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Mercury 5 x 20mm T8A Slow Blow Fuses - 250V IEC Compliant

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

The Mercury T8A is a 5 x 20mm glass cartridge fuse rated at 8 amps and 250V, designed with time-delay (slow blow) characteristics to tolerate brief inrush currents without blowing. The fuse uses a thicker element than a fast-acting fuse, allowing it to withstand short-duration surges from motor start-up, transformer inrush, or capacitor charging while still breaking the circuit when a sustained overload or short circuit occurs.

Designed for electrical equipment, audio amplifiers, power supplies, motor control circuits, and any application where the load draws a temporary spike on start-up but operates within the 8A rating during normal running. The 5 x 20mm format is a standard cartridge size compatible with PCB-mount fuseholders, panel-mount fuseholders, and inline fuseholders used across consumer electronics, professional AV gear, and light industrial equipment.

The fuse carries IEC certification, confirming it meets international standards for breaking capacity and consistent performance under fault conditions. The glass body allows visual inspection of the element to confirm whether the fuse has blown. Each fuse is stamped with the rating (T8A) and voltage limit (250V) on the end cap for easy identification during installation or replacement.

Frequently Asked

What does 'slow blow' mean?

Slow blow (time-delay) fuses tolerate brief current surges above the rated amperage without blowing, giving equipment time to settle into its normal operating current. A fast-acting fuse would blow immediately on a motor start-up surge; a slow blow fuse allows the surge for a few seconds before breaking the circuit if the overcurrent persists.

What's the difference between T8A and F8A?

The 'T' prefix indicates a time-delay (slow blow) fuse. An 'F' prefix would indicate a fast-acting fuse that blows immediately on overcurrent. Both are 8A rated, but their response to surge current differs completely.

Is this fuse suitable for mains voltage use?

Yes. The 250V rating covers UK 230V mains circuits with headroom. The fuse is suitable for protecting mains-powered equipment, provided the steady-state current draw does not exceed 8A.

Can it be used in a 13A plug fuse carrier?

No. UK plug fuse carriers use 25 x 6.3mm cartridge fuses (BS 1362). The 5 x 20mm format is for equipment-level protection inside a device or in a separate inline fuseholder, not for 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 T8A is a 5 x 20mm glass cartridge fuse rated at 8 amps and 250V, designed with time-delay (slow blow) characteristics to tolerate brief inrush currents without blowing. The fuse uses a thicker element than a fast-acting fuse, allowing it to withstand short-duration surges from motor start-up, transformer inrush, or capacitor charging while still breaking the circuit when a sustained overload or short circuit occurs.

    Designed for electrical equipment, audio amplifiers, power supplies, motor control circuits, and any application where the load draws a temporary spike on start-up but operates within the 8A rating during normal running. The 5 x 20mm format is a standard cartridge size compatible with PCB-mount fuseholders, panel-mount fuseholders, and inline fuseholders used across consumer electronics, professional AV gear, and light industrial equipment.

    The fuse carries IEC certification, confirming it meets international standards for breaking capacity and consistent performance under fault conditions. The glass body allows visual inspection of the element to confirm whether the fuse has blown. Each fuse is stamped with the rating (T8A) and voltage limit (250V) on the end cap for easy identification during installation or replacement.

    Frequently Asked

    What does 'slow blow' mean?

    Slow blow (time-delay) fuses tolerate brief current surges above the rated amperage without blowing, giving equipment time to settle into its normal operating current. A fast-acting fuse would blow immediately on a motor start-up surge; a slow blow fuse allows the surge for a few seconds before breaking the circuit if the overcurrent persists.

    What's the difference between T8A and F8A?

    The 'T' prefix indicates a time-delay (slow blow) fuse. An 'F' prefix would indicate a fast-acting fuse that blows immediately on overcurrent. Both are 8A rated, but their response to surge current differs completely.

    Is this fuse suitable for mains voltage use?

    Yes. The 250V rating covers UK 230V mains circuits with headroom. The fuse is suitable for protecting mains-powered equipment, provided the steady-state current draw does not exceed 8A.

    Can it be used in a 13A plug fuse carrier?

    No. UK plug fuse carriers use 25 x 6.3mm cartridge fuses (BS 1362). The 5 x 20mm format is for equipment-level protection inside a device or in a separate inline fuseholder, not for 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.