Highfields Amateur Radio Club
Constructors Corner.

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.

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

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

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.

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.

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:

• The fuse must carry 110% of its ampere rating and must stabilise at a temperature that does not exceed a 75°C rise at 100%.
  The fuse must open at 135% of rated current within one hour.
  It also must open at 200% of rated current within:
  • 2 minutes for 0-30 ampere ratings
  • 4 minutes for 35-60 ampere ratings.
  
  
  
• The interrupting rating of a UL Listed fuse is 10,000 amperes AC minimum at 125 volts.
  Fuses rated at 250 volts may be listed as interrupting 10,000 amperes at 125 volts and, at least, the minimum values shown below at 250 volts.

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

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.