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Mercury 5 x 20mm F3.15A Quick Blow Fuses - 250V Glass

£149
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Description

The Mercury F3.15A is a 5x20mm quick blow fuse housed in a clear glass tube with nickel-plated brass end caps. Rated at 250V, the fuse uses a thin wire element that melts rapidly when current exceeds 3.15A, interrupting the circuit before sensitive components can be damaged. Quick blow fuses respond faster than time-delay or slow-blow types, making them suited to circuits where transient spikes are rare and immediate protection is needed.

These fuses fit standard 5x20mm clips and holders in consumer electronics, mains-powered audio equipment, small power supplies, bench multimeters, and low-current appliances where over-current protection is required by design or regulation. The 3.15A rating sits between the more common 2A and 5A sizes, providing closer protection margins for circuits drawing 2-2.8A under normal load.

The clear glass tube allows visual inspection of the wire element — if the fuse has blown, the break in the wire is visible without needing a continuity tester. The nickel-plated end caps resist corrosion in humid environments and maintain good contact with spring-loaded clips. Each fuse is manufactured to IEC 60127 standards, ensuring consistent breaking capacity and dimensional accuracy across production batches.

Frequently Asked

What does 'quick blow' mean?

Quick blow (or fast-acting) fuses respond immediately to over-current conditions without intentional time delay. The thin wire element melts within milliseconds once the rated current is exceeded, providing rapid protection for sensitive circuits that cannot tolerate brief over-current spikes.

Can this replace a slow-blow fuse of the same rating?

No. Slow-blow (time-delay) fuses are designed to tolerate brief inrush currents during motor start-up or capacitor charging. Using a quick blow fuse in place of a slow-blow will result in nuisance blowing during normal operation. Always replace with the same fuse type specified by the equipment manufacturer.

What voltage is it rated for?

This fuse is rated at 250V, meaning it can safely interrupt a circuit operating at up to 250V AC or DC. Using it in higher-voltage circuits risks arcing or failure to interrupt the fault.

How do I know if the fuse has blown?

The clear glass tube allows you to visually inspect the wire element inside. If blown, you'll see a visible break in the wire or a dark scorch mark on the glass. If the element appears intact, test with a continuity meter to confirm.

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. Refunds are made in line with our returns policy, which has the full details.

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

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    Description

    The Mercury F3.15A is a 5x20mm quick blow fuse housed in a clear glass tube with nickel-plated brass end caps. Rated at 250V, the fuse uses a thin wire element that melts rapidly when current exceeds 3.15A, interrupting the circuit before sensitive components can be damaged. Quick blow fuses respond faster than time-delay or slow-blow types, making them suited to circuits where transient spikes are rare and immediate protection is needed.

    These fuses fit standard 5x20mm clips and holders in consumer electronics, mains-powered audio equipment, small power supplies, bench multimeters, and low-current appliances where over-current protection is required by design or regulation. The 3.15A rating sits between the more common 2A and 5A sizes, providing closer protection margins for circuits drawing 2-2.8A under normal load.

    The clear glass tube allows visual inspection of the wire element — if the fuse has blown, the break in the wire is visible without needing a continuity tester. The nickel-plated end caps resist corrosion in humid environments and maintain good contact with spring-loaded clips. Each fuse is manufactured to IEC 60127 standards, ensuring consistent breaking capacity and dimensional accuracy across production batches.

    Frequently Asked

    What does 'quick blow' mean?

    Quick blow (or fast-acting) fuses respond immediately to over-current conditions without intentional time delay. The thin wire element melts within milliseconds once the rated current is exceeded, providing rapid protection for sensitive circuits that cannot tolerate brief over-current spikes.

    Can this replace a slow-blow fuse of the same rating?

    No. Slow-blow (time-delay) fuses are designed to tolerate brief inrush currents during motor start-up or capacitor charging. Using a quick blow fuse in place of a slow-blow will result in nuisance blowing during normal operation. Always replace with the same fuse type specified by the equipment manufacturer.

    What voltage is it rated for?

    This fuse is rated at 250V, meaning it can safely interrupt a circuit operating at up to 250V AC or DC. Using it in higher-voltage circuits risks arcing or failure to interrupt the fault.

    How do I know if the fuse has blown?

    The clear glass tube allows you to visually inspect the wire element inside. If blown, you'll see a visible break in the wire or a dark scorch mark on the glass. If the element appears intact, test with a continuity meter to confirm.

    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. Refunds are made in line with our returns policy, which has the full details.

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