160EET

160EET fuses, also known as E-rated electric time-delay fuses, are an electrical specialty fuse used primarily in higher amperage panels and motor control centers. The primary purpose of the 160EET fuse is overload protection for the circuit, and secondary purpose is short circuit protection. The 160EET fuse is not designed to provide short circuit protection for motors in Class I, Division 2, Group A/B/C/D as defined by NEC Article 501.

The 160EET fuse contains a dual element design, consisting of a very fast-acting element in series with a time-delay element. The fast-acting element detects any short circuit current anywhere from 6 to 10 times the ampere rating of the fuse. The time-delay element delays the operation of the fuse long enough for most large motor starting currents to pass without trouble.

A 160EET fuse can only be used in circuits that have a disconnecting means and the power has to be isolated before changing the fuse. The disconnecting means must meet the requirements of UL Standard 4248-7 and the fuse must be in a UL listed Enclosure. To ensure safety, voltage ratings must be observed and installation should be done by a qualified electrician in accordance with the National Electrical Code (NEC) and local electric codes.

The important thing to remember when using E-rated fuses in a panel or motor control center is to prevent excessive thermal stress in the conductor due to lower fuse withstand rating. A 160EET fuse is ONLY intended for use in motor circuits. A 160EET fuse should NOT be used in branch circuits where it could be subjected to the in-rush current or high cyclic loads of motor circuits. In this case, an E-rated fuse that has a higher temperature rating, such as the 218EET, must be used.

The working principle of the 160EET is also relatively simple. When the current passing through the fuse rises to a level higher than its rated amperage, the fast-acting element of the fuse triggers and shuts off electricity to the circuit. At the same time, the time-delay element of the fuse steps in and prevents quick switching of the fuse on common motor or transformer start-up inrush currents which can harm the circuit.

In summary, the application of 160EET fuse is primarily in panels and motor control centers. The 160EET fuse provides the necessary overload and short circuit protection to the system while also allowing for a current surge when motor and transformers first start up. The main purpose of the 160EET fuse is for overload safety for the connected equipment and for preventing rapid cycling and equipment malfunction. The 160EET fuse must be installed in a UL listed Enclosure and must meet the Disconnect requirements of UL Standard 4248-7.