Q&A(FAQ) What is meaning of (L) and (N) on AC terminal?
Figure 1 shows how to connect the power supply’s input terminals.
The AC input terminals consist of L (Line) and N (Neutral). Safety standards require the following connections:
- L terminal: Connect to the live (non-grounded) side of the AC mains
- N terminal: Connect to the grounded side of the AC mains
This configuration ensures that, if a ground fault (a short between the AC line and the earth line) occurs inside the power supply, the internal fuse on the L terminal will blow and help prevent electric shock.
The power supply will operate even if the L and N terminals are reversed. However, doing so is not recommended from a safety standpoint because the current path may remain energized during a fault condition (with some product exceptions).
FG Terminal
The FG terminal must always be connected to earth ground, as this is necessary to prevent electric shock.
Using the power supply without grounding the FG terminal may cause changes in characteristics such as:
- Noise terminal voltage
- Ripple noise
Please ensure proper grounding to avoid these issues.
In addition, according to safety standards, our AC-DC power supplies are classified as CLASS I equipment. Therefore, they must be connected to the protective earth terminal of the equipment in which they are installed.
