APC GALAXY 7000 - Manual (Page 25)

System earthing arrangements >
34020846EN/AD - Page 25
1. Installation
TNC upstream, TNC, TNS or TT downstream installation
For separate normal and bypass AC lines from a single source.
IT upstream, IT downstream
For separate normal and bypass AC lines from a single source.
Parallel UPSs systems
Earthing system adaptations are the same as those previously detailed for unitary UPS.
It is essential to transform the UPS internal PE bar into a PEN bar, See “Adapting the cabinet according to the neutral point
connection”, page 26.
For an installation with a SSC cabinet or an external bypass cabinet, it is essential to transform the cabinet's internal PE
bar into a PEN bar, See “Adapting the cabinet according to the neutral point connection”, page 26.
Unit or modular UPS
The UPS output neutral must be connected to the internal PEN bar (1)
Parallel UPS with SSC cabinet or modular UPSs with external bypass cabinet:
The SSC cabinet output neutral or external bypass cabinet output neutral must be connected to the internal PEN bar for
this cabinet.
The connection between the UPS outputs and the SSC cabinet or the external bypass cabinet must be done in TNC
(connect the PEN cable to the PEN bar).
The load neutral terminal on the UPS, SSC or external bypass cabinet must not be used.
The SLT downstream TNS or TT starts on the MGE ™ Galaxy™ 7000 installation output.
In normal operating mode
The CPI1 controls the whole installation including downstream from the UPS. Power to the CPI2 is switched off by the R2
relay which controls voltage presence upstream from the UPS.
If the voltage is cut or the protection is opened upstream:
The R1 relay cuts the CPI1 circuit and the R2 relay closes the CPI2 circuit thus maintaining control downstream of the UPS.
Bypass AC
Normal AC
L1
L2
L3
L1
L2
L3
N
L1
L2
L3
N Q4S
1
Load
PEN
SS
UPS
PFC INV
MLVS
PEN
PEN
PE or PEN
NP:Not Provided NP
Bypass AC
Normal AC
L1
L2
L3
L1
L2
L3
N
L1
L2
L3
N
R1
R2
CPI2
CPI1
Load
PE
SS
UPS
PFC INV
MLVS
PE
IMD2
IM
D