Nema 14-50 won’t charge 120 will

[Darthbenji]

At my parent’s for the first time since getting the model 3. My dad installed a 14-50 for me and I’m trying the adapter that came with it. The in car screen just says ‘ready to charge’. We’ve confirmed power to the outlet, power to the adapter piece and to the transformer portion. Beyond that there’s no power the run of the cable going into the car. However, if we swap adapters and use the standard 120 and plug it it’ll charge at 8km/h. The current tester lights up the entire run.

Any ideas? Defective 14-50 adapter?

 

[tjkessler]

Maybe issues with the ground?

 

[FourOhFour]

How are you confirming power to the outlet? If you're using a multimeter, are you getting 240v across the two hots? A miswired 14-50 could have 120v between hot and neutral but 0v across the hots if the two hots are wired together. Or 120v across the hots if a hot and neutral were swapped.

If the outlet's good, I'd contact tesla... my guess is either the mobile connector or the adapter is bad. Probably the mobile connector, there isn't much to the adapters.

You'll never see any voltage at the car connector unless it's actually connected... the car needs to signal it is ready to charge before the cord is energized.

 

[eprosenx]

Yes, to second FourOhFour:

Check for 240v from phase to phase, 120v from each phase to neutral (two tests), plus 120v from each phase to ground (two tests).

Then neutral to ground should be 0v.

Really, the UMC does not care at all about the neutral and it does not use it. But good to test it none the less.

My guess is something is wired wrong either at the outlet end or in the breaker panel. There are some breakers that if you install them in the wrong spot, both "hot" wires end up on the same phase leg and hence end up with 0v potential between them.

Also, feel free to post pictures of the outlet wiring and the breaker panel if you want an extra set of eyes.

 

[Darthbenji]

So the mobile connector works when using the 120 adapter for the common household plug. It charges. When it’s plugged into the 14-50 there’s nothing. Other than that multimeter lighting up at the outlet, along the adaptor and to the transformer. Beyond that, the cable portion, there’s nothing.

Does it matter if the 14-50 outlet is installed on a 30 amp breaker?

 

[eprosenx]

So the mobile connector works when using the 120 adapter for the common household plug. It charges. When it’s plugged into the 14-50 there’s nothing. Other than that multimeter lighting up at the outlet, along the adaptor and to the transformer. Beyond that, the cable portion, there’s nothing.

Does it matter if the 14-50 outlet is installed on a 30 amp breaker?

The UMC has a "contactor" (relay) inside of it and it won't turn on power to the car until it establishes communication with the car. So don't expect it to be "hot" with a multimeter at the end of the cable ever.

A multimeter does not "just light up". It should give you voltage readings. I am wondering if you do not have voltage (potential) between the two hot wires (left and right holes), or perhaps the ground is not properly connected and so the UMC is failing its grounding test and so it won't operate.

Do any lights light up when you plug the UMC into the 14-50?

 

[eprosenx]

Does it matter if the 14-50 outlet is installed on a 30 amp breaker?

No. It will work just fine on a 30 amp breaker, just set your max charge voltage to 24a or less or else you could blow the breaker (or possibly start a fire if the wiring is not of sufficient ampacity). This would probably not be a recommended setup (or actually, probably not code compliant either since your intended load is 32a per the nameplate and requires a 40 amp breaker).

I do not believe that manually setting the car down to 24a counts from a code standpoint (but I would not have any hesitation doing it for a temporary charging setup personally).

 

[Darthbenji]

No lights. Just when it’s plugged into a 120.

The voltage tester we have just lights up red and flashes when it detects current.

 

[roblab]

So the mobile connector works when using the 120 adapter for the common household plug. It charges. When it’s plugged into the 14-50 there’s nothing. Other than that multimeter lighting up at the outlet, along the adaptor and to the transformer. Beyond that, the cable portion, there’s nothing.

Does it matter if the 14-50 outlet is installed on a 30 amp breaker?

It would matter to me. Someone might easily change the charge amps of the car, or it could do it by itself by over the air downloads. Nothing would happen but a tripped breaker, most likely.

It would be easy enough to find another 14-50 outlet, I would imagine, and test it again. If you take it to Tesla for an exchange, the first thing they do is take it back into the shop and plug it in to a known outlet.

 

[Darthbenji]

No. It will work just fine on a 30 amp breaker, just set your max charge voltage to 24a or less or else you could blow the breaker (or possibly start a fire if the wiring is not of sufficient ampacity). This would probably not be a recommended setup (or actually, probably not code compliant either since your intended load is 32a per the nameplate and requires a 40 amp breaker).

I do not believe that manually setting the car down to 24a counts from a code standpoint (but I would not have any hesitation doing it for a temporary charging setup personally).

Gonna try that now

 

[eprosenx]

No lights. Just when it’s plugged into a 120.

The voltage tester we have just lights up red and flashes when it detects current.

Which holes on the plug cause your non-contact voltage detector to light up? Also, please post pictures of the breaker panel with the cover removed if you can safely do this.

 

[eprosenx]

Gonna try that now

Setting it to 24a won't cause it to work if you are not getting any lights on the UMC when plugged into the 14-50. The 24a only comes into play to avoid blowing the breaker once it does start charging. You have something more fundamental going on.

Odds are this is just a wire mis-wired.

I am wondering if perhaps both "hot" pins on the 14-50 plug are wired to the same "phase leg" which means that while they are both "hot" with power, they don't have any voltage potential between them.

 

[Darthbenji]

Gonna post pictures tomorrow once we go out and take it apart.

Dialing down to 24 and then trying did nothing. The Tesla logo lights up on the UMC when plugged into the regular wall outlet but nothing when plugged into the 14-50

 

[TexasEV]

Separate issue, but if it’s on a 30A breaker you should install a 14-30 outlet and use that adapter not 14-50. Here are the relevant installation instructions from Tesla:
14-50 outlet- Tesla
14-30 outlet- Tesla

 

[Darthbenji]

He installed the 14-50 after looking at my adapter kit. He just used a 30 amp breaker

 

[tjkessler]

You could get a Tesla 14-30 adapter and install a 14-30 outlet. That's a safer option with 30AMP breaker. eprosenx's debug advice
is quite good. A simple tester light won't due, you really need a multimeter to make sure the voltages
are right. It's probably not a simple ground fault as the UMC would light up with an error.

 

[Darthbenji]

The breaker was in the wrong position in the panel. Working now.

 

[eprosenx]

The breaker was in the wrong position in the panel. Working now.

Great! Glad it worked out for you!

Question: Does that mean you have a "Federal Pacific" Stab-Lok panel? Those are the only ones I know of that can have the problem you describe.

FYI, those panels are generally considered to be a fire hazard. There is lots of information online about these issues.

 

[Rocky_H]

He installed the 14-50 after looking at my adapter kit. He just used a 30 amp breaker

That is a blatant violation of electric code and needs to not be that way. A 30A breaker must have a 30A outlet on it. You're only allowed to mismatch things like that if it's something like a 40A circuit because there doesn't happen to be a 40A outlet type. So if this only has wire that supports 30A current, you need to switch that and put a 14-30 outlet on it, not a 14-50 outlet.

 

[Darthbenji]

Actually it turns out it’s 40 amp breaker. It charged at 32 amps.

When I’m back later I’ll check the type of panel.