Installation design data for the KHK Series fuse
1. Recommended mounting hole pitch
・660KHK (600KHK) series

・400KHK (350KHK) series

Reference value
HoleLand

Referencevalue
Land

Hole

Unit: mm

Unit: mm

2. Clearance and creepage distance
When the fuse cuts off, a large voltage is applied between both terminals. The recommended
values of the distance between the land and from other devices, is shown in the table below.
Distance between both terminal land
Coated mount board

Un-coated mount board

Distance between the fuse
and the other device

400KHK(350KHK)More than 3mm

More than 5mm

More than 4mm

660KHK(600KHK)

More than 5mm

More than 8mm

More than 6mm

Product series

For the application of 400KHK (350KHK), if the distance between the terminals needs to belarger, because of the possibility of insulation decline due to contamination on the mounting
board, or if the distance between the terminals is shorter due to your company provisions,please use 660KHK(660KHK) instead.
3. Temperature rise
Fuse temperature changes according to the width of the pattern and the conduction current.

Thetemperature rise characteristics, as shown below, follow a pattern that becomes 1A/mm (copperfoil thickness:35μm) at the time of conducting a current that is 50% of the fuse’s rated current.
Please refer to the data when designing a pattern.
 Conditions
Board size: 150mm X 100mm
Board material: FR-4
Copper foil thickness: 35μm

Unit: mm

Data No. 05-10-26 (1/6)

 400KHK (350KHK) Temperature rise characteristics

Center of the cylinder

Terminal

Temperature rise value (℃)

400KHK10

Center of the cylinder

Terminal

Conduction current (A) rms

400KHK15400KHK20

Center of the cylinder

Terminal

Temperature rise value (℃)

Conduction current (A) rms

Center of the cylinder

Terminal

Conduction current (A) rms

Conduction current (A) rms

400KHK25

400KHK30

Center of the cylinder

Terminal

Conduction current (A) rms

Temperature rise value (℃)

Temperature rise value (℃)

Temperature rise value (℃)

Temperature rise value (℃)

400KHK05

Center of the cylinder

Terminal

Conduction current (A) rms

Temperature rise value (℃)

400KHK35

Center of the cylinder

Terminal

Conduction current (A) rms

Data No. 05-10-26 (2/6)



660KHK (600KHK) Temperature rise characteristics
660KHK10Terminal

Temperature rise value (℃)

Center of the cylinder

Center of the cylinder

Terminal

Conduction current (A) rms

660KHK15

660KHK20

Center of the cylinder

Terminal

Temperature rise value (℃)

Conduction current (A) rms

Center of the cylinder

Terminal

Conduction current (A) rms

Conduction current (A) rms

660KHK25

660KHK30

Center of the cylinder

Terminal

Temperature rise value (℃)

Temperature rise value (℃)

Temperature rise value (℃)

Temperature rise value (℃)

660KHK05

Center of the cylinder

Terminal

Conduction current (A) rms

Conduction current (A) rms

Temperature rise value (℃)

660KHK35

Center of the cylinder
Terminal

Conduction current (A) rms

Data No. 05-10-26 (3/6)

4. Temperature rise value of the board
Due to the heating of the fuse and/or from the pattern, the board temperature around the fuseincreases.

Please consider this when designing the placement of devices.

The curves below

show the relationship of the surrounding temperature distribution on the board at each amperage.
Please refer to the data when designing.
 400KHK (350KHK)
Copper foil line-Board
Relationship between distance and temperature riseStandard value
Temperature risevalue of the terminal

Temperature rise ratio (％)

Temperature rise ratio (％)

Terminal-Copper foil
Relationship between distance and temperature riseStandard value
Temperature rise value
on a copper foil line

Distance (mm)Distance (mm)

 660KHK (600KHK)Standard value
Temperature risevalue of the terminal

Distance (mm)Copper foil line-Board
Relationship between distance and temperature riseTemperature rise ratio (％)

Temperature rise ratio (％)

Terminal-Copper foil
Relationship between distance and temperature riseStandard value
Temperature rise value
on a copper foil line

Distance (mm)※ “ON COPPER FOIL LINE” means a centerline that connects the copper foilat the both ends. This includes the fuse on the same line.
※ If the conduction current value is lower than the fuse rated value (lowerthan 25%), temperature rise ratio may decrease by about 20%.

Data No. 05-10-26 (4/6)

 Calculation of the temperature rise value at a random pointFor example） When conducting 25A current into 400KHK25
Unit: mmFuse

Copper foil

Copper foil line
Terminal location※ Terminal location is about 5mm apart from the center of the fuse.
From the 400KHK25 Temperature Rise Characteristics graph, the temperature rise value of thefuse and fuse terminal are read as follows;・Temperature rise value at the center of the cylinder: About 100℃
・Temperature rise value at the terminal: About 90℃a) Plot point A:
From the graph, Terminal-Copper foil Relationship between distance and temperature rise, thetemperature rise ratio at the distance of 25mm is about 70%.
90℃ (the terminal temperature rise) X 70% (temperature rise ratio) = 63℃
The temperature rise value at plot point A is around 63℃.
b) Plot point B:
From the graph, Terminal-Copper foil Relationship between distance and temperature rise, thetemperature rise ratio at the distance of 55mm is about 55%.
90℃ (the terminal temperature rise) X 55% (temperature rise ratio) = 50℃
The temperature rise value at plot point B is around 50℃.
c) Plot point ①:
From the graph, Copper foil line-board Relationship between distance and temperature rise, thetemperature rise ratio at the distance of 20mm is about 35%.
100℃ (the temperature rise at the center of the cylinder) X 35% (temperature rise ratio) = 35℃
The temperature rise value at plot point ① is around 35℃.
d) Plot point ②:
From the graph, Copper foil line-board Relationship between distance and temperature rise, thetemperature rise ratio at the distance of 20mm is about 35%.
63℃ (the temperature rise value at plot point A) X 35% (temperature rise ratio) = 22℃
The temperature rise value at plot point ② is around 22℃.

Data No. 05-10-26 (5/6)

e) Plot point ③:
From the graph, Copper foil line-board Relationship between distance and temperature rise, thetemperature rise ratio at the distance of 40mm is about 22%.
50℃ (the temperature rise value at plot point B) X 22% (temperature rise ratio) = 11℃
The temperature rise value at plot point ③ is around 11℃.
※ To calculate the temperature rise value at a random point, it is necessary at first to measure thetemperature rise value on the copper foil line that is vertical to the random point.

Data No. 05-10-26 (5/6)