G4A01084C Datasheet, PDF (16/22 Pages) List of Unclassifed Manufacturers – MICROTEMP Thermal Cutoffs INTRODUCTION

Splices & Terminals
Insecure splices and terminations may produce high resistance junctions which can cause self
heating (I²R) as power is dissipated across these junctions during product operation.
Heat from these hot spots can flow down the thermal cutoff leads and increase the temperature
of the thermal cutoff (see figure 13). Nuisance openings of the thermal cutoffs or degradation of
the epoxy seal can occur as a result of the heat generated by high resistance junctions. The splice
or termination junction may initially measure low resistance, but can change to a much higher
resistance after several temperature cycles. It is generally better to splice MICROTEMP^® thermal
cutoff leads to stranded lead wires rather than solid wires as the stranded wire may be crimped
tighter and maintain better electrical contact during temperature cycling.
NUT
SPLICE
HEAT FLOW
HEAT FLOW
LOCK
WASHER
SPLICE
SPLICE
TERMINATION
Figure 13
BOLT
The temperature capabilities of the splice and/or termination should be considered. For example,
solder back-up should be considered for splices of terminations in applications cycled at temperatures
exceeding 150°C.
Bending Leads
When configuring leads, special care must be exercised in supporting the leads at each end near
the body of the thermal cutoff so that the case will not be distorted or the epoxy will not be
cracked or broken. At least 0.125” (3mm) should be maintained between the epoxy seal and any
lead bends (see figure 14).
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