Taken directly from a competitor’s website, is this description of their watertight limit switch “…have internal parts that are protected against splashing or hose-directed water seepage within the limits of the NEMA specified tests for type 4 watertight enclosures. These switches are not sleet or ice-proof.”
That’s a lot of words to say, “not really waterproof”.
For engineers looking for a small form factor, truly waterproof and can’t-kill-it-with-a-hammer limit switch we offer, well…our whole product line. To break it down lets take a look at the major types of switches and switch configurations we manufacture.
Ball and Plunger Limit Switches
Our J4 series limit switches come in both a ball and a plunger variation. These have seen use in military vehicles, construction vehicles, emergency and work trucks, even submarines. These switches can be mechanically activated by a transmission sliding into neutral, or a door or hood closing, or a valve opening up and reaching the limit of its travel, or any one of a hundred other applications where size and durability were the primary concerns.
Made of all stainless steel with a patented double seal mechanism, these switches are usually the final resort of engineers who don’t want to mess around with safety limit switches who fail in the field. That’s because configurations of our limit switches have been qualified to over one million cycles.
Shown here is one of our cab down detect applications for a military transport. These applications can use our J4 plunger switch typically though many make use of our E1 series switches discussed below.
E1 Series Limit Switches
When you take one of our Santoprene or Neoprene (extended temperature range) sealed momentary or maintained contact pendant switches and combine them with CPI’s custom actuators and bracket mounting options, the result is a broad line of waterproof limit switches that can be readily configured for your specific applications, usually with an off the shelf purchase from one of our distributors. Many combinations of travel parameters, electrical configurations, roller lever or panel mounting configurations as well as our standard high-endurance capabilities are offered as standard products.
It’s Easier to say “Heavy Duty” with CPI Limit Switches.
Did we mention that our limit switches actually operate underwater? And at -40F or 220F? Here’s how we say that in our product description.
“CPI limit switches are waterproof and weatherproof.”
Easy right?
Original content posted on https://www.cpi-nj.com/blog/a-heavy-duty-limit-switch-with-a-simple-explanation/
Pictured here is our E1008 surface bracket used with any of our B series Momentary Waterproof Switches or K Series 
In this application our B9112 switch uses a simulated roller actuator to detect mechanical closure for anything from a truck door to a dump body. The mounting bracket is our standard stainless steel right angle mounting bracket. The switch internals are held inside the bracket, sealed in Santoprene including lead connections which can be ordered in any length. The switch itself can be any of our momentary or maintained 
Our curved metal pipe mount bracket is easily secured to a wide variety of common pipe diameters. Shown here is our 
In this configuration, any two of our low profile momentary or maintained pendent switches can be used to create redundant, or complementary sensing of mechanical actuation. All lead connections are sealed within the neoprene coating.
One great example of an emergency vehicle application is the use of our E1005-B7151 waterproof limit switch as a hidden ambulance door open switch. Used by several ambulance manufacturers like Braun and PL Custom, these hidden waterproof switches allow operators into the vehicles when keys are not available to open the door. (You know, like when someone locks them in the ambulance…) Our switch Is mounted by manufacturers in a “hidden” area that is known only to the ambulance operators and allows them quick access in an emergency.
Versalift Chose our 
The E1092 is a great example of a 
One of the key features of Hagie sprayers is their long hydraulically controlled booms which can spread out on either side of the cab, yielding a wingspan of up to 132 feet! Critical to operation of these booms is that they travel to a locked position so that liquids are sprayed evenly and accurately. To provide closed loop feedback on the mechanical locking mechanism, a limit switch is typically used which is activated when the boom reaches its locked position. The problem however, is that these switches must be deployed in an area completely exposed to outdoor conditions on the boom including sprayed compounds like Urea Ammonium Nitrate (URN) which has excellent properties as a fertilizer when mixed with water. Unfortunately, it is also highly corrosive to steel over time and Hagie had difficulty finding a limit switch for this application that did not ultimately degrade, and require expensive field repairs.
There are a number of safety systems present in Forklifts and Telehandlers for which CPI waterproof switch products often get selected. Since these specialized vehicles often operate outdoors in less than ideal conditions on construction sites, a tough and durable switch is essential to both equipment uptime, and job safety.
For this application our J4001 ball switch is often used owing to its highly robust all stainless steel design, and its qualification for extreme electromechanical endurance. At the heart of the J4 is a patented ball carrier design which prevents contaminates such as mud, dirt, ice, sand, dust, etc. from jamming the ball. Furthermore the switches are completely submersible and are unaffected by water, salt spray, humidity, dirt, dust, sand, icing, oil, shock and vibration.
site, you’ve for sure heard that loud annoying beeping sound whenever a lift moves backwards. That doesn’t happen without the engagement of a switch like our E1078 
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