UL is a shorthand for Underwriter Laboratories Inc. The  UL Safety Laboratory is the most authoritative in the United States and  a large private institution engaged in safety testing and  identification. It is an independent, non-profit, professional organization that tests for public safety. Its  business includes: experiments on materials, tools, products,  equipment, construction, methods and systems to assess whether the  safety of people's lives and property is compromised.
The  process of setting standards for UL: research on the market demand of  products; writing materials for the organization; submitting ANSI, and  organizing the first draft of the research; submitting the first draft  of the standard to ANSI again, waiting for the ANSI approval to be the  official standard, and the general standard setting period is 1-2 years. For products without standards, the general approach is: 1. Find the corresponding product standards and adopt other product standards; 2. Set new standards right away. On the whole, it is difficult for the development of standards to keep up with changes in the market.
UL certification type division
UL's product certification and testing services are mainly classified into listing, recognition and grading.
1)  LISTED: Generally speaking, the column name is only applicable to the  complete product and various devices and devices that are qualified or  replaced by the qualified personnel. The various products belonging to  the UL listing service include: household appliances ,  medical equipment, computers, commercial equipment, and various types  of electrical products that function in buildings, such as power  distribution systems, fuses, wires, switches, and other electrical  components. UL listed products can usually be marked with a UL listing mark on each product. The use of the listing symbol.
2)  Recognized: An accredited service is a project in the UL service. The  products it identifies can only be used as components and raw materials  in UL listings, grading or other approved products. The  approved product is not structurally complete or has certain  limitations in its use to ensure the expected safety performance. In most cases, the tracking service for approved products falls into the R category. Approved  products belonging to Class L are electronic wire (AVLV2), machined  wire (ZKLU2), wire harness (ZPFW2), aluminum wire (DVVR2), and metal  flexible pipe (DXUZ2). Approved product requirements are marked with an approval.
3)  Classification: The classification service only evaluates the specific  hazards of the product, or evaluates products that implement other  standards than the UL standard (including internationally recognized  standards such as IEC and ISO standards). In general, most graded products are not products used by consumers, but products used industrially or commercially. The  grading mark in the UL Mark indicates that the product has certain  restrictions and specified ranges when it is UL-approved. For  example, a chemical such as a solvent used in the industry only  evaluates the range of fires that may occur when the ignition  temperature is reached. Some  products have the same grading service and listing service, but  generally only evaluate one aspect or several aspects of the product.  For example, in the United States, medical X-ray diagnostic equipment  must comply with US laws and related radiation emissions and beams. Flow  accuracy is specified, but since UL only uses X-rays as a graded  product, only its mechanical, electrical, and other non-radiative  properties are evaluated.
4)  Multiple listing, multiple approval or multiple grading services: When a  UL applicant obtains the above listed, approved or grading services,  its products are to be produced in the name of another company to meet  the needs of sales, you can apply Multiple  listings, multiple approvals or multiple grading services, in which  case the manufacturer that is listed, approved or graded is allowed to  use the name of another company in the product list, except for the  company code, product code or In  addition to other features that UL believes are acceptable, it must be  consistent with the original listed, approved or graded product.
5)  "AL" listing, accreditation or grading service: If a UL applicant does  not want to obtain listing, accreditation or grading services in the  name of his company, he may apply for another name (usually a retailer  or wholesaler) Application for listing, recognition or grading, ie "AL" listing, accreditation or grading services. It  differs from multiple listings, multiple recognitions, or multiple  rating services in that the applicant is not a listed person.
UL certification process
Product application for the UL Mark includes the following steps:
1. Applicant submits relevant company and product information
Written application: You should request UL to test your company's products in writing.
Company  Information: Provide detailed and accurate names, addresses, contacts,  zip codes, telephone numbers and faxes in the following units in both  Chinese and English.
(a).  Application company: A company that submits a product testing  application and is responsible for all engineering service fees.
(b). Listed companies: companies whose names are listed in various product catalogues published by UL
(c) Production plant: The manufacturer and producer of the product.
Product Information: Product information should be provided in English.
(a). Name of the product: Provide the full name of the product.
(b). Product model: List all the product models, varieties or classification numbers that need to be tested.
