Charging from NEMA 6-20 using NEMA 5-20 Adapter

[Stasla]

Yeah I doubt that the 6-20p to 5-20R adapter is bad there are no electronics involved just copper to copper...

I haven't tried the adapter on any 5-20R outlets, because I have none in the house

The UMC light is green when breaker is on with my convoluted 6-20 setup, and it's not plugged into the car. As soon as I plug the car in the voltage on the charging screen is cycling between 1 and 0 briefly at 16 Amps but then the breaker trips and it never starts charging. After the breaker trips it appears that the Amperage setting in the car gets reset to 48a (so I was wrong about the car dialing it up while charging it appears)

The 14-50 charging was working fine at the store although they used their own UMC.

I don't have a 14-50R at the house unfortunately- need a service upgrade (only 100amp service on the main panel - old house) and a new line to get it which was estimated at $5000 by a friendly electrician, hence the 6-20 finagling I'm clearly.messing up on.

The weird thing is that the pool pump on the same circuit turns on fine without tripping the breaker. But the UMC/car combo trips it every time.

That's very strange. Someone just returned my similar 6-20 to 5-20 after using it on a trip and said it worked just fine. Have you ever used your UMC 5-20 adapter by itself in a 120V 20A outlet? I wonder if that is defective. Also has your car set the amps wrong when using a 14-50?

 

[TexasEV]

Pool pump on the same circuit? That may be your problem. You shouldn't have anything else on the circuit you are plugging the car into.

You can test your UMC and 5-20 adapter almost anywhere. Just about all commercial buildings and garages will have 5-20 outlets.

 

[Stasla]

Same circuit, but off/ power cut to the pool pump outlet via timer switch (Intermatic 240v timer)

I tried to plug in the car in the pool pump outlet also and the breaker still trips.

When the pool pump starts/runs on the same circuit/outlet - everything is fine.

Could it be a faulty breaker or a wiring issue?

One other thing I noticed is there is slight hum/buzz when the breaker is on, in case that gives you any clues.

Thanks again for sharing your thoughts and quick responses!

Pool pump on the same circuit? That may be your problem. You shouldn't have anything else on the circuit you are plugging the car into.

You can test your UMC and 5-20 adapter almost anywhere. Just about all commercial buildings and garages will have 5-20 outlets.

 

[TexasEV]

I think the problem is in your home and not the UMC or adapter, but you can test it as noted above. If the 5-20 works elsewhere, time to call an electrician.

 

[Stasla]

That's what I'm starting to think too.
Thanks!

I think the problem is in your home and not the UMC or adapter, but you can test it as noted above. If the 5-20 works elsewhere, time to call an electrician.

 

[Rocky_H]

It does sound like something is shorted in that outlet installation--the car bouncing around 1 and 0 V, as it realizes it can't get a real voltage.

 

[Stasla]

@Cosmacelf was kind enough to help me troubleshoot it last night and all signs point to the GFCI panel breaker being tripped by the UMC as part of initial charge cycle starts up routine. I'm planning to test this theory by replacing the GFCI breaker with a regular 20AMP 240v one and see if that holds. Will report back!

It does sound like something is shorted in that outlet installation--the car bouncing around 1 and 0 V, as it realizes it can't get a real voltage.

 

[linkster]

Stasla

Might you take look and see if your washing machine or microwave (both typically the sole receptacle on a branch circuit) outlets are plugged into a 5-20 outlet where you can test or deploy your Tesla UMC 5-20 adapter for ~5mph charge rate until you sort out your 6-20 wiring device issue?

 

[Stasla]

Thanks for the suggestion! Unfortunately I have no 5-20R outlets anywhere in the house. But I did test the voltage with the voltmeter at the slots on the back side of the Tesla 5-20P adapter (unplugged from UMC cable) and I'm getting 250v across hots and 125v or so from either hot to ground. This is with the EVSEADAPTERS.COM 6-20p to 5-20R adapter in place.

