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Constructors Corner.
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Fuses: The Markings.
By Brian, MW0GKX.

The Fuses, What and Why page gives the history, purpose and some other basic information about fuses, while the De-coding Glass Fuses page covers the equipment markings and coloured spot or band marked fuses.

On this page I will go into the other markings that you may come across either stampped into the end caps or printed on the fuse body and, in some cases, the detail behind the marking.

BS mark British Standards Institute (also called Kite Mark)

Granted by British Standards Institute here in the UK. Guarantees that a fuse or fuse holder has been manufactured in full compliance to the appropriate section of the IEC 60127 (BS EN 60127) standard.

SEMKO mark SEMKO

Granted by Intertek-ETL Semko in Sweden. Guarantees that a fuse or fuse holder has been manufactured in full compliance to the appropriate section of the IEC 60127 standard.

VDE mark VDE

Granted by VDE Institute in Germany. Guarantees that a fuse or fuse holder has been manufactured in full compliance to the appropriate section of the IEC 60127 standard.

CSA mark Canadian Standards Association

Granted by the Canadian Standards Association. Guarantees that a fuse or fuse holder has been manufactured in full compliance with the CSA C22.2 No. 248.14 or CSA C22.2 No. 39 standard respectively. It is equivalent to UL Listing for the U.S.A.

UL mark Underwriters Laboratories Listed

Granted by the Underwriters Laboratories in the US. Guarantees that a fuse has been manufactured in full compliance with the UL/CSA/ANCE (Mexico) 248-14 standard: Fuses for Supplementary Overcurrent Protection (600 Volts, Maximum). Some of the requirements are as follows:

Fuse Amperage
(Amp)
Fuse
Interrupt Ratinging
(Amp)
Fuse
Rated Voltage
(Volt)
0 to 1 35 250VAC
1.1 to 3.5 100 250VAC
3.6 to 10 200 250VAC
10.1 to 15 750 250VAC
15.1 to 30 1500 250VAC

ULR mark Underwriters Laboratories Recognised

Tested under the Underwriters Laboratories Component Recognition Program. This is for components for which there is no UL standard, or where only certain sections of a particular UL standard are referenced. A fuse or fuse holder may be submitted testing according to criteria defined by the manufacturer. If basic safety requirements are met during testing and the component performs as predicted it can be UL Recognised.

Usually parts bearing these marks are incorporated into equipment and designed to provide protection for the components in that equipment.

Fuses and fuse holders built to the IEC 60127 standard (with BSI, SEMKO or VDE approval) are technically qualified for UL Recognition.

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