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Mercury 5 x 20mm F8A Quick Blow Fuses - Pack of 5

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

The Mercury F8A is a 5 x 20mm quick blow fuse rated at 8A and 250V, designed to break the circuit immediately when current exceeds the rated threshold. The fast-acting response protects sensitive electronics and low-power appliances from damage caused by overcurrent faults or short circuits.

These fuses are used in domestic and commercial equipment including audio amplifiers, test equipment, power supplies, small motors, control panels and lighting controllers where rapid fault protection is required. The standard 5 x 20mm glass tube format fits most fuse holders designed to IEC 60127 specifications, making them compatible with a wide range of UK and European equipment.

The glass tube construction allows visual inspection of the internal wire element, so a blown fuse can be identified without a continuity tester. Each fuse carries the F8A rating marking on the metal end caps. Supplied in packs of 5.

Frequently Asked

What does 'quick blow' mean?

Quick blow (also called fast-acting) fuses are designed to break the circuit almost instantly when current exceeds the rated value. This contrasts with time-delay fuses, which tolerate brief surges. Quick blow fuses are used where the connected equipment cannot safely handle even short-duration overcurrent.

What's the difference between F8A and T8A fuses?

F8A is a fast-acting (quick blow) fuse that breaks immediately on overcurrent. T8A is a time-delay fuse that can tolerate brief surges before breaking. Use F8A for sensitive electronics; use T8A for inductive loads like motors that draw higher current on startup.

Are these suitable for mains plugs?

No. Standard UK mains plugs require 13A cartridge fuses to BS 1362 (the larger plug-top format). These 5 x 20mm glass fuses are for equipment-level protection inside appliances, power supplies and control panels.

How can I tell if a fuse has blown?

The glass tube allows you to see the internal wire element. If the wire is intact, the fuse is still functional. If the wire has broken or the glass is blackened, the fuse has blown and must be replaced.

Shipping & Returns

Free worldwide delivery

Free worldwide delivery on all orders over £99. International orders for third-party brand products may be subject to an additional courier surcharge based on volumetric weight, particularly on larger lighting fixtures — if a surcharge applies, our team will email you with the amount before dispatch and you can proceed or cancel for a full refund. See full delivery terms.

Returns

30-day returns window from delivery. As all our products are electrical or lighting goods, returned items must be inspected and recertified by a qualified electrician before resale — the cost of this inspection (25–40% of the item value) is deducted from your refund. Customers pay return shipping. Made-to-order, special-order and clearance items cannot be returned. See full returns policy.

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    Description

    The Mercury F8A is a 5 x 20mm quick blow fuse rated at 8A and 250V, designed to break the circuit immediately when current exceeds the rated threshold. The fast-acting response protects sensitive electronics and low-power appliances from damage caused by overcurrent faults or short circuits.

    These fuses are used in domestic and commercial equipment including audio amplifiers, test equipment, power supplies, small motors, control panels and lighting controllers where rapid fault protection is required. The standard 5 x 20mm glass tube format fits most fuse holders designed to IEC 60127 specifications, making them compatible with a wide range of UK and European equipment.

    The glass tube construction allows visual inspection of the internal wire element, so a blown fuse can be identified without a continuity tester. Each fuse carries the F8A rating marking on the metal end caps. Supplied in packs of 5.

    Frequently Asked

    What does 'quick blow' mean?

    Quick blow (also called fast-acting) fuses are designed to break the circuit almost instantly when current exceeds the rated value. This contrasts with time-delay fuses, which tolerate brief surges. Quick blow fuses are used where the connected equipment cannot safely handle even short-duration overcurrent.

    What's the difference between F8A and T8A fuses?

    F8A is a fast-acting (quick blow) fuse that breaks immediately on overcurrent. T8A is a time-delay fuse that can tolerate brief surges before breaking. Use F8A for sensitive electronics; use T8A for inductive loads like motors that draw higher current on startup.

    Are these suitable for mains plugs?

    No. Standard UK mains plugs require 13A cartridge fuses to BS 1362 (the larger plug-top format). These 5 x 20mm glass fuses are for equipment-level protection inside appliances, power supplies and control panels.

    How can I tell if a fuse has blown?

    The glass tube allows you to see the internal wire element. If the wire is intact, the fuse is still functional. If the wire has broken or the glass is blackened, the fuse has blown and must be replaced.

    Shipping & Returns

    Free worldwide delivery

    Free worldwide delivery on all orders over £99. International orders for third-party brand products may be subject to an additional courier surcharge based on volumetric weight, particularly on larger lighting fixtures — if a surcharge applies, our team will email you with the amount before dispatch and you can proceed or cancel for a full refund. See full delivery terms.

    Returns

    30-day returns window from delivery. As all our products are electrical or lighting goods, returned items must be inspected and recertified by a qualified electrician before resale — the cost of this inspection (25–40% of the item value) is deducted from your refund. Customers pay return shipping. Made-to-order, special-order and clearance items cannot be returned. See full returns policy.