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Figure 12.3 - SF6 circuit breakers in a high voltage switchyard

3. Epoxy

While epoxy has good thermal characteristics and excellent
adhesion, if not used properly during the manufacturing process, it
can ruin components in a high voltage assembly. Stresses during
the potting process can damage components.
Thermal stresses during equipment operation can also damage
components due to unequal thermal expansion and contraction. In
addition, the epoxy curing process can be highly exothermic and
parts can be damaged by heat generated during curing.
Epoxy modules are unrepairable, so if there is a failure, the
assembly must be discarded.
The other implication is that failure analyses are severely
limited, making it difficult to learn from any problems that crop
up.

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