used where immediate disconnection protects delicate components, unlike slow-blow fuses which tolerate brief surges.

What voltage can it handle?

The fuse is rated to 250V, covering both 230V UK mains applications and lower-voltage DC circuits common in audio and control equipment.

How do I know if the fuse has blown?

The glass body allows visual inspection. A blown fuse shows a broken wire element inside the tube, often with blackening on the glass if the fault was severe. An intact element appears as a continuous thin wire between the end caps.

Can I use this in a 13A plug fuse holder?

No. UK 13A plug fuses use a different cartridge size (25 x 6.3mm). This 5 x 20mm fuse fits panel-mount or PCB fuse holders commonly found inside equipment, not domestic plug tops.

Shipping & Returns

Delivery UK delivery is £14.99, and delivery is free on all orders of £99 or more, in the UK and internationally.

Returns If you change your mind, you have 14 days from delivery to tell us, and a further 14 days to send the goods back. Return postage for a change-of-mind return is paid by you. Change-of-mind returns are subject to an inspection and handling deduction. See our full returns policy.

To arrange a return, call us on 020 8149 5199 or use our contact page.

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    Description

    The Mercury F1.25A is a 5 x 20mm glass cartridge quick blow fuse rated for 250V operation, designed to provide fast-acting circuit protection in low-current applications. The fuse uses a thin wire element inside a glass tube with nickel-plated brass end caps, breaking the circuit within milliseconds when current exceeds 1.25A.

    Quick blow fuses are used in circuits where immediate disconnection is critical to protect sensitive components — audio equipment input stages, control circuits, battery-powered devices, and signal processing equipment. The 5 x 20mm format is a standard IEC cartridge size, fitting fuse holders in amplifiers, mixing desks, powered speakers, test equipment, and many consumer electronics. The glass body allows visual inspection of the fuse element without removal.

    The 1.25A rating sits below the threshold of most general lighting or heating circuits but above milliamp-level signal circuits, making it appropriate for equipment drawing 150-300W at 230V or proportionally less at lower voltages. The nickel-plated brass caps resist corrosion and maintain consistent contact pressure in spring-clip fuse holders. Each fuse carries IEC approval for use in CE-compliant equipment.

    Frequently Asked

    What does 'quick blow' mean?

    Quick blow (fast-acting) fuses break the circuit within milliseconds of the current exceeding the rating. They're used where immediate disconnection protects delicate components, unlike slow-blow fuses which tolerate brief surges.

    What voltage can it handle?

    The fuse is rated to 250V, covering both 230V UK mains applications and lower-voltage DC circuits common in audio and control equipment.

    How do I know if the fuse has blown?

    The glass body allows visual inspection. A blown fuse shows a broken wire element inside the tube, often with blackening on the glass if the fault was severe. An intact element appears as a continuous thin wire between the end caps.

    Can I use this in a 13A plug fuse holder?

    No. UK 13A plug fuses use a different cartridge size (25 x 6.3mm). This 5 x 20mm fuse fits panel-mount or PCB fuse holders commonly found inside equipment, not domestic plug tops.

    Shipping & Returns

    Delivery UK delivery is £14.99, and delivery is free on all orders of £99 or more, in the UK and internationally.

    Returns If you change your mind, you have 14 days from delivery to tell us, and a further 14 days to send the goods back. Return postage for a change-of-mind return is paid by you. Change-of-mind returns are subject to an inspection and handling deduction. See our full returns policy.

    To arrange a return, call us on 020 8149 5199 or use our contact page.