To check whether the terminal voltage is good or not, professional testing equipment is required. Common terminal detection equipment includes terminal section analyzer (MQ-200E) UL is the abbreviation of Underwriter Laboratories Inc. UL certified terminals are wiring terminals that have passed the UL safety test. Some terminals have passed the UL safety test. They are the most authoritative in the United States and the largest non-governmental institutions engaged in safety testing and identification in the world. It is an independent, non-profit, professional organization that conducts experiments for public safety. It uses scientific testing methods to study and determine whether various materials, devices, products, equipment, buildings, etc. are harmful to life and property and the extent of harm; Determine, prepare and issue corresponding standards and materials that can help reduce and prevent loss of life and property, and conduct fact finding business.