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Mercury 5 x 20mm T315mA Slow Blow Fuse - 250V IEC

£149
The RRP is the manufacturer's recommended retail price of the item.
Limited Stock
We are an Independent UK Company
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Description

The Mercury 5 x 20mm T315mA is a slow blow fuse rated at 315mA and 250V, designed to protect sensitive electronic circuits from sustained overcurrent while tolerating brief inrush surges. The glass tube body measures 5mm in diameter by 20mm in length, with nickel-plated brass end caps that fit standard PCB-mount and panel-mount fuse holders.

Slow blow fuses differ from fast-acting fuses by incorporating a time-delay element that allows temporary current spikes to pass without blowing the fuse. This makes them suitable for audio equipment, power supplies, motor controllers and other circuits where switch-on inrush current briefly exceeds the steady-state operating current. The T315mA rating means the fuse will carry 315mA continuously and tolerate short surges above that threshold without interrupting the circuit.

The fuse carries IEC certification, confirming it meets international safety and performance standards for overcurrent protection devices. The glass body allows visual inspection of the internal element to confirm whether the fuse has blown. Each fuse weighs approximately 0.3g and can be replaced without soldering in clip-style or drawer-style fuse holders.

Frequently Asked

What does 'slow blow' mean?

Slow blow fuses include a time-delay element that allows brief current surges to pass without blowing. This prevents nuisance blowing during switch-on or other temporary high-current events, while still protecting the circuit from sustained overcurrent.

What's the difference between T315mA and F315mA?

The 'T' prefix indicates a time-delay (slow blow) characteristic. An 'F' prefix would indicate a fast-acting fuse with no delay. For circuits with inrush current, the T-rated version is usually the correct choice.

What voltage is this rated for?

The fuse is rated at 250V. This is the maximum voltage at which the fuse can safely interrupt an overcurrent fault. Using it in circuits below 250V is acceptable; using it above 250V is not.

How do I know if the fuse has blown?

The glass body allows you to see the internal element. A blown fuse will show a broken or discoloured wire inside the tube. If the element appears intact and continuous, the fuse is likely still functional.

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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Free delivery on orders over £99, in the UK and worldwide. Easy returns within 14 days, subject to our returns policy. Full manufacturer warranty included.

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    Description

    The Mercury 5 x 20mm T315mA is a slow blow fuse rated at 315mA and 250V, designed to protect sensitive electronic circuits from sustained overcurrent while tolerating brief inrush surges. The glass tube body measures 5mm in diameter by 20mm in length, with nickel-plated brass end caps that fit standard PCB-mount and panel-mount fuse holders.

    Slow blow fuses differ from fast-acting fuses by incorporating a time-delay element that allows temporary current spikes to pass without blowing the fuse. This makes them suitable for audio equipment, power supplies, motor controllers and other circuits where switch-on inrush current briefly exceeds the steady-state operating current. The T315mA rating means the fuse will carry 315mA continuously and tolerate short surges above that threshold without interrupting the circuit.

    The fuse carries IEC certification, confirming it meets international safety and performance standards for overcurrent protection devices. The glass body allows visual inspection of the internal element to confirm whether the fuse has blown. Each fuse weighs approximately 0.3g and can be replaced without soldering in clip-style or drawer-style fuse holders.

    Frequently Asked

    What does 'slow blow' mean?

    Slow blow fuses include a time-delay element that allows brief current surges to pass without blowing. This prevents nuisance blowing during switch-on or other temporary high-current events, while still protecting the circuit from sustained overcurrent.

    What's the difference between T315mA and F315mA?

    The 'T' prefix indicates a time-delay (slow blow) characteristic. An 'F' prefix would indicate a fast-acting fuse with no delay. For circuits with inrush current, the T-rated version is usually the correct choice.

    What voltage is this rated for?

    The fuse is rated at 250V. This is the maximum voltage at which the fuse can safely interrupt an overcurrent fault. Using it in circuits below 250V is acceptable; using it above 250V is not.

    How do I know if the fuse has blown?

    The glass body allows you to see the internal element. A blown fuse will show a broken or discoloured wire inside the tube. If the element appears intact and continuous, the fuse is likely still functional.

    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.