(c). The intended use of the product: for example: home, office, factory, coal mine, ship, etc.
(d).  Parts list: List the parts and models (classification numbers), the  rating, and the name of the manufacturer that make up the product. For insulating materials, please provide the name of the raw material, for example: GE Polycarbonate, Lexan Type 104. When  the component has obtained UL certification or recognition, please  prove the specific model of the component and indicate its UL file  number.
(e) Electrical properties: For electronic and electrical products. Provide electrical schematic (circuit diagram), electrical performance table.
(f).  Structure diagram: For most products, it is necessary to provide  structural drawings or explosion diagrams, ingredient lists, etc. of the  product.
(g). Photographs of the product, instructions for use, safety, etc. or installation instructions.
2. Product testing
Product  testing is generally performed in UL laboratories in the United States,  and UL can also accept audited participation in third-party testing  data. The experimental samples will be returned or destroyed according to your requirements. If  the product test results meet the requirements of the UL standard, UL  will issue a test report and follow-up service (FollowUp Service  Proccdure) test report will detail the test situation, the sample  reached the index, the product structure and the safety signs suitable  for the use of the product. A description of the product and instructions for the UL Regional Inspector are included in the Tracking Service Rules. A  copy of the test report is sent to the applicant company and a copy of  the tracking service details is sent to each production facility.
3. The applicant is authorized to use the UL mark
The  UL Regional Inspector in China contacts the production facility for the  Initial Production Inspection (IPI). The inspector checks the condition  of your products and their parts in the production line and warehouse  inventory to confirm the product structure and parts. The  tracking service rules are consistent. If required by the rules, the  regional inspector will also conduct a witness test. When the inspection  result meets the requirements, the applicant is authorized to use the  UL mark.
After  the IPI, the inspectors will go to the factory to check the product  structure and conduct the sighting test from time to time. The frequency  of inspection is determined by the type of product and the quantity of  production. Most types of products are inspected at least four times a  year. The inspectors are inspecting Ensure  that the product continues to be consistent with UL requirements.  Please notify UL before you plan to change the product structure or  components. For minor changes, you do not need to repeat any  experiments. UL can quickly modify the tracking service rules so that  inspectors can accept This change. When  UL believes that a product change affects its safety performance, it is  necessary to apply for a company to resubmit the sample for necessary  testing.
The cost of tracking the service is not included in the test fee.
If  the product test results do not meet the UL standard requirements, UL  will notify the applicant to explain the problems. After the applicant  improves the product design, the product can be re-inspected. You should  tell the UL engineer what improvements have been made to the product so  that it can decide It is the step to apply for UL certification.
UL certification inspection rules
The UL inspector's inspection is basically a mechanical operation. Depending  on the product, the inspector's inspection is based on Bulletin,  Procedure, FUII (if included, included in the Bye-Law) and UL Standard  (if requested in FUII).
If  the inspector visits the factory and the factory is producing UL  products, or stocked UL products, the inspector will sample the samples  in one of the following ways:
1. Extract each part from the production line plus a complete product extracted from the warehouse.
2. Extract individual parts from the warehouse plus complete products on the production line.
3. Extract the complete product from the warehouse for splitting.
The  exact number of samples is determined by the rules, FUII (Tracking  Inspection Instructions), SAP (Standard Attachment) or direct orders  from the UL Laboratory. Inspectors  do not necessarily inspect all products at each inspection, but they  will try to inspect all product categories or models within one year or  at least two years.
Generally  speaking, UL's requirements for the factory production system are not  too high. It is only required to measure the equipment once a year, save  the factory's own inspection records, and have certain control measures  for the non-conforming products.
At  the time of inspection, the on-site representative (UL inspector) will  focus on the product itself, and they will check the structure,  components and assembly of the product one by one according to the above  inspection basis. For  parts related to product safety, the general rules specify the  requirements for UL-certified products, and will indicate the  manufacturer and model; for shells, shields and other injection molded  parts, the general rules will specify the raw materials and size  requirements. The on-site representative will check the UL mark as specified in the above items and rules.
