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chemicals is only during cleaning and typically not when the equipment is in use.
Though switches with splash proof boots do not provide a com-
plete seal, they do offer adequate protection against a variety of
contaminating factors. Boots come in a variety of materials, each best
suited to specific applications. Thus, it is also important to choose the
right material for every environment. Six of the most common boot
• Silicone rubber, which provides very good hot, cold, ozone, aging
and ultra-violet light resistance. It also offers very good flexibility, re-
silience and tensile strength over a wide temperature range. However,
it is less tear resistant than some other materials, so proper care must
be used during installation.
• Natural rubber, which is a great choice for panel seals and gaskets.
• Polyvinyl chloride (PVC), which is typically only used for dust
proof covers as other materials provide superior resistance against all
other types of contaminants.
• Nitrile butadiene rubber (NBR), which offers an excellent balance
between protecting against oil and cold temperatures, good elasticity and prolonged performance. However, it provides inferior ozone
• Ethylene propylene rubber (EPR), which while offering good hot,
cold, dust, ozone and water proofing, it provides mediocre oil resistance.
Switch manufacturers can often retrofit most switch types, including pushbutton, rocker, rotary and toggle switches, with splash proof
boots. The only exceptions are typically heavy-duty power rotary
and slide switches. While splash proof boots are an excellent choice
for many designs, there are some common pitfalls that often come up
during the boot installation process. These include improper panel
material or panel thickness, the wrong boot for a specific switch,
improper torque sequence or assembly process and insufficient thread
Q: When is the redundancy of an IP-rated switch with a splash
proof boot recommended?
A: If an application requiring an IP-rated switch impacts the safety
of either the equipment or human life, designing in such redundancy
is important to ensure the highest level of protection against contamination and disastrous switch failure can be essential.
For example, industrial control environments typically only require
IP-rated switches. However, when safety is a factor in such environments, an IP-rated device with a splash proof boot is recommended.
Consider the possibility that in such an environment, the switch
housing could become compromised; thus, breaking the housing’s
seal. The protective boot would provide a second but necessary barrier of defense against contaminants.
Engineers should answer several questions when selecting a switch
for industrial control environments. These include:
• What types of processes are being used in the facility?
• What is being made in the facility?
• Are there any contaminants or environmental circumstances that
could potentially affect switch performance?