Fuse Selection Criteria
Peak Pulse Current (IPP)
For circuits that do not require additional series resistance, the surge current rating (I ) of
PP
the fuse should be greater than or equal to the surge currents associated with the lightning
immunity tests of the applicable regulatory requirement (IPK):
IPP O IPK
For circuits that use additional series resistance, the surge current rating (IPP) of the fuse
should be greater than or equal to the available surge currents associated with the lightning
immunity tests of the applicable regulatory requirement (IPK(available)):
IPP O IPK(available)
The maximum available surge current is calculated by dividing the peak surge voltage (VPK
by the total circuit resistance (RTOTAL):
)
I
PK(available) = VPK/RTOTAL
For longitudinal surges (Tip-Ground, Ring-Ground), RTOTAL is calculated for both Tip and
Ring:
R
SOURCE = VPK/IPK
RTOTAL = RTIP + RSOURCE
RTOTAL = RRING + RSOURCE
For metallic surges (Tip-Ring):
R
SOURCE = VPK/IPK
RTOTAL = RTIP + RRING + RSOURCE
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SIDACtor Data Book and Design Guide
TECCOR [ TECCOR ELECTRONICS ]
