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Mercury T3.15A 5 x 20mm Slow 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 T3.15A is a 5 x 20mm glass slow blow fuse rated at 250V, designed to protect sensitive electronics from overcurrent conditions while tolerating the brief inrush currents that occur when equipment powers up. The glass tube construction allows visual inspection of the fuse wire, so you can confirm whether the fuse has blown without needing a multimeter.

Slow blow fuses use a thicker fuse wire or a spring-loaded mechanism that delays the break action, allowing short-duration current surges to pass without triggering the fuse. This makes them suitable for audio amplifiers, power supplies, motor controllers and other devices where the startup current can spike to several times the running load for a fraction of a second. The 3.15A rating handles continuous loads up to approximately 750W at 240V.

The 5 x 20mm cartridge format is a standard size for panel-mount fuseholders and PCB-mount clips in consumer electronics, PA equipment and lighting controllers. The metal end caps provide reliable contact with spring-clip fuseholders and can withstand repeated insertion and removal cycles during maintenance. These fuses meet IEC 60127 international standards for safety and performance.

Frequently Asked

What's the difference between slow blow and fast blow fuses?

Slow blow (time-delayed) fuses tolerate brief current surges without breaking, so they suit equipment with high startup currents like amplifiers and motors. Fast blow fuses break immediately when the rated current is exceeded, offering faster protection for sensitive circuits with no inrush tolerance.

What equipment uses 5 x 20mm fuses?

This format is common in PA amplifiers, mixing desks, lighting controllers, power supplies, battery chargers and consumer audio equipment. Check your equipment's user manual or the markings on the existing fuse to confirm the correct size and rating.

Can I use a higher-rated fuse if this one keeps blowing?

No. The fuse rating is chosen to protect the downstream circuit from damage. If a T3.15A fuse blows repeatedly, there is a fault in the equipment or the load exceeds the design limit. Using a higher-rated fuse removes the protective function and risks damaging the equipment or creating a fire hazard.

How do I know if the fuse has blown?

The glass tube allows you to see the internal fuse wire. If the wire is broken or the glass has darkened from arcing, the fuse has blown and needs replacing.

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 T3.15A is a 5 x 20mm glass slow blow fuse rated at 250V, designed to protect sensitive electronics from overcurrent conditions while tolerating the brief inrush currents that occur when equipment powers up. The glass tube construction allows visual inspection of the fuse wire, so you can confirm whether the fuse has blown without needing a multimeter.

    Slow blow fuses use a thicker fuse wire or a spring-loaded mechanism that delays the break action, allowing short-duration current surges to pass without triggering the fuse. This makes them suitable for audio amplifiers, power supplies, motor controllers and other devices where the startup current can spike to several times the running load for a fraction of a second. The 3.15A rating handles continuous loads up to approximately 750W at 240V.

    The 5 x 20mm cartridge format is a standard size for panel-mount fuseholders and PCB-mount clips in consumer electronics, PA equipment and lighting controllers. The metal end caps provide reliable contact with spring-clip fuseholders and can withstand repeated insertion and removal cycles during maintenance. These fuses meet IEC 60127 international standards for safety and performance.

    Frequently Asked

    What's the difference between slow blow and fast blow fuses?

    Slow blow (time-delayed) fuses tolerate brief current surges without breaking, so they suit equipment with high startup currents like amplifiers and motors. Fast blow fuses break immediately when the rated current is exceeded, offering faster protection for sensitive circuits with no inrush tolerance.

    What equipment uses 5 x 20mm fuses?

    This format is common in PA amplifiers, mixing desks, lighting controllers, power supplies, battery chargers and consumer audio equipment. Check your equipment's user manual or the markings on the existing fuse to confirm the correct size and rating.

    Can I use a higher-rated fuse if this one keeps blowing?

    No. The fuse rating is chosen to protect the downstream circuit from damage. If a T3.15A fuse blows repeatedly, there is a fault in the equipment or the load exceeds the design limit. Using a higher-rated fuse removes the protective function and risks damaging the equipment or creating a fire hazard.

    How do I know if the fuse has blown?

    The glass tube allows you to see the internal fuse wire. If the wire is broken or the glass has darkened from arcing, the fuse has blown and needs replacing.

    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.