Different Types of Wire Harness Components

A wire harness is a collection of electrical cables, wires, and subassemblies encapsulated by exterior sheaths that are utilized to connect devices to their power source. The sheaths protect the internal components from physical damage and moisture and keep them organized. Some of the key components of wire harnesses include connectors, terminals, locks, wires, cables, and outer coverings. When selecting a wire harness for your applications, you must take into consideration the capacities of each component to ensure your devices are powered safely. As such, there are several types of wire harness components, all of which we will outline below.


The wire carries the current or signal necessary to power a device, and the wire’s capacity must meet or exceed the voltage or bandwidth it is expected to transmit. Generally, wires are made of copper and are equipped with a specialized coating.


Wire connectors are designed in several varieties and sizes to suit a myriad of wire types. While they are usually made of plastic, they can also be made of metal and ceramic.


Fuses are tasked with stopping power surges from overloading or damaging devices on the receiving side of the fuse. While different harnesses utilize different classes of fuses, they are generally rated for 32 volts or less and vary according to their amperage rating.


Grommets are insulators that prevent moisture from building up in the connector and can be attached with the terminal or can be a part of the connector.

Outer Coverings/Insulators

Also called tubes and sleeves, insulators provide abrasion resistance, environmental protection, and protection from electrical shock. They are available in a variety of materials, with the most common being nylon or polyolefin.


Relays switch higher amperage circuits ON or OFF, allowing harnesses to power multiple things. Similar to fuses, they differ based on amperage requirements.

Strain Relief

This component is usually added to the outside of the connector and prevents the wires in the connector from being pulled out of it.


Terminals are the metal components that are affixed to the end of the wire and inserted into the connector or attached to a point on the connecting equipment.


Cable ties and clamps ensure that the wires in the harness remain attached in a particular direction. Additionally, they can be utilized to minimize movement.


Locks are inserted into a connector to prevent the terminal from being pulled out of the connector. More than that, they also ensure the complete insertion of the terminal.

Wire Harness Applications

Wire harnesses find use in almost every industry, ranging from aerospace, automotive, and electronics to household appliances, manufacturing, and refrigeration. That being said, there are some component qualities to consider when making a selection. For example, you should take the type of wire, length, gauge, material, voltage and current capacities, sheath, conductor, insulation material, environmental capabilities, and more into consideration.


ASAP Fasteners is a leading distributor of harness components, all of which have been sourced from top global manufacturers that we trust. With over 2 billion new, used, obsolete, and hard-to-find items in our inventory, customers can easily fulfill their operational needs. Backed by rapid lead times and unbeatable cost savings on thousands of products, ASAP Fasteners is ready to serve as your strategic sourcing partner. As an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited business, customers can trust in the integrity of our offerings as we only source items from entities on our Approved Vendor List (AVL).

Peruse our expansive catalogs at your leisure and take advantage of our search engine and filters to narrow down our listings with ease. Once you find an item that sparks your interest, fill out and submit a Request for Quote (RFQ) form, and within 15 minutes of submission, an expert team member will reach out with a customized solution. For additional questions, call or email us at any time; we are available 24/7x365!


Recent Twitter Posts