Blog - Installation diagrams

DC Wire Color Coding Standards

DC Wire Color Coding Standards

08.Feb 2021
| Blog - Installation diagrams

The table shows the color coding for AC wires in the installations.

DC Plus Pole (+) – Red
DC Minus Pole (-) non-grounded – Blue  (#1)
DC Minus Pole (-) grounded – Black  (#2)
Protective Earth (PE) or Ground (GND) – Yellow/Green


#1 For majority DC systems the battery poles and all DC wires must be galvanically separated from the body of the device or from the outer case of the equipment. This is called “the floating potential” – there is no electrical potential between the DC poles and the outer objects, casing and also the grounding.

#2 In some systems, the DC minus (-) pole is grounded. In this case, it is recommend to use the black color to indicate that the minus pole is galvanically connected to the GND. This is often the case of the 12V car battery. The car battery is connected to the body of the car. This many able be the case in some DC energy storage systems, where there is an auxiliary battery to power (or backup) the control circuitry. In this case the battery minus will be marked in black, indicating the connection to GND.

Link for reference

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