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Mercury 5 x 20mm F100mA Quick Blow Glass Fuse - 250V

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

The Mercury F100mA is a 5 x 20mm glass cartridge fuse rated at 100 milliamps and 250V, designed for fast-acting circuit protection in low-current applications. The quick blow construction disconnects the circuit within milliseconds of the current exceeding 100mA, protecting sensitive components in audio equipment, control circuits, and instrumentation before damage can occur.

Quick blow fuses differ from slow blow or time-delay types by offering no tolerance for current surges — the internal wire melts immediately when the rated current is exceeded. This makes the F100mA suitable for circuits where components cannot withstand even brief overcurrent conditions, such as pre-amplifier stages, microphone phantom power lines, MIDI interfaces, and low-voltage control boards. The 5 x 20mm cartridge format fits standard panel-mount and PCB-mount fuseholders across AVSL, Adastra and Citronic audio products.

The glass tube construction allows visual inspection of the internal fuse element to confirm whether the fuse has blown without needing a continuity tester. The nickel-plated brass end caps provide reliable contact and resist corrosion in installations where the equipment may be stored or used in variable humidity. Each fuse is IEC-compliant and manufactured to standard tolerances for drop-in replacement in existing equipment.

Frequently Asked

What is the difference between quick blow and slow blow fuses?

Quick blow fuses disconnect the circuit immediately when the rated current is exceeded, offering no tolerance for brief surges. Slow blow (time-delay) fuses allow temporary current spikes without blowing, making them suitable for motors and transformers that draw higher current on startup. The F100mA quick blow is designed for circuits that cannot tolerate any overcurrent condition.

What equipment typically uses a 100mA fuse?

The F100mA rating is common in pre-amplifiers, microphone phantom power circuits, small signal processors, MIDI interfaces, LED control circuits, and other low-power audio or control equipment where the operating current is well below 100mA and higher currents indicate a fault.

Can I use this fuse in mains voltage equipment?

The 250V rating covers UK mains voltage (230V), but the 100mA current rating is far too low for mains appliances. This fuse is intended for low-current secondary circuits within equipment, not primary mains protection.

How do I know if the fuse has blown?

The glass tube allows you to see the internal fuse wire. If the wire is intact and continuous, the fuse is good. If the wire is broken or you see a dark deposit on the inside of the glass, 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 F100mA is a 5 x 20mm glass cartridge fuse rated at 100 milliamps and 250V, designed for fast-acting circuit protection in low-current applications. The quick blow construction disconnects the circuit within milliseconds of the current exceeding 100mA, protecting sensitive components in audio equipment, control circuits, and instrumentation before damage can occur.

    Quick blow fuses differ from slow blow or time-delay types by offering no tolerance for current surges — the internal wire melts immediately when the rated current is exceeded. This makes the F100mA suitable for circuits where components cannot withstand even brief overcurrent conditions, such as pre-amplifier stages, microphone phantom power lines, MIDI interfaces, and low-voltage control boards. The 5 x 20mm cartridge format fits standard panel-mount and PCB-mount fuseholders across AVSL, Adastra and Citronic audio products.

    The glass tube construction allows visual inspection of the internal fuse element to confirm whether the fuse has blown without needing a continuity tester. The nickel-plated brass end caps provide reliable contact and resist corrosion in installations where the equipment may be stored or used in variable humidity. Each fuse is IEC-compliant and manufactured to standard tolerances for drop-in replacement in existing equipment.

    Frequently Asked

    What is the difference between quick blow and slow blow fuses?

    Quick blow fuses disconnect the circuit immediately when the rated current is exceeded, offering no tolerance for brief surges. Slow blow (time-delay) fuses allow temporary current spikes without blowing, making them suitable for motors and transformers that draw higher current on startup. The F100mA quick blow is designed for circuits that cannot tolerate any overcurrent condition.

    What equipment typically uses a 100mA fuse?

    The F100mA rating is common in pre-amplifiers, microphone phantom power circuits, small signal processors, MIDI interfaces, LED control circuits, and other low-power audio or control equipment where the operating current is well below 100mA and higher currents indicate a fault.

    Can I use this fuse in mains voltage equipment?

    The 250V rating covers UK mains voltage (230V), but the 100mA current rating is far too low for mains appliances. This fuse is intended for low-current secondary circuits within equipment, not primary mains protection.

    How do I know if the fuse has blown?

    The glass tube allows you to see the internal fuse wire. If the wire is intact and continuous, the fuse is good. If the wire is broken or you see a dark deposit on the inside of the glass, 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.