There are countless types of cable grommets available, making it challenging to select the right one for your specific application.
Choosing the wrong grommet can lead to issues like poor cable protection, water and debris ingress, EMI interference, and production delays.
In this guide, we’ll break down the major types of grommets including open, closed, membrane entry, diaphragm, stepped, strips and specialty models to help you make an informed choice for your project.
Open Grommets
Open grommets, also known as U-shaped grommets, are the most basic type of grommet. They feature an open design that allows for easy insertion and removal of wires or cables. Open grommets are typically used in applications where the wires or cables need to be frequently accessed or replaced.
Closed Grommets
Closed grommets, in contrast to open grommets, have a closed design that completely surrounds the wires or cables. This type of grommet provides better protection and strain relief compared to open grommets. Closed grommets are further categorized into two sub-types: blind grommets and semi-blind grommets.
Blind Grommets
Blind grommets have a closed back, meaning the wire or cable cannot pass entirely through the grommet. Instead, the wire or cable is inserted through the front opening and terminates within the grommet. Blind grommets are ideal for applications where the wire or cable needs to be completely sealed and protected from the external environment.
Semi-blind Grommets
Semi-blind grommets have a partially closed back, allowing the wire or cable to pass through the grommet while still providing a degree of protection. The semi-blind design offers a balance between the protection of a blind grommet and the accessibility of an open grommet.
Membrane Entry Grommets
Membrane entry grommets feature a thin, flexible membrane that seals around the wires or cables as they pass through the grommet. This design provides an additional level of protection against dust, moisture, and other environmental contaminants. Membrane entry grommets are commonly used in outdoor or harsh industrial applications.
Diaphragm Grommets
Diaphragm grommets have a flexible, rubber-like material that stretches to accommodate wires or cables of various sizes. The diaphragm material creates a tight seal around the wires, preventing the ingress of dust, moisture, and other contaminants. Diaphragm grommets are versatile and can be used in a wide range of applications.
Stepped Grommets
Stepped grommets have multiple levels or steps that allow for the organization and separation of wires or cables. Each level can accommodate wires or cables of different sizes, making stepped grommets ideal for applications with multiple wires or cables passing through a single opening.
Grommet Strips
Grommet strips are long, continuous pieces of grommet material that can be cut to the desired length. They are designed to protect the edges of larger openings or slots where multiple wires or cables pass through. Grommet strips provide a clean, organized appearance while protecting the wires from damage.
Specialty Grommets
In addition to the standard types of grommets, there are also specialty grommets designed for specific applications or environments.
Brush Grommets
Brush grommets feature a dense brush material that allows wires or cables to pass through while maintaining a seal against dust and debris. The brush material also helps to minimize electromagnetic interference (EMI) and radio frequency interference (RFI), making brush grommets suitable for use in electronic equipment.
EMC Grommets
EMC (electromagnetic compatibility) grommets are designed to provide shielding against electromagnetic interference. They are made from conductive materials, such as metal or metallized plastic, and are used in applications where EMI must be minimized to ensure the proper functioning of electronic equipment.
Split Multi Grommets
Split multi grommets have multiple openings to accommodate several wires or cables in a single grommet. The split design allows for easy installation and removal of the wires or cables without the need to disconnect them. Split multi grommets are useful in applications where multiple wires or cables need to be routed through a single opening while maintaining organization and protection.