In  addition, if the specification or FUII or standard requires on-site  testing of the product, the site representative will ask the factory  inspector to do the corresponding tests, while the on-site  representative will witness it. If  the rules also require the sample to be sent to UL for tracking test,  the factory shall cooperate with the inspector to produce the  corresponding sample. After the inspector writes the sample label,  provides the address and seals the sample, the factory sends it to the  corresponding UL laboratory.
If  the products produced by the factory fully comply with the requirements  of the corresponding UL inspection standards and there is no other  violation of the tracking service agreement, the inspector will issue an  inspection report (Inspection Report); the factory representative  should report on the report after confirming that the content is  correct. Signature; one test is completed. If  there is a non-compliance with the inspection standard during the  inspection, the inspector will issue a Variation Notice and take  appropriate measures according to the specific circumstances.
In  the case of unauthorized use of the UL mark, the inspector will request  removal of the UL mark; for products that do not meet UL requirements,  the inspector will require the factory to remove the UL mark or rework  to meet the requirements; if the factory disagrees with the above  treatment, then Temporarily  retain the UL mark, but must stop the shipment, the inspector will  inform the appropriate laboratory, the UL will reply to decide whether  the UL mark can be retained; if there are only some minor problems, it  does not affect the safety of the product, The  inspector will make a provisional acceptance decision and report it to  the appropriate laboratory; if there are some obvious standard errors,  such as typing errors or unit errors, it will not affect the conformity  of the factory products, but as a UL document, The inspector will also issue a notice of change. Under  normal circumstances, unless it is the responsibility of UL, the  inspector will ask the factory to explain the non-conformity to the  corresponding laboratory, UL will respond accordingly according to your  explanation.
Of course, the inspector's judgment is only temporary, and the final decision is of course in UL laboratories. If  the factory disagrees with the inspection method, it can be fully  reflected to the corresponding laboratory. At this time, the inspector  is obliged to provide the corresponding contact person and contact  method. The factory representative shall sign the notice after confirming that the contents recorded in the change notice are correct.
UL certified factory inspection
The  UL Regional Inspector in China contacts the production plant for the  Initial Production Inspection (IPI). The inspector checks the condition  of your products and their parts in the production line and warehouse  inventory to confirm the product structure and parts. Consistent with the Tracking Service Rules, the District Inspector will conduct a witness test if required by the Rules. When the inspection results meet the requirements, the applicant is authorized to use the UL Mark.
After  the IPI, the inspectors will go to the factory to check the product  structure and conduct eye test experiments from time to time. The  frequency of inspections is determined by the type of product and the  volume of production. Most types of products are inspected at least four  times a year (the cost of tracking services is not included in the cost  of the test). The  inspector's inspection is to ensure that the product continues to be  consistent with UL requirements, and you are required to notify UL  before you plan to change the product structure or components. For  minor changes, there is no need to repeat any experiments, and UL can  quickly modify the tracking service details so that the inspector can  accept the changes. When  UL believes that a product change affects its safety performance, it is  necessary to apply for a company to resubmit the sample for necessary  testing.
UL certification tracking inspection
As  an integral part of UL certification, UL has established a "tracking  inspection" system to ensure that UL's listing and approved products  continue to meet UL standards and requirements. "Tracking  inspection" is the inspection and inspection of UL products by UL's  field representatives distributed around the world to the local factory  production site. The  purpose is to verify the manufacturer's production process, inspection  process and products by verifying the factory's production process,  inspection process and products, in accordance with UL standards and  tracking inspection rules.
UL is a shorthand for Underwriter Laboratories Inc. The  UL Safety Laboratory is the most authoritative in the United States and  a large private institution engaged in safety testing and  identification. It is an independent, non-profit, professional organization that tests for public safety. Its  business includes: experiments on materials, tools, products,  equipment, construction, methods and systems to assess whether the  safety of people's lives and property is compromised.
The  process of setting standards for UL: research on the market demand of  products; writing materials for the organization; submitting ANSI, and  organizing the first draft of the research; submitting the first draft  of the standard to ANSI again, waiting for the ANSI approval to be the  official standard, and the general standard setting period is 1-2 years. For products without standards, the general approach is: 1. Find the corresponding product standards and adopt other product standards; 2. Set new standards right away. From