Riello UPS MASTER HE - Differential (RCD)

0MNMHEM30RUENUB 00 pag. 15 / 57
500-800kVA
In normal operation SWBY and SWOUT switches are closed, the opening of the SWBY change the state of the
neutral output system
500-800kVA
The neutral state is function of position of the bypass line switch.
NOTE (*): place the label supplied (The following label, supplied with the UPS, must be displayed on all
switching devices located upstream in the same electrical system as the UPS):
Before working on this circuit
- Isolate Uninterruptible Power System (UPS)
-Then check for Hazardous Voltage between all terminals
including the protective earth
Risk of Voltage Backfeed
3.1.5 Differential (RCD)
If the MASTER HE protection against electric shock uses differential current devices (RCD), these have to have
the following characteristics:
- Sensitivity 300mA
- sensitive direct current and unidirectional components (class B)
- insensitive to transient current pulses
- delay greater than or equal to 0.1 s.
When operating in the presence of mains supply, a differential breaker (RCD) installed on the input will intervene as
the output circuit is not isolated from the input circuit.
When operating without mains supply (from battery) the input differential breaker will intervene only if it is able to
switch as a result of leakage current without any voltage at its poles (for example a differential breaker with an
auxiliary relay is not suitable). However it is possible to install additional differential breakers on the output of the
UPS, possibly coordinated with those on the input.
L1
N
L3
L2
L1
L2
L3
L1
L2
L3
Static
Switch
SWMB
SWBY
SWOUT
PE
L2
L1
L2
N
L3
N
L3
L1
PE
PE
UPS
(*)