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Mercury 5 x 20mm T250mA Slow Blow Fuses - Glass Cartridge

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

The Mercury T250mA is a 5 x 20mm glass cartridge slow blow fuse rated at 250mA (0.25A) on 250V circuits. The time-delay design allows brief inrush currents during equipment startup or motor spin-up before blowing, while still protecting against sustained overcurrent conditions that would damage sensitive low-power electronics.

Designed for use in audio equipment, small transformers, power supply boards, LED drivers, control panels and other low-current circuits where a standard fast-blow fuse would nuisance-trip during normal operation. The 5 x 20mm dimension is the IEC standard for small panel-mount and PCB fuseholders, making these fuses compatible with most European and UK electrical equipment using this form factor.

The glass tube body allows visual inspection of the internal fuse element without removal, so a blown fuse can be identified at a glance. The nickel-plated brass end caps provide reliable contact with the fuseholder terminals and resist corrosion in damp or dusty environments. Each fuse is IEC compliant and suitable for incorporation into CE-marked equipment.

Frequently Asked

What does 'slow blow' mean?

A slow blow (time-delay) fuse allows brief overcurrent surges during startup without blowing, but will interrupt the circuit if the overcurrent condition persists for more than a few milliseconds. This prevents nuisance blowing in circuits with inductive loads or capacitor charging.

What equipment uses 5 x 20mm fuses?

This fuse size is common in audio amplifiers, mixing desks, powered speakers, LED power supplies, small transformers, control boards and electronic test equipment. Check your equipment manual or the existing fuse marking to confirm size and rating before replacement.

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

Only if the equipment manufacturer specifies a slow blow (time-delay or 'T' rated) fuse in the original design. Using a slow blow fuse where a fast blow is specified can allow prolonged overcurrent conditions that damage components before the fuse blows.

What does the 'T' designation mean?

The 'T' prefix in T250mA indicates a time-delay (slow blow) characteristic, as opposed to 'F' for fast-acting or no prefix for medium-speed fuses. This is part of the IEC fuse rating standard.

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 T250mA is a 5 x 20mm glass cartridge slow blow fuse rated at 250mA (0.25A) on 250V circuits. The time-delay design allows brief inrush currents during equipment startup or motor spin-up before blowing, while still protecting against sustained overcurrent conditions that would damage sensitive low-power electronics.

    Designed for use in audio equipment, small transformers, power supply boards, LED drivers, control panels and other low-current circuits where a standard fast-blow fuse would nuisance-trip during normal operation. The 5 x 20mm dimension is the IEC standard for small panel-mount and PCB fuseholders, making these fuses compatible with most European and UK electrical equipment using this form factor.

    The glass tube body allows visual inspection of the internal fuse element without removal, so a blown fuse can be identified at a glance. The nickel-plated brass end caps provide reliable contact with the fuseholder terminals and resist corrosion in damp or dusty environments. Each fuse is IEC compliant and suitable for incorporation into CE-marked equipment.

    Frequently Asked

    What does 'slow blow' mean?

    A slow blow (time-delay) fuse allows brief overcurrent surges during startup without blowing, but will interrupt the circuit if the overcurrent condition persists for more than a few milliseconds. This prevents nuisance blowing in circuits with inductive loads or capacitor charging.

    What equipment uses 5 x 20mm fuses?

    This fuse size is common in audio amplifiers, mixing desks, powered speakers, LED power supplies, small transformers, control boards and electronic test equipment. Check your equipment manual or the existing fuse marking to confirm size and rating before replacement.

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

    Only if the equipment manufacturer specifies a slow blow (time-delay or 'T' rated) fuse in the original design. Using a slow blow fuse where a fast blow is specified can allow prolonged overcurrent conditions that damage components before the fuse blows.

    What does the 'T' designation mean?

    The 'T' prefix in T250mA indicates a time-delay (slow blow) characteristic, as opposed to 'F' for fast-acting or no prefix for medium-speed fuses. This is part of the IEC fuse rating standard.

    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.