Last edit: 10/05/2023
Functional grounding is not used for protection from indirect contacts, but for:
- Shielding of signal cables
- The "0" or "common" of control part and electronics
- All devices required to be grounded for ElectroMagnetic Compatibility (EMC) issues
Therefore shall IEC 60445 be applied to machineries? Is it necessary to connect a pink functional grounding conductor?
The answer to this question can be found at the beginning of IEC 60445, within Section 1 "Scope":
This basic safety publication is primarily intended for use by technical committees in the preparation of standards in accordance with the principles laid down in IEC Guide 104 and ISO/IEC Guide 51.
It is not intended for use by manufacturers or certification bodies. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. The requirements of this basic safety publication will not apply unless specifically referred to or included in the relevant publications.
It is explicitly stated that this Standard is a Basic Safety Standard, of Category A, and is addressed to the members of the technical committee writing it and not to an end user or manufacturer. Following what is written there is no reason to apply IEC 60445 and then install a pink functional grounding cable inside an industrial control panel.
WHICH STANDARD SHALL BE APPLIED? PINK OR GREEN-AND-YELLOW COLOR?
"Category B" Standards, Group Safety Standard, are addressed both to those who write product standards and to manufacturers or test laboratories.
"Category C" Standards, Product Safety Standard, are addressed to manufacturers; for example IEC 60204-1 is addressed to manufacturers of nidustrial control panels.
At this point a manufacturer knows that he shall refer to IEC 60204-1 Category C Standard and not to IEC 60445 Category A Standard. Moreover, IEC 60204-1 does not specify the color of functional grounding conductors. As a result, the functional grounding conductor can be GREEN-AND-YELLOW (reasonable choice for convenience and habit) or any other color, but not necessarily pink.
Another similar debate concerns the colors of three phase conductors inside an industrial control panel. IEC 60445 recommends the colors of the three phases (their conductors are indicated as Line 1, Line 2 and Line 3 and the terminals as U, V and W): they are respectively black, brown and gray. But in IEC 60204-1 is written:
Where colour-coding is used for identification of conductors, it is recommended that they be colour-coded as follows:
– BLACK: AC and DC power circuits.
Therefore, referring to IEC 60204-1, as it should be, and not IEC 60445, BLACK should be used as color of the conductors of all three phases inside an industrial control panel.