Porsche PMCC Charger Critical Ground Fault???

[FrozenRobert]

Apologies if this has been answered previously. But I'm at my wit's end. I was up until 01:30 A.M. last night trying to solve this, was on the phone with the dealer all day, and even had my electrician come back to double-check his work.

There's absolutely nothing wrong with the install. I watched my guy like a hawk, he knows his stuff and I agreed that it is NOT my house.

PROBLEM #1: Beautiful PMCC Porsche official charger powers up, then entire screen goes RED and shows vague error of "CHARGE NOT POSSIBLE" and no explanation. Re-boots and hard-resets make no difference.

SIDE ISSUE: PMCC does NOT recognize my Taycan 4S. When I plug in the J1772, nothing happens. My car sends an error message to the console saying "CHARGE NOT POSSIBLE". Extremely vague and puzzling.

Dealer has no idea WTF is wrong. Electrician is 100% competent and he came BACK to my house on the weekend to check his work (the install was yesterday) -- it's NOT my electrician, or my house. The load is calculated correctly and there should be NOTHING from keeping the charger from operating correctly. Software is latest update. WiFi and hotspots 100% good.

GROUND FAULT is disabling entire unit. I'm very disappointed. For this amount of $$$ I do not like this hassle. Especially when the dealer has no advice apart from sending me YouTube links.

Has ANYONE encountered this before? I'm having great difficulty getting any answers. Thanks in advance.

Sponsored

 

[Jhenson29]

https://www.taycanforum.com/forum/threads/charging-is-not-possible-grounding-device-error.1868/

 

[FrozenRobert]

https://www.taycanforum.com/forum/threads/charging-is-not-possible-grounding-device-error.1868/

Thanks! Appreciate it. Going to dealer ASAP.

 

[chrisk]

Do you have a grounding rod for you electrical panel or do you depend only on the network's grounding? If not then ask your electrican to install one (and question how competent they are).
If you do have grounding rod(s) then ask your dealer to loan you another PMCC to try.

 

[Jhenson29]

Thanks! Appreciate it. Going to dealer ASAP.

It’s worth noting that two of the posts in that thread did say there were wiring issues in the house.

https://www.taycanforum.com/forum/t...ssible-grounding-device-error.1868/post-27076

https://www.taycanforum.com/forum/t...ssible-grounding-device-error.1868/post-37837

 

[FrozenRobert]

Thanks to you both for your responses. Now I understand more clearly, re: the PMCC being (overly?) sensitive to incoming current and minor load variances / ground issues.

I'll have my electrician come back early next week and triple-check everything. My cousin (also an electrical engineer) really doubts it's my house. I have GFC plugs in baths etc., and I've never had any ground issues. This house is only 1.5 years old, new build, so I'm puzzled.

Once again, thank you for your help with this. I was surprised at how dumb-founded the dealer was. They were pleasant but really quite clueless. This forum is way more valuable.

 

[NC_Taycan]

I have experienced this issue once in 14 months - while charging at the paddock at a track (with a NEMA 14-50 extension cord). Reducing the charge current from 40A to 32A worked around the problem, but that isn't always going to work, and if you think about it, it shouldn't work.

If you consider the wiring in the plug, the only possible tests that the PMCC can do on the ground is to a) measure the potential (voltage) of each hot (120V) leg relative to ground, and b) measure the rate at which some accumulated charge can be dumped into ground. If the current isn't as expected given the (presumably fixed) amount of charge to dump, the PMCC assumes the ground connection is faulty (not actually connected at all, or higher than expected resistance to true earth ground). If it is testing the potential of the hot legs and triggering a fault if the legs have too big of an imbalance, it's possible that fault threshold is too low. It may also be looking for a drift in the imbalance (charge accumulating on the ground circuit because it is not properly connected to true earth ground).

It's possible that some other device might be briefly causing a sufficiently large imbalance or injecting charge into the ground circuit (e.g. at start-up or shut-down of a big-ass motor) and the PMCC is detecting this.

 

[Jhenson29]

Thanks to you both for your responses. Now I understand more clearly, re: the PMCC being (overly?) sensitive to incoming current and minor load variances / ground issues.

I'll have my electrician come back early next week and triple-check everything. My cousin (also an electrical engineer) really doubts it's my house. I have GFC plugs in baths etc., and I've never had any ground issues. This house is only 1.5 years old, new build, so I'm puzzled.

Once again, thank you for your help with this. I was surprised at how dumb-founded the dealer was. They were pleasant but really quite clueless. This forum is way more valuable.

If the electrician doesn’t find anything, it would be great if you had another receptacle, preferably at another location, you could try. Any friends with EVs or anyone on the forum in your area?

Then, you can also try a different PMCC from the dealer at your receptacle. I would hope they would loan you one to test.

Good luck!

 

[Kingske]

Thanks to you both for your responses. Now I understand more clearly, re: the PMCC being (overly?) sensitive to incoming current and minor load variances / ground issues.

I'll have my electrician come back early next week and triple-check everything. My cousin (also an electrical engineer) really doubts it's my house. I have GFC plugs in baths etc., and I've never had any ground issues. This house is only 1.5 years old, new build, so I'm puzzled.

Once again, thank you for your help with this. I was surprised at how dumb-founded the dealer was. They were pleasant but really quite clueless. This forum is way more valuable.

Please keep us updated on the outcome. As I reported earlier on this forum, the wiring and grounding needs to be in good shape (mine was not initially), but the PMCC is probably more sensitive to grounding imperfections than most chargers or appliances.

 

[FrozenRobert]

Update: Both Porsche Canada & my local certified electrician STILL totally stumped. No solution apart from (a) returning PMCC, or (b) dissecting home wiring. Getting frustrated.

Today, I borrowed an old cliché from the internet: unplug it from the wall, wait 1 minute, then plug it back in. Wait for the shiny lights to come on.

I turned off ALL high-load appliances in my house physically by either turning off the breakers at the panel, or actually removing the 240V breaker (i.e. in external A/C panel).

Then I turned off the 100-120 A main municipal breaker incoming to my basement. Waited about a minute. House was very quiet.

ka-CHUNK, turned everything back on. Went to my garage and plugged the PMCC back into the wall.

Called all relevant parties back. Relayed success (miracle).

I was able to adjust the current to the stated amperage suggested by my electrician on the PMCC menu, and everything is working 100%.

Why this should work -- my electrician is absolutely frazzled. He is coming over tomorrow to do a 3rd full house check (he was here both Fri. & Sat.) ... I'm just happy it works.

My middle-aged intuition (and info gleaned from forums) is that the PMCC is just very sensitive to load variances & domestic capacity. A 100% hard-reset seemed to clear it up.

Hope this helps someone in the future.

Sponsored