Electrical Engineering; Requirements External Rcd/Gfci - ABB Terra DC wallbox Installation Manual

2.3

Electrical engineering

The electrical installation must be completed according to the local safety and electrical
regulations and laws.
In general, the installer should follow the following prescriptions for the electrical installation
of the devices upstream the installation.
IEC prescription:
- Installation of charging stations must be according to IEC 60364-7-722 and/or any
applicable national rules
-
Each charging station must be individually protected via a separate upstream RCD
(Residual Current Device) at least of type A with a rated residual operating current
not exceeding 30 mA.
- As all variant have an internal a DC fault current monitoring function, a DC fault cur-
rent over 6 mA does NOT occur on the AC-input side of the TERRA DC WALLBOX, and
thus an upstream RCD of type B is not required, nevertheless local regulation could
require a RCD of Type B independent of internal DC fault current limitation
NOTE. According to the standard for RCDs, type A RCDs are able to tolerate 6 mA of
DC fault current while still maintaining their correct functionality.
- Fuses or equivalent circuit breaker rated to respect the charger specifications must
be used (ref. cfr 16.1, IEC 61851-1:2017)
North American prescriptions:
- Each charging station must be connected via a separate GFCI (Ground Fault Circuit
Interrupter /or equivalent RCD device) for the personal protection from the hazard of
electric shock. The protection must be proven to withstand the presence of DC cur-
rents >6mA not blinding the leakage detection (type B RCD or equivalent leakage de-
tection)
-
Fuses or equivalent circuit breaker rated to respect the charger specifications must
be used
2.3.1

Requirements External RCD/GFCI

DC-charging side requires immunity for short current peaks over PE
When the charger engages the DC charging (at the beginning of every charger session in
the pre-charge phase) a relay switches and turns on the input to the power modules. A
synchronic engagement of the phases in the relay in combination with the electrical ca-
pacity in the input power part, can cause incidental very short (25 microseconds) current
peaks of up to 60A over the Protective Earth. The amplitude of the Ampere peaks can
vary with the location and is dependent on grid and earth impedance. Given the switch-
ing characteristics of the DC section of the charger we give you the advice to select an
2 2 -O CT -19
NOTICE
External RCD/GFCI not included in delivery scope
Upstream RCD/GFCI's are explicitly excluded from ABB's
delivery scope and belong to the scope of the installation
company. The locally certified installation company can base
the RCD/GFCI device type, amongst other external factors,
on below charger characteristics.
T ERRA D C WA LLBO X
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