Issue 1.2 May 2020
EVSE Protocol Controller 2.0 (EPC 2.0) | Viridian EV
6
3.3 EPC 2.0
PEN LOSS DETECTION SYSTEM
In the event of a fault in the PEN conductor supplying the property the Protective Earth terminal may become live and as such
carry potentially dangerous current.
For
single phase charge points only*
the EPC 2.0 can protect the user in the event of an open PEN conductor in the power
distribution network. In the event of a fault in the PEN conductor the EPC 2.0 will disconnect all conductors including the pro-
tective earth conductor.
The device measures earth current (using supplied current transformer (CT)) and voltage (between Live and Neutral); either
measurement outside of the factory set limits will cause a fault condition which will cause the EPC 2.0 to open the EV and Aux
contactors, isolating the EV and disconnecting all conductors including the PE conductor, meeting minimum requirements in
BS 7671: 2018 amendment 1, 722.411.4.1 (iv) and (v).
A single pole isolation contactor with a 240V coil rated for the nominal EVSE load is required to disconnect and isolate PE for
this functionality to work.
Details regarding the connections of the EPC 2.0 and the CT can be found in the Terminal Assignment table (6.2) and the Wir-
ing example (6.3)
Important note: Single phase & 3 phase installations
Full PEN Loss detection functionality in the EPC 2.0 has been designed in accordance with UK specifications (BS 7671: 2018
amendment 1, 722.411.4.1 (iv) and (v)) for
single phase charge points only*.
The EPC 2.0 complies with paragraph BS 7671:2018 amendment 1, section 722.411.4.1 paragraph (iv) for single phase installa-
tions by monitoring the supply voltage. If this is outside of limits (207
-
254 V) the device will open both relay contacts thereby
isolating the charge point socket from the mains network, including the earth path.
Additionally, the device complies with paragraph (v) of the above section as the PEN Loss CT is designed to sense this fault
current in the earth conductor and open both relay contacts thereby also isolating the charge points socket from the mains
network, including the earth path.
It is up to the user creating the EVSE using an EPC 2.0 to understand if it is a single phase or three phase installation and apply
the requirements of BS 7671: 2018 amendment 1 accordingly.
It is up to the user creating the EVSE using an EPC 2.0 to know and understand their local regulations outside the UK and
whether this device suitably protects against an open PEN conductor situation in the distribution network.
*
If the PEN Loss CT is still connected and PEN Loss is enabled, the device will still open the contactors and isolate the charge
point socket for the 3 phase charge points (meeting paragraph (v) of the above specification), however full PEN Loss detection
has been designed to meet both paragraphs (iv) and (v) of the above specification and not all live conductors are being meas-
ured in a 3 phase charge point by the EPC 2.0.
