PE connection of controller conforming to standards (double or > 10 mm²) - background information on EN 61800-5-1

Question:
According to the connection examples in the Mounting Instructions, the controllers require a double PE connection. What is the reason for this?

Answer:
During controller operation, the discharge current to earth (PE) usually is > 3.5 mA AC or > 10 mA DC. In these cases, EN 61800-5-1 requires the following measures to ensure the protection of persons when the PE conductor fails:

a) Connection via a plug connector for industrial applications according to IEC 60309 and a minimum PE conductor cross-section of 2.5 mm² as part of a multi-core supply cable. An appropriate strain relief must be provided.

or

b) Fixed connection and
- a PE conductor cross-section of at least 10 mm² or
- connection of an additional connection terminal for a second PE conductor with the same cross-section as the original PE conductor.

For the fixed installation, the additional PE conductor can be connected on the mains side or on the motor side of the controller. It is important that the double connection will not be carried out under the same connection terminal. Some inverters have a double PE connection on the mains side.

Extract from 8400 BaseLine Mounting Instructions (double PE connection on the mains side):