Help!! NEMA 10-30 Issues

[Big Earl]

Since it is a 10-30, the receptacle is at least 25 years old. It could be bad, heating up, the temp sensor in the UMC plug is detecting the problem, and dropping the charge current accordingly.

When this happens, I’d suggest stopping the charge by unplugging the UMC from the car. Then unplug it from the 10-30 and feel the blades on the plug. If they are hot you’ll know there is a problem with the receptacle. Could be something as simple as tightening the screws that clamp the wires to the receptacle.

This ^

 

[srs5694]

Another option if the wiring is undersized would be to downgrade the outlet to a 6-20. No rewiring and they'd still charge at triple the effective rate of a 5-15.

That's true, although I'd want to be sure the wiring is capable of handling 20A (peak). If it should be able to handle 30A but is heating up, it's conceivable that even 20A would be too much. OTOH, maybe the wiring was simply under-spec for a 30A circuit but it worked OK with whatever dryer was originally used with the outlet. It's still unclear why @GlassJAw88 thinks the in-the-wall wiring is the cause of the problem.

What’s the process of downgrading it?

If you're not familiar with electrical work, it's probably best that you hire an electrician. The job shouldn't be very hard; it involves a few dollars in parts and a few minutes of labor. It'd be just like replacing a light switch or 120v wall outlet -- turn off the breaker, take apart the wall outlet, put it back together with the new receptacle, turn on the breaker, and use it. (Replacing the breaker to reflect the new amperage of the outlet is also desirable. This would add a few more dollars and a few more minutes to the job.) The trouble is that if you've never done electrical work before, you could easily electrocute yourself or put it together in an unsafe way that could cause a fire. Also, if your existing wiring is under-sized or worn to the point that it's causing problems, it's imperative that it be checked to ensure that it's up to the task, even at a reduced amperage.

 

[Eno Deb]

I currently got my model 3. I have a dryer outlet that I was going to use to charge the car. However after purchasing the adapter from Tesla it didn’t hold the charge for very long. It'll start to charge at 24 for a few minutes than go down to around 12 or so.
At that time the UMC would have the “T” flashing red.
I also get a message saying something about being too hot.

Could be a problem in the UMC itself or in the wall outlet (loose and/or corroded contacts). The UMC has multiple temperature sensors. The blink pattern of the red LED should tell you which one triggered the current reduction (for example, if you see 4 flashes, it detected high temperature in the wall outlet). See pages 11/12 in the UMC manual:

https://www.tesla.com/sites/default...bile_connector_owners_manual_32_amp_en_US.pdf

 

[davewill]

What’s the process of downgrading it?

For starters, the wire size (assuming copper) should be minimum 10AWG for 30a, 12AWG for 20a, and 14AWG for 15a.

The process of replacing the 10-30 with a 6-20 or 6-15 is simple enough. The 10-30 should be the only outlet on the circuit and you will not be able to plug a dryer into that outlet anymore.

NOTE: I'm not a professional, just a guy on the Internet. I'm not telling you to do this, and I'm not responsible if you have problems. It's your responsibility to be sure everything is done right. If you're not confident, let a professional do the work.

To do the conversion:
1. Turn off the breaker to the outlet and the main breaker to the panel.
2. Replace the breaker for the outlet with a 20a (for 6-20) or 15a (for 6-15) breaker.
3. Detach the wiring from the 10-30. The two slots are the hots (wire is usually red and/or black), and the L shaped hole is neutral (usually white). You may have a separate ground wire in the box as well, it would usually be either green or bare.
4. If there is no separate ground wire run, then you have to repurpose the neutral wire as a ground. (See extra steps below)
5. Attach the two hot wires to the two slot connections on the 6-20/15 (doesn't matter which goes to which slot).
6. Attach the ground wire to the round ground connection on the 6-20/15. Also connect it to the box if it's metal.
7. If you have a neutral wire left over, cap it off at the outlet end.
8. Double check every connection.
9. Turn on the main breaker, then the breaker for the circuit.
10. Double check voltages at the outlet with multimeter. You should have approx 240v between the two slots, and 120v between each slot and the ground pin.

If there's no separate ground wire in the box, you have to repurpose the existing neutral as a ground. The Tesla 10-30 adapter is doing this already internally. To repurpose the neutral wire:

1. Label the existing white neutral wire with green tape at both ends.
2. If the 10-30 is connected to a subpanel, move the new ground wire from the neutral bar to the ground bar.

BTW, If the 10-30 is on a subpanel, that could also be the source of problems. The Tesla 10-30 adapter uses the neutral as if it were a ground. That assumption only holds up if the 10-30 is wired directly from the main panel and it is the only outlet on the circuit. Otherwise, the neutral will not always be at ground potential, and the EVSE may detect that as a ground problem.

 

[darth_vad3r]

I only spent about two hours one evening using a level 2 charger. During that time my wife and I went to dinner and the charge was free.

Northern Viginia has level 2 chargers in a number of locations and 10 Tesla Super Chargers were installed about 4 miles a way at the Village at Leesburg so there are plenty of options here.

Good luck with your charging. If your commute is less than mine you, let's say 40 miles you may be able to get away with charging from a regular wall outlet on a daily basis.

In OP’s other thread commute was stated as 15 miles round trip — he should be laughing with only 120V overnight