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4. Determine time-to-trip.
Time-to-trip is the amount of time it takes for a device to switch to a
high-resistance state once a fault current has been applied across the
device.
Identifying the RUE device’s time-to-trip is important in order to provide
the desired protection capabilities. If the device you choose trips
too fast, undesired or nuisance tripping will occur. If the device trips
too slowly, the components being protected may be damaged before
the device switches to a high-resistance state.
The chart below shows the typical time-to-trip at 20°C for each
PolySwitch RUE device. For example, the chart indicates that the typi-
cal time-to-trip for RUE110 at 8 A is 1 second.
On the chart below, find the typical time-to-trip for the RUE device you
selected. If the RUE device’s time-to-trip is too fast or too slow for the
circuit, go back to Step 2 and choose an alternate device.
Typical time-to-trip at 20°C
A = RUE090
B = RUE110
C = RUE135
D = RUE160
E = RUE185
F = RUE250
G = RUE300
H = RUE400
I = RUE500
J = RUE600
K = RUE700
L = RUE800
M = RUE900
144 RUE Devices
Raychem Circuit Protection Devices
RUE
Radial Leaded
1000
1
10
100
Fault current (A)
M
L
K
J
I
H
G
F
E
D
C
B
A
100
10
1
0.1
0.01
0.001
4
RUE(7)
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