Technical Help: Leakage Current
Gems Sensors manufactures intrinsically safe and non-intrinsically safe relays for load handling capabilities. On each of the catalog pages there is a column noted as ‘Leakage Current’. Leakage current is when the relay is deenergized, a small portion of current will still travel to the load side. This is in the magnitude of only a few milli amps, but it is important to take note of, especially when using a small load. Typically, no voltage or relay will travel to the load side when the relay is deenergized, hence the term leakage.
When using a small load with these Safe Paks and Load Paks, the leakage current may be enough to energize the load. This can be a problem because then it will indicate that the relay or sensor is always on, which is not technically true. When using loads that require a higher current to turn on, this small leakage current will have no effect.
To counteract this leakage current, a resistor should be installed to take away the current, so it doesn’t get to the load and indicate a false trip. The resistor should be installed on the load side between the load power and neutral, but before the load side. See below image.
The resistor size will depend on the amount of leakage current. Below are some recommendations.
Leakage Current:
- 6mA: 2K 20-Watt Resistor, or 5K 10-Watt Resistor
- 12 mA: 2K 10-Watt Resistor