The following tables detail common NPT and metric thread sizes. Metric sizes all share the common format where is the nominal pipe size in millimeters, such that an M6 pipe specifies that the nominal pipe size is 6 mm. For example, a 1/4' NPT standard describes the thread size on a 1/4' pipe. NPT sizes are determined by the nominal size of the pipe or tube. Thread sizes are standardized by the National Pipe Thread (NPT) in North America and metric sizes elsewhere. Mounting Size - The mounting size refers to the size of a strain relief's threads, which are used to connect the strain relief to a junction box or other device. Steel and stainless steel have excellent corrosion resistance and pressure ratings.īuyers of strain reliefs should carefully consider specifications related to the product's size.ĭiameter - A strain relief's diameter refers to the diameter of the cable designed to pass through the product.While each polymer has different characteristics, most have good chemical resistance, flexibility, and versatility. Various types of polymer are used as strain relief materials, including polyester, polyolefin, PTFE, and PVC.Nylon is a synthetic polymer that has similar qualities to brass but is cheaper to buy and manufacture.It typically costs more than other materials. Brass is an alloy of copper and zinc, and features superior strength, ductility, conductivity, and environmental resistance.Aluminum is a light and malleable metal that features excellent conductivity, reflectivity, and oxidation resistance.Strain relief products may be manufactured using different materials, each with its own unique characteristics. Wire Ties, as their name implies, are plastic devices designed to bundle wires, cables, or tubing. Romex Connectors attach to romex cables to seal and support it as the cable enters a junction box or enclosure. Cable glands include a provision for making an electrical connection from the cable to the device.

They serve to secure the end of a cable to a piece of equipment or device. Strain relief types include cable bushings, cable glands, romex connectors, and wire ties.Ĭable Bushings are hollow liners that encircle conductors or cable to provide electrical isolation.Ĭable Glands are also known as cord grips. Flex style strain reliefs create a flexible bend at the connection point, protecting the cable against kinking or breakage. Dome style products are fitted to the cable at the connection point and prevent the cable from rubbing against a rough or sharp edge where the cable meets the device or electrical panel. Strain reliefs can also be classified by style, depending on their flexibility or rigidity. This prevents moisture from entering and possibly damaging the component or machine the cord is connected to. Providing a liquid-tight seal on the cord's connection area. These products keep the cord in a stationary position to prevent the conductors from twisting or pulling. Reinforcement of the cord's electrical connection. This protection is also useful against cutting or fraying by sharp edges of nearby equipment. All strain reliefs serve one or more of three main purposes:Įxtra protection against overbending, which extends the life of the cable. They are manufactured in a variety of sizes and shapes, and using various materials. Strain reliefs protect the lifeline of electrical products by absorbing the forces of push and pull that may be exerted on the flexible wires, cables, or tubing.

Strain relief connector