Six reasons you fail Low Voltage Directive (LVD) compliance testing

Every year, many products fail during the Low Voltage Directive (LVD) testing right when they are close to being released or may even already be on the EU market. That is because manufacturers perceive LVD safety testing as much simpler compared to the EMC testing. They should not ignore it or take it lightly because it relates to the product safety and user health. If the product electrical safety is questionable, then the consequences could be fire or even explosion.

Most of the times when a product fails its Low Voltage Directive (LVD) testing it’s because some modification or any other qualification of documentation is not present, and it needs to be in order the product to be considered as CE compliant. However, that’s not always the case, and instead of being so complicated, the problem could be quite easier to solve. There are six other causes of failure, which if manufacturers keep in mind can help them ensure their subsequent LVD product compliance testing will go smoothly and without any problems:

• Single fault testing: It relates to the insufficient or incorrect protection of electrical circuitry which can lead to overheating, fire or breakdown of insulation during single fault testing
• Protection of batteries (in particular lithium cells): In this case, some protection components, such as lithium cells, are either missing or insufficient for the battery capacity, and it can lead to over-charge and over-discharge.
• Temperature rise: When a product is tested, its isolation transformers, PCBs or any other of its components are operating above the permissible limits of the test standard or the specific component standard. The consequences of this could be in a derogation of insulation property over a period which could, in turn, lead to an electric shock hazard.
• Creepage and clearance: Often overseen by the PCB designers, if the circuit is controlling something on the primary side of the electrical equipment, i.e. a motor or a heater, via a relay/optocoupler, then the creepage and clearance become quite critical.
• Component approval: It relates to the lack of particular information, in most cases safety standards such as EN or IEC standard. Sometimes, the cause of failure also can be because the information is expired or the test specification is withdrawn.
• Marking and instructions: Marks related to the electrical ratings or any other warning marks, placed on the equipment, are incorrect or insufficient. Moreover, a fail during an LVD test can occur if there is inadequate information or technical explanation regarding how the electrical equipment should be used, installed and serviced.