BATTERY LINE
A protection device against overcurrents and an isolating device must be envisaged on the UPS battery line.
The size/type of protection fuse must be chosen based on the capacity of the battery box installed, referring to
the table below.
External DC protection devices
Type of fuse
Fuse size
gl / gG NH
2
x
the battery capacity in Ah
aR NH
2.5 x the battery capacity in Ah
For example: 150Ah-type batteries can use the following fuses: 250A type gl/gG or 315A type aR
Caution, it may be necessary to increase the battery fuses in the event of very short autonomy times.
Before opening the fuses/isolating switch present on the battery box, make sure that the UPS is off.
OUTPUT FUSES
Output protection devices (recommended values for selectivity)
Normal fuses (GI)
Ir (Rated current)/7
Normal switches (C-Curve)
Ir (Rated current)/7
Ultra-fast fuses (GF)
Ir (Rated current)/2
RESIDUAL CURRENT DEVICE
In the standard version, without an input separation transformer, the neutral originating from the mains is connected to
the UPS output neutral. The system neutral point treatment is not modified:
THE INPUT NEUTRAL IS CONNECTED TO THE OUTPUT NEUTRAL
THE DISTRIBUTION SYSTEM WHICH POWERS THE UPS IS NOT MODIFIED BY THE UPS
The neutral point treatment is only modified if a barrier is present or when the UPS operates with the neutral
isolated upstream.
Ensure the correct connection of the input neutral because its absence could damage the UPS.
When operating with mains voltage present, a residual current device may intervene because the output circuit is not
isolated from the input circuit.
In any case, it is always possible to insert further residual current devices on the output, where possible coordinated with
those present on the input.
The residual current devices located upstream must have the following characteristics:
residual current adequate for the sum of UPS + load; it is advisable to allow a suitable margin in order to avoid
inopportune interventions (500mA min) *
type B or type A
delay greater of equal to 0.1s
*
The load leakage current is added to that of the UPS on the earth protection conductor.
