Rubber Grommet Sizes & Types: Complete Selection Guide

What Are Rubber Grommets?

Rubber grommets are ring-shaped components, typically with a groove around the outer circumference, designed to line the edge of a hole in a panel or sheet material. They serve several critical functions including edge protection, sealing against dust and moisture, vibration dampening, strain relief, and electrical insulation.

Standard rubber cable grommets

Rubber grommets are available in both standard and custom sizes. Standard sizes are defined by inner diameter (ID), outer diameter (OD), and panel thickness. Common measurements range from 3mm to 50mm inner diameter and 8mm to 75mm outer diameter, with panel thicknesses from 1mm to 6mm.

Types of Rubber Grommets

Split Grommets: Have a slit for retrofitting around existing cables without disconnection.

Solid Grommets: One-piece design for maximum sealing, requires cable threading.

Flanged Grommets: Extended lip for additional sealing and surface protection.

Custom Molded Grommets: Fully customized for unique panel thicknesses, cable configurations, or material requirements.

Material Selection for Rubber Grommets

EPDM offers excellent weather and ozone resistance for outdoor use. Silicone provides extreme temperature flexibility from -60C to 230C. NBR (Nitrile) excels in oil and fuel resistance. Neoprene balances weather and oil resistance. FKM/Viton handles the highest temperatures up to 250C with superior chemical resistance.

How to Measure for Rubber Grommets

Accurate measurement is critical. Measure panel hole diameter, panel thickness, and cable bundle diameter using calipers. The rubber grommet inner diameter should be slightly smaller than the cable bundle to create a snug seal. Account for manufacturing tolerances of plus or minus 0.2mm to 0.5mm.

Custom vs Standard Grommets

Choose standard grommets when dimensions match standard sizes and quick availability is needed. Choose custom grommets for non-standard panel thickness, specific material formulations, integrated features, or when certifications such as FDA, UL, or MIL-SPEC are required.

Why Choose Anlintech for Custom Rubber Grommets?

At Anlintech, we manufacture custom rubber grommets to your exact specifications at our ISO 9001:2015 certified facility in Dongguan, China. With over 16 years of experience and in-house mold making, we deliver precision grommets for OEM applications worldwide. Ordering is simple: send your drawings, receive a quote within 24-48 hours, samples in 5-7 days, then mass production.

Learn more about our custom silicone grommets.