Hardware Installation
2. Preparation before Installation
82
www.qtech.ru
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 power supply model, see the power supply model
parameter table in Chapter 1.
2.2.8
System Grounding Requirements
A good grounding system is the basis for the stable and reliable operation of the QSW-7600. It
is the key to prevent lightning stroke and resist interference. Please carefully check the
grounding conditions on the installation site according to the grounding requirements, and
perform grounding properly as needed.
Safety Grounding
The equipment using AC power supply must be grounded by using the yellow/green safety
grounding cable. Otherwise, when the insulating resistance decreases the power supply and
the enclosure in the equipment, electric shock may occur.
The building installation shall provide a means for connection to protective earth, and the
equipment is to be connected to that means.
Lightning Grounding
The lightning protection system of the facility is a separate system that consists of the lightning
rod, down lead conductor and the connector to the grounding system, which usually shares
the power reference ground and yellow/green safety cable ground. The lightning discharge
ground is for the facility only, irrelevant to the equipment.
For lightning protection, see Appendix B.
EMC Grounding
The ground required for EMC design includes shielding ground, filter ground, noise and
interference suppression, and level reference. All the above constitute the comprehensive
grounding requirements. The grounding resistance should be less than 1
Ω
. One grounding
point is reserved at the left back of the chassis. The grounding point is pasted with a
conspicuous warning label.
2.2.9
EMI Consideration
Various interference sources, from either outside or inside the equipment or application
system, affect the system in the conductive ways such as capacitive coupling, inductive
coupling, and electromagnetic radiation. There are two types of electromagnetic interferences:
