PSL PQube - Using External Potential Transformers

PQube User Manual 2.1
Page 16 of 113
Maximum voltages
Connection
Maximum voltage
with respect to Earth
Maximum current
Limitations and remarks
PQube terminals
L1, L2, L3, N
[9] [11] [13] [15]
400 Vrms, CAT III
up to 300Vrms, CAT
IV
Corresponds to 690 Vrms phase-to-phase on centered-
neutral mains systems.
Corresponds to 480Vrms phase-to-phase on centered-
neutral mains systems.
All voltage channels must be covered after installation.
PQube Earth terminal
[32]
N/A
Optional PQube RLY4
terminals [25] [26]
30 Vrms or 60 Vdc
All other PQube
terminals
30 Vrms or 60 Vdc
Optional PS1 terminals
240 Vrms, CAT III
AC voltage input terminal must be covered after
installation.
Optional XCT4 terminals
400 Vrms, CAT III
1 amp for XCT4-1A
5 amps for XCT4-5A
Usually connected to external current transformer
secondaries, which provide insulation from mains.
Corresponds to 690 Vrms phase-to-phase on centered
neutral mains systems.
up to 300Vrms, CAT
IV
Usually connected to external current transformer
secondaries, which provide insulation from mains.
Corresponds to 480Vrms phase-to-phase on centered
neutral mains systems.
Optional CT4 pass-
through inputs
Insulated wire is
required!
400 Vrms, CAT III
20 amps for CT4-20
50 amps for CT4-50
Corresponds to 480Vrms phase-to-phase on centered
neutral mains systems.
up to 300Vrms, CAT
IV
Corresponds to 690 Vrms phase-to-phase on centered
neutral mains systems.
Note: “CAT III” means Measurement Category III as defined in UL / IEC 61010-1: “Measurement category III is for
measurements performed in the building installation…. Examples are measurements on distribution boards, circuit-breakers,
wiring, including cables, bus-bars, junction boxes, switches, socket-outlets in the fixed installation, and equipment for industrial
use…”
“CAT IV” means Measurement Category IV as defined in UL / IEC 61010-1: “measurements performed at the source of the low-
voltage installation…. Examples are electricity meters and measurements on primary overcurrent protection devices and ripple
control units.”
Using your PQube with external Potential Transformers
If you want to measure nominal voltages higher than 690 volts, you can connect your PQube
voltage inputs to the secondary windings (low voltage windings) of any standard Potential
Transformer.
In general, the accuracy of your PQube’s voltage measurements are so precise (roughly ±0.1%) that
any accuracy specification will be determined almost entirely by the potential transformer that you
select. If using calibrated potential transformers, you can enter the calibration constants into your
PQube to further improve your accuracy.
For information on configuring your PQube to read correct voltages when using a potential
transformer, see Setting Your Potential Transformer Ratio (page 28).