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Mercury 5 x 20mm T12A 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 T12A is a 12-amp slow blow fuse in a 5 x 20mm glass cartridge format, rated for 250V AC circuits. The slow blow (time-delay) characteristic allows the fuse to tolerate short-term current surges from motor startup, transformer inrush or capacitive loads without breaking the circuit, while still opening rapidly on sustained overloads above the rated 12A.

Designed for use in audio amplifiers, PA systems, powered speakers, mains-powered lighting equipment and general electronic devices where inrush current can briefly exceed the steady-state operating current. The 5 x 20mm cartridge size is a standard European format found in IEC-compliant mains input modules, inline fuse holders and equipment back panels. Each fuse uses nickel-plated brass end caps and a sand-filled glass tube for arc suppression when the element breaks.

The T12A rating means the fuse will hold 12A continuously at ambient temperature and will open within a defined time window on overcurrent events. The delay characteristic is calibrated to tolerate typical startup transients that last 10-50 milliseconds without nuisance tripping. IEC compliant construction ensures compatibility with standard fuse clips and holders across equipment from different manufacturers.

Frequently Asked

What does "slow blow" mean?

Slow blow (or time-delay) fuses tolerate brief current surges above the rated amperage without breaking, but still open on sustained overloads. This prevents nuisance tripping from motor startup, transformer inrush or capacitor charging transients.

Is this suitable for 240V UK mains?

Yes. The 250V rating covers UK mains voltage (230V nominal) with headroom for voltage variation. The fuse is designed for use in IEC mains input modules and equipment back panels.

How many fuses are in the pack?

Pack quantity is not specified in the product data. Contact us to confirm pack size before ordering if you need a specific quantity for a project or installation.

Can I replace a fast-blow fuse with this slow blow type?

Only if the equipment manufacturer specifies a slow blow fuse is acceptable. Replacing a fast-blow with a slow-blow reduces overcurrent protection speed and may allow fault conditions to persist longer than the circuit design intended.

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 T12A is a 12-amp slow blow fuse in a 5 x 20mm glass cartridge format, rated for 250V AC circuits. The slow blow (time-delay) characteristic allows the fuse to tolerate short-term current surges from motor startup, transformer inrush or capacitive loads without breaking the circuit, while still opening rapidly on sustained overloads above the rated 12A.

    Designed for use in audio amplifiers, PA systems, powered speakers, mains-powered lighting equipment and general electronic devices where inrush current can briefly exceed the steady-state operating current. The 5 x 20mm cartridge size is a standard European format found in IEC-compliant mains input modules, inline fuse holders and equipment back panels. Each fuse uses nickel-plated brass end caps and a sand-filled glass tube for arc suppression when the element breaks.

    The T12A rating means the fuse will hold 12A continuously at ambient temperature and will open within a defined time window on overcurrent events. The delay characteristic is calibrated to tolerate typical startup transients that last 10-50 milliseconds without nuisance tripping. IEC compliant construction ensures compatibility with standard fuse clips and holders across equipment from different manufacturers.

    Frequently Asked

    What does "slow blow" mean?

    Slow blow (or time-delay) fuses tolerate brief current surges above the rated amperage without breaking, but still open on sustained overloads. This prevents nuisance tripping from motor startup, transformer inrush or capacitor charging transients.

    Is this suitable for 240V UK mains?

    Yes. The 250V rating covers UK mains voltage (230V nominal) with headroom for voltage variation. The fuse is designed for use in IEC mains input modules and equipment back panels.

    How many fuses are in the pack?

    Pack quantity is not specified in the product data. Contact us to confirm pack size before ordering if you need a specific quantity for a project or installation.

    Can I replace a fast-blow fuse with this slow blow type?

    Only if the equipment manufacturer specifies a slow blow fuse is acceptable. Replacing a fast-blow with a slow-blow reduces overcurrent protection speed and may allow fault conditions to persist longer than the circuit design intended.

    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.