Seems that the GFCI breaker doesn't like the UMC handshake procedure and trips before the charging starts.

@Cosmacelf explained to me via PM that UMC sends a small dose of current to ground to test for proper grounding and the breaker doesn't seem to like that much, so it trips.

Anyhow that's the leading theory at the moment, will try to replace the breaker with a similarly rated non-GFCI version and test it again.

Will report back!

Stasla

Might you take look and see if your washing machine or microwave (both typically the sole receptacle on a branch circuit) outlets are plugged into a 5-20 outlet where you can test or deploy your Tesla UMC 5-20 adapter for ~5mph charge rate until you sort out your 6-20 wiring device issue?

 

[linkster]

Yup, my money is on Cos as he has been around here a long time. I am generally not a safety conscious person, but I would be very mindful of the elimination of an important safety device for your hot tub.

Good-Luck!

btw, CRAAZY gorgeous blue!

 

[Cosmacelf]

I think it was a pool pump. If the regular breaker works, then most likely a new GFCI breaker will also work. The existing GFCI breaker is probably just old and worn out and thus too sensitive.

 

[Stasla]

Yup, a pool pump. It's far enough from the pool that it will be highly unlikely to get splashed, let alone submersed. Plus the pool is only in use a 3 months out of the year - tops. East Coast represent

Picked up a 20A single pole GFCI breaker that says 120/240v on it. And a non-GFCI 20 double pole breaker at Home Depot today.

Will try both tomorrow and report back!

I think it was a pool pump. If the regular breaker works, then most likely a new GFCI breaker will also work. The existing GFCI breaker is probably just old and worn out and thus too sensitive.

 

[Cosmacelf]

A single pole breaker isn't going to give you 240V, not sure how that's going to work...

 

[Stasla]

Yeah, I thought so too, and just confirmed it with GE support (breaker manufacturer) the package said 120v/240v on it which is what threw me off. That one is going back to Home Depot

A single pole breaker isn't going to give you 240V, not sure how that's going to work...

 

[Stasla]

Update: replaced the breaker with non-GFCI and it's charging like a champ at 240v/16a filling up that 75kwh batt at 10m/hr!

Huge thanks to @Cosmacelf for all his guidance and advice!!! You rock, man!

Now I just gotta figure out whether this non GFCI setup is gonna be safe in the long run or whether I will need to try another GFCI breaker.

One thing I noticed is that the old GFCI breaker only had 2 hots going to it - no neutral, while it had its own neutral coiled wire connected to the neutral bus on the subpanel. Perhaps that's what was throwing the UMC off and tripping GFCI on the breaker? If that's the case, not sure if a replacement GFCI breaker won't behave the same way... ponderous, very ponderous...

Yeah, I thought so too, and just confirmed it with GE support (breaker manufacturer) the package said 120v/240v on it which is what threw me off. That one is going back to Home Depot

 

[TexasEV]

The UMC has GFCI built in. Maybe two them don't work together.

 

[Stasla]

Yup, not worried about protecting the car as the UMC has the GFCI built in, as you said.

I'm thinking of that Pool pump - that's the 240v line that is no longer GFCI protected.

The UMC has GFCI built in. Maybe two them don't work together.

 

[tga]

I wouldn't run the pool pump without a GFCI. If the UMC won't work with a GFCI breaker in the panel, you could have an electrician install a single breaker box between the 6-20 outlet and the pool pump with a GFCI breaker.

 

[Stasla]

Hmm. That's an interesting thought. Will look into this- thanks!

I wouldn't run the pool pump without a GFCI. If the UMC won't work with a GFCI breaker in the panel, you could have an electrician install a single breaker box between the 6-20 outlet and the pool pump with a GFCI breaker.

 

[Cosmacelf]

My pool pump doesn't have a GFCI. It is hard wired, not a plug, but no GFCI.

The problem most likely isn't the fact that it is a GFCI breaker, it is probably that the GFCI is just old. I suspect that a new GFCI breaker will work just fine with the Tesla.