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Mercury 5 x 20mm T1.25A Slow Blow Fuse - 250V IEC Approved

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

The Mercury T1.25A is a 5 x 20mm slow blow fuse rated to 1.25A at 250V, built with a time-delay element that tolerates short inrush current peaks without rupturing. The glass tube houses a thin nickel-plated copper wire mounted on nickel-plated brass end caps, visible through the transparent casing for visual confirmation of blown status.

Designed for low-current electronics that draw transient surge loads during startup or switching, the slow blow characteristic allows temporary overcurrent events (motor startup, capacitor charging, transformer energisation) to pass without breaking the circuit, while still protecting against sustained overload or short circuit faults. Common applications include audio equipment, LED drivers, control panels, and small power supplies where nuisance tripping from standard fast-blow fuses would be a problem.

The 5 x 20mm format fits standard panel-mount fuse holders, PCB-mount clips, and in-line cable holders across consumer electronics, industrial control gear, and test equipment. The IEC approval confirms the fuse meets international safety standards for breaking capacity and time-delay characteristics. Each fuse is marked with the current rating and time-delay designation (T1.25A) on the end cap for identification when installed.

Frequently Asked

What does 'slow blow' mean?

Slow blow (also called time-delay or T-rated) fuses tolerate brief overcurrent surges without blowing, then rupture under sustained overload. This prevents nuisance tripping from startup currents in motors, transformers and capacitive loads, while still protecting against genuine faults.

What voltage rating does it carry?

The fuse is rated to 250V. It can be used on lower voltages (12V, 24V, 48V, 120V circuits) but not on voltages exceeding 250V.

How do I know if the fuse has blown?

The glass tube is transparent. When the fuse blows, the internal wire element ruptures and you will see a visible break in the wire, often with scorch marks on the inside of the glass. If the wire appears intact and continuous, the fuse is still functional.

Can it replace a fast-blow fuse of the same rating?

Not directly. Slow blow and fast blow fuses have different time-current characteristics. Using a slow blow fuse where a fast blow is specified may leave the circuit under-protected during fault conditions. Always replace fuses with the same type (slow blow or fast blow) and rating specified by the equipment manufacturer.

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 T1.25A is a 5 x 20mm slow blow fuse rated to 1.25A at 250V, built with a time-delay element that tolerates short inrush current peaks without rupturing. The glass tube houses a thin nickel-plated copper wire mounted on nickel-plated brass end caps, visible through the transparent casing for visual confirmation of blown status.

    Designed for low-current electronics that draw transient surge loads during startup or switching, the slow blow characteristic allows temporary overcurrent events (motor startup, capacitor charging, transformer energisation) to pass without breaking the circuit, while still protecting against sustained overload or short circuit faults. Common applications include audio equipment, LED drivers, control panels, and small power supplies where nuisance tripping from standard fast-blow fuses would be a problem.

    The 5 x 20mm format fits standard panel-mount fuse holders, PCB-mount clips, and in-line cable holders across consumer electronics, industrial control gear, and test equipment. The IEC approval confirms the fuse meets international safety standards for breaking capacity and time-delay characteristics. Each fuse is marked with the current rating and time-delay designation (T1.25A) on the end cap for identification when installed.

    Frequently Asked

    What does 'slow blow' mean?

    Slow blow (also called time-delay or T-rated) fuses tolerate brief overcurrent surges without blowing, then rupture under sustained overload. This prevents nuisance tripping from startup currents in motors, transformers and capacitive loads, while still protecting against genuine faults.

    What voltage rating does it carry?

    The fuse is rated to 250V. It can be used on lower voltages (12V, 24V, 48V, 120V circuits) but not on voltages exceeding 250V.

    How do I know if the fuse has blown?

    The glass tube is transparent. When the fuse blows, the internal wire element ruptures and you will see a visible break in the wire, often with scorch marks on the inside of the glass. If the wire appears intact and continuous, the fuse is still functional.

    Can it replace a fast-blow fuse of the same rating?

    Not directly. Slow blow and fast blow fuses have different time-current characteristics. Using a slow blow fuse where a fast blow is specified may leave the circuit under-protected during fault conditions. Always replace fuses with the same type (slow blow or fast blow) and rating specified by the equipment manufacturer.

    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.