Ruijie RG-SF2920 Series Hardware Installation And Reference Manual page 25

Hardware Installation and Reference Guide
If a power supply system is equipped with a leakage protector (also referred to as leakage current switch or leakage
current breaker), the rated leakage action current of each leakage protector must be greater than twice the theoretical
maximum leakage current of all the power supplies in the system. For example, if a system is equipped with 16
identical power supplies and the leakage current of each power supply is equal to or less than 3.5 mA, the leakage
current of the system totals 56 mA. A leakage protector with 30 mA rated action current supports less than five power
supplies (that is, Action current of the leakage protector/2/Maximum leakage current of each power supply = 30/2/3.5
≈ 4.28). In other words, the leakage protector with 30 mA rated action current supports no more than four power
supplies. In this case, the 16 power supplies in the system require at least four leakage protectors with 30 mA rated
action current and each leakage protector supports four power supplies. If power supplies in a system differ in models,
the rated leakage action current of each leakage protector divided by two is greater than the sum of maximum leakage
currents of all the power supplies. The rated leakage non-action current of a leakage protector shall be 50% of the
leakage action current. Take a leakage protector with 30 mA rated leakage action current as an example. The rated
leakage non-action current shall be 15 mA. When the leakage current is below 15 mA, the protector shall not act.
Otherwise, misoperation may easily occur due to high sensitivity and thus the leakage protector trips, devices are
powered off, and services are interrupted.
To guarantee personal safety, the rated leakage action current of each leakage protector in the system must be equal
to or less than 30 mA (human body safety current is 30 mA). When twice of the total leakage current of the system is
greater than 30 mA, the system must be equipped with two or more leakage protectors.
For the leakage current value of each product model, see the device model specifications in Chapter 1.
2.1.4 Electrostatic Discharge Safety
To prevent damage caused by static electricity, you must pay attention to the following:
1) Ensure that the grounding screw on the side panel of the device is grounded. Ensure that the AC power socket is a
single-phase three-core power socket with protective earthing conductors (PE).
2) Keep the indoor installation environment clean and free of dust.
3) Keep the indoor humidity within a certain range.
2.1.5 Laser Safety
The RG-SF2920 series switches support various types of optical modules available in the market, and these optical
modules are Class I laser products. Improper use of an optical module may cause damage. Therefore, pay attention to the
following points when using an optical module:
Notes:

When a fiber transceiver works, ensure that the port has been connected with a fiber or covered by a dust cap to
keep out dust and prevent it from burning your eyes.

When an optical module is used on the device, do not look into the transceiver interface of the optical module after
removing the optical fiber. Otherwise, your eyes may be hurt.
Do not approach or stare at any optical port under any circumstances, as this may cause permanent damage to your
eyes.
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Preparations Before Installation