EXS
User Manual 10H52260UM60 - Rev. 1 - 10/2017
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1. The protective earth cable dimension shall be selected according to the AC power failure level, cable length and
protection type. The grounding wire connection must use the shortest possible connection route.
2. In the case of cables that are required to handle large current, it may be easier to use multiple smaller cables in
parallel.
3. When selecting the battery cable dimension, it is important to take the current value in Table 3-1 into account and
bear in mind that the maximum permissible voltage drop is 4 Vdc.
4. Avoid coiling the cables as this would increase the electromagnetic interference (EMI).
Power Cable Connecting Terminal
The rectifier input, bypass input, output and battery power cables are connected to the corresponding terminals, as
shown in Figure 3-2.
Protective Earth
The protective earth cable must be connected securely to the PE input terminal (see Figure 3-2) using the fastening
bolt. All the cabinets and cable troughs shall be earthed according to the local regulations. The earthing wires shall
be secured in order to prevent them coming loose from the fastening screws if they are pulled.
Warning
Failure to earth the various elements as directed may result in EMI, electric shock or fire risk.
External Protective Device
To ensure safety, it is necessary to install external circuit breakers on the UPS input and battery lines. Because no
two installations are the same, this section is only intended to provide general practical guidelines for installation
engineers. Qualified installation engineers should be aware of the local wiring regulations and any other related
information
Rectifier and bypass input power supply
1. Input overcurrent and short circuit protection
Install suitable protective devices on the mains input supply distribution line. The protective devices should provide
functions such as overcurrent protection, short circuit protection, isolation protection and tripping upon backfeed.
When selecting the protective devices, consider the power cable current-carrying capacity, system overload
capacity (see Table 10-6 and Table 10-7) and the short circuit capacity of the upstream power distribution.
2. Split bypass configuration
If the UPS adopts the split bypass configuration, independent protective device shall be installed on both the
rectifier input and bypass input distribution lines.
Note
1. The rectifier input and bypass input must use the same neutral line.
2. In the case of IT grid systems, a 4-pole protective device must be installed on the UPS external power distribution line.
3. Earth fault protection
If the upstream input power supply his fitted with an RCD, it is important to take the transient state and steady state
earth leakage current upon the start-up of the UPS into account.
The RCCB shall meet the following requirements:
Be sensitive to DC unidirectional pulses (class A) in the power distribution network
Be immune to transient current pulses
Have an average sensitivity of 0.3A - 3A (adjustable)
The RCCB symbols are shown in Figure 3-1.
