The basic building blocks of an indoor LED display are LED lamp beads and driver chips, both of which are high-precision microelectronic devices. The operating voltage of LED lamp beads is typically 5V with an operating current less than 20mA. These low-voltage, low-current operational properties make them extremely susceptible to static electricity and spontaneous voltage or current fluctuations, as well as comparatively poor resistance to foreign interference. Safety protection measures must thus be exercised in production, installation, and usual use, and power grounding is the most important action for guaranteeing safe and reliable operation.

The need for grounding is closely connected to the operating mode of switching power supplies employed in LED displays. The power supplies are sophisticated devices of energy conversion that work to convert AC 220V grid voltage into steady DC 5V output, which powers the LED lamp beads and driver chips. Conversion is carried out in several steps, such as filtering, rectification, pulse modulation, and output rectification. To provide stability throughout the process, manufacturers are required to follow national 3C standards by incorporating EMI filter circuits into the AC input. The circuits link the live wire to the grounding wire and thereby avoid power grid noise interference and stabilize the input voltage. But this structure automatically introduces leakage current.

In the normal state, one switching power supply generates about 3.5mA leakage current, and the leakage voltage can reach 110V. This kind of leakage current can't be safely discharged if the LED display is ungrounded. In light cases, this can burn out LED lamp beads or damage driver chips. For bigger screens with 20 or more power supplies, the leakage current will sum up and likely be greater than 70mA — sufficient to cause a leakage protector to trip and cut off power without notice. That is why leakage protectors are generally not used in LED display systems.

The risks are even increased when no leakage protector is fitted and the screen is not earthed. Under these conditions, the total leakage current can exceed the human body safety threshold of 10mA and the leakage voltage of 110V is dangerous enough to cause a serious electric shock as well as harm to life.

Proper grounding removes these risks in a proper manner. Once a power supply is properly grounded, leakage current is correctly shunted to the ground by the use of the ground wire. This minimizes the difference in potential between the casing of the power supply and the human body to practically 0V, stopping component failure resulting from leakage and completely removing the risk of electrical shock.

In summary, earth grounding the power supply of indoor LED displays is not simply compliance — it is a critical step that provides system stability, shields sensitive electronic components from grounding, and provides human safety.