What is the phone number for new jersey manufacturers insurance? New Jersey Manufacturers Contact Phone Number is : 1-800-232-6600. New Jersey Manufacturers Insurance Company (NJM) offers the huge range of insurance policies to the people such as commercial auto, workers' compensation, flood and many other types of insurances. Headquartered in West Trenton, New Jersey, the company was established in 1913.What is nj manufacturers insurance code? Phone Number of Nj Manufacturers is +1-800-232-6600, Fax No: +1-609-882-3457 . NJ Manufacturers originally known as New Jersey Manufacturers Insurance Company, also known as NJM, is an American insurance company that offers different kinds of insurance and financial services to the people of the United States.What is new jersey manufacturers insurance? NJM Insurance Group, originally known as New Jersey Manufacturers Casualty Insurance Company, formed as a workers’ compensation insurance company during the early 1900s, when industrialization in America was at its peak. The Company grew, expanding to auto insurance soon after being established in 1913.