Checking a CP contact

Checking a CP contact

Risk to life due to electric shock

There is a risk of electric shock when working on the electrical installation of the EV charging box. All work which requires the EV charging box to be opened may be carried out only by an electrician.

Also observe the documentation for the EV charging box (assembly instructions and operating manual). You can download the documents in the product catalogue.

Communication with the EV charging box is carried out via two contacts, the control pilot contact (CP) and proximity pilot contact (PP). The EV charging box and vehicle communicate with one another through the CP contact the PP contact is passive. Both contacts refer to PE as 0 V. Normally, the CP conductor is white, the PP conductor red or orange, and the PE conductor is green-yellow.

The vehicle loads the CP contact with a resistance and thereby transmits the status A, B, C, D, or F to the EV charging box. The EV charging box uses the pulse width of a 1 kHz signal (PWM) to specify the maximum current with which the vehicle may charge to the EV charging box. During the negative pulse width, the voltage is minus 12 V. As long as no charge release is available, there is no PWM signal; instead, there is a DC voltage of 12 V in status A, 9 V in status B or 6 V in status C.

If the EV charging box does not detect the connected vehicle, the CP signal may be the cause.

Measure the voltage between CP (positive) and PE (negative) in DC mode. Use a multimeter and not a voltage tester to do so.

If there is no voltage between CP and PE, measure the voltage in the socket of the EV charging box (SOCKET variant) or on the connection terminals (PLUG variant).

NOTE: The 12 V is measurable only if the status LED on the EV charging box is illuminated green, meaning there is no error. With an AC HOME EV charging box, please ensure the EV charging box is mounted correctly on the mounting plate. If the subsurface is very rough (plaster), the EV charging box may seem to be flat against the wall, but the contacts may not be inserted fully. In this case, the seals will also not be correctly fitted, and there is a risk of humidity getting inside the EV charging box.

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