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What are KF7 Fuse Holders used for?

KF7 fuse holders can be applied on the line side of KTA7 or KTC7 motor circuit controllers and matching CA7 contactors to increase the short-circuit protection of a group installation per NEC 430-53C, or a single branch circuit per NEC 430-52.C. KF7 can also be connected on the line side of a CA7 contactor and/or starter as you would a standard fuse holder, such as the Wohner Ambus product line. The short-circuit rating of the assembly is increased to 100 KAIC with Type CC fuses as shown in section A of the E-Catalog. KF7 fuse holders can also be used with the same close couple connectors used for KTA7 and KF7 will accept a KT7 integral mount auxiliary contact.

We have some Canadian customers using KF7 where the KF7 helps fill the gap for Type E at 600/Y347 Volts and we asked them share a couple of pictures of their control panels. Some of their reasons for using KF7 are as follows:

• KF7 are 45mm wide, same as the contactor, so they are perfectly in line with the contactor below and do not require extra space
• In opposition with open fuse holder, KF7 offers a touch safe design
• The most important one is that you can padlock the fuse holder in the open position.

It is good to make note of their last reason, the lockable feature of the KF7 fuse holders. This is often required for safety during maintenance. Other fuse holders require add-on accessories for this feature that might not be readily available.

This control panel is dedicated to the operation of miscellaneous equipment in a poultry farm. (Click to enlarge)

This control panel takes care of the operations of an oil press and auxiliary equipment in a soybean processing plant. (Click to enlarge)