openinverter forum

On the weekend I build this Coolant pipes for my eBoxster. They are running parallel to shielded HV fast charge cables . They are clipped in into 3d printers holders and clamped to rubber tubes at the ends .

Do they need to be grounded ? If yes how is it done oem style ?

If the cables are shielded, they should not induce voltage on the pipes. And if they did, you would not want that stray voltage going to ground, because that will generate EMI on your 12v circuits which are grounded.

You can leave them ungrounded, or even better just electrically tie the ends to make a complete circuit to prevent capacitive charge buildup.

The coolant should be non conductive. Connecting them to the chassis should help prevent galvanic corrosion and also grounds them as a safer short path.

Unless there's a good reason not to, I think they should be grounded.

I know this is not completely sound logic, but I plan to ground mine for the reasons above. Thats what they do on every single aircraft I have worked on.

Just had a look with multimeter to my OEM car. Did not find metallic coolant lines, but found a lot of aluminium pipes for the refrigerant (heatpump for cooling and heating). Some are on ground, because just mounted to other grounded parts. A lot of these pipes do not have ground connection. Conclusion: No explicit grounding found.

If the OEM lines are aluminum they are likely anodized and will likely not show conductivity.

When there's dissimilar metals and or a current differential with a means of conducting between them you have a crude battery and the potential for galvanic corrosion. The OEMs make sure their coolant is non conductive and recommend changing it, sometimes very often to help prevent this possibility.

I really only see up sides on grounding the lines vs the effort to do it as the only con I can think of. This way if there are current going through the coolant it can be caught by the isolation monitor if equipped vs not knowing andv the potential of having live voltages on them.