Ingression protection is a commonly requested solenoid feature. As dirt, dust, moisture, and other foreign objects accumulate in a solenoid, the performance and life cycle are dramatically reduced. There are several methods to combat ingression, but before choosing the correct solution it is important to understand the degrees of protection available. International Protection (or IP) ratings are an industry standard used to measure the effective limits of ingress protection for electronic devices. An IP rating is commonly expressed as IPXY, where X represents the number given to the level of protection from solids and Y represents the number given to the level of protection from liquids and vapors.


For solids protections, there are 7 levels.

  • 0-No Protection
  • 1-Protection from objects over 50mm
  • 2-Protection from objects over 12.5mm
  • 3-Protection from objects over 2.5mm
  • 4-Protection from objects over 1mm
  • 5- Protection from the ingression of solids and is protected against dust, but not completely sealed.
  • 6- Protection from solids and completely sealed against dust.


For liquids, there are a greater range of levels relevant to solenoids.

  • 0-No protection
  • 1-Protection from drips from above
  • 2-Protection from drips from a slight angle (15 degrees)
  • 3-Protection from water spray from above
  • 4-Protection from splashes from any angle
  • 5-Protection from jets of water from any angle
  • 6-Protection from heavy jets of water from any angle
  • 7-Protection from immersion up to 1m
  • 8-Protection from Immersion past 1m

Methods of Protection 

Frame Choice

Box frames typically leave multiple sides of the coil exposed to the elements. Choosing a tubular frame provides a much greater degree of ingress protection without the development cost of less common features like overmolding or potting. A tubular frame by itself is not enough to prevent moisture ingression but it does provide a degree of protection from solids and dust for the coil.


A “boot” is a flexible neoprene sleeve used to seal the gaps between the plunger and the solenoid coil without restricting the stroke of the plunger.


Exposed connectors and wires represent a significant weak point for moisture ingression. The addition of specialized connectors designed to create water tight seals is vital to reach IP ratings of IP63 or higher.


Plastic overmolding can be used to seal the coil. Overmolding can be used with or without a tubular frame and typically provides IP65 or similar levels of protection.


Filling in the air gaps between the coil and frame with a potting material can create effective protection against ingression. Potting cannot be used in frames with more than 1 open side. Potting typically provides IP65 or similar levels of protection.

Magnet-Schultz of America specializes in the custom engineering and manufacturing of solenoids, solenoid valves, electromagnets, voice coils, hydraulic tubes and coils, and locking devices. If you have any questions related to sourcing or manufacturing, please contact us. We will be happy to assist in the development of your application.


Browse past blogs for a more in-depth look at solenoid functions and subscribe for notifications about future posts!