HPWC no light after one week

[Kira]

Prefacing by saying I am not an electrician, so apologies in advance...

Our HPWC was installed one week ago by a family member and passed inspection by the city's chief electrical inspector. We have 200 amp service and I believe the HPWC was installed with #3 AWG wire and (I think) is on a 72 amp breaker. The internal switch inside the HPWC is set for 48 amp charging rate.

I've charged without any issues a few times this past week.

Last night I happened to wake up in the middle of the night and noticed on my Tesla app that the scheduled charge hadn't happened and there was a message saying something to the effect of "Check charger power". After unplugging the car, I looked at the HPWC - no light at all, no green or red. I then checked the breaker - it was actually still on. I turned the breaker off, then back on. Still no light on the HPWC. Tried the reset button - nothing.

Family member who installed it came to check and went through the same process as I did with flipping the breaker. He then used a little tool to see if there was power going to the HPWC and said that there is. So, it seems like the issue may be inside the HPWC.

Just thought I'd inquire whether anyone has experienced something like this? I had to rush to work, but will of course go through the trouble-shooting section of the manual this evening and contact Tesla, etc.

 

[Lloyd]

check the fuse in the HPWC and the connections inside. You likely have a 100 amp breaker. No such thing as a 72 amp breaker.

Also, try the reset on the side of the HPWC if you have not done that.

 

[Kira]

check the fuse in the HPWC and the connections inside. You likely have a 100 amp breaker. No such thing as a 72 amp breaker.

Thanks Lloyd, will try that this evening!

 

[eprosenx]

The only wiring things I could think of would be that the two hot wires are 240v leg to leg, and that you see 120v from each to ground. Make sure all connections in all points of the path starting at the panel (especially the ground if you did not already test that) are tight.

I don’t see how the hpwc would fail to get a green light as long as you see 240v leg to leg and 120v from each leg to ground. That is all it can really test for. Loose (but touching) connections might not manifest themselves until under load while charging, but you are just talking about the HPWC not booting up...

Note that it does have a lockout timer of some amount after a “power outage” to keep all the cats from slamming the grid at once after an outage. But it is not that long I don’t think. 3 minutes? Check the manual.

Very likely could be a defective unit. Call tech support.

 

[Kira]

The only wiring things I could think of would be that the two hot wires are 240v leg to leg, and that you see 120v from each to ground. Make sure all connections in all points of the path starting at the panel (especially the ground if you did not already test that) are tight.

I don’t see how the hpwc would fail to get a green light as long as you see 240v leg to leg and 120v from each leg to ground. That is all it can really test for. Loose (but touching) connections might not manifest themselves until under load while charging, but you are just talking about the HPWC not booting up...

Note that it does have a lockout timer of some amount after a “power outage” to keep all the cats from slamming the grid at once after an outage. But it is not that long I don’t think. 3 minutes? Check the manual.

Very likely could be a defective unit. Call tech support.

Thank you very much - I definitely will check the manual and call tech support. Hopefully we won't need a new one - it was rather challenging to wrestle the thick wire into place during the install from what I heard.

 

[Kira]

Update - crisis averted! It was indeed a loose connection to one or both of the hot wires. Charging at full speed again, thank goodness.

I love this forum - thanks again @Lloyd and @eprosenx

 

[eprosenx]

Update - crisis averted! It was indeed a loose connection to one or both of the hot wires. Charging at full speed again, thank goodness.

I love this forum - thanks again @Lloyd and @eprosenx

Glad to hear it!

Out of curiosity, which end or location was the loose connection?

Loose connections and electric vehicle chargers are nothing to mess around with. Large continuous draw devices that operate while folks are typically asleep are a recipe for house fires at bad times of day. Granted modern electric vehicles have some safe guards that typical electrical devices do not, but we never want to take this for granted!

 

[Kira]

Glad to hear it!

Out of curiosity, which end or location was the loose connection?

Loose connections and electric vehicle chargers are nothing to mess around with. Large continuous draw devices that operate while folks are typically asleep are a recipe for house fires at bad times of day. Granted modern electric vehicles have some safe guards that typical electrical devices do not, but we never want to take this for granted!

I think they both may have been a little loose but the red one seemed more loose. I’m sure I’m not explaining this correctly at all, but they were loose behind the little green part (terminal block?). Thinking that a bit more insulation should have been stripped in order to get them shoved up properly.

I’m surprised that the electrical inspector didn’t check all this when he came....

 

[eprosenx]

I think they both may have been a little loose but the red one seemed more loose. I’m sure I’m not explaining this correctly at all, but they were loose behind the little green part (terminal block?). Thinking that a bit more insulation should have been stripped in order to get them shoved up properly.

I’m surprised that the electrical inspector didn’t check all this when he came....

Do not trust electrical inspectors to make sure you are safe. I have found them woefully underprepared to inspect EVSE installations. Mine did not even look at a single wire I ran. Just my pipe bending work (externally).

Note that they can’t check every connection (time wise) and they don’t generally remove wires from terminals to check insulation strip depth.

They really are only able to catch the egregious stuff...

If you think there is any chance that insulation is stuck under the screw terminal I would have it checked out. Making bad contact at these high amperages would be dangerous.

Is it safe to assume that you used copper wire? What size breaker did you use?

 

[Kira]

Do not trust electrical inspectors to make sure you are safe. I have found them woefully underprepared to inspect EVSE installations. Mine did not even look at a single wire I ran. Just my pipe bending work (externally).

Note that they can’t check every connection (time wise) and they don’t generally remove wires from terminals to check insulation strip depth.

They really are only able to catch the egregious stuff...

If you think there is any chance that insulation is stuck under the screw terminal I would have it checked out. Making bad contact at these high amperages would be dangerous.

Is it safe to assume that you used copper wire? What size breaker did you use?

Definitely, the wire used is #3 (AWG?) and it is copper. The breaker is 60 amp, I thought he may have bought a 72 but I just went to double-check and it’s 60.

Here are some photos, though just of the panel as the HPWC is closed up for now. I did look carefully while it was opened and did not see any insulation bits/edges going up into the screw terminal area.





Very grateful for your practical & kind help!

 

[eprosenx]

Good!

Wow, that is a unique panel! Two 100a feeds out of it plus the Tesla charger. What do those 100a’s go to? Subpanels?

P.S. Did you set the rotary switch correctly for the 60a breaker? This is the same amperage breaker I have for my M3 since that will charge it at the max rate. With awg 3 conductors you will be all set to later up the breaker!

 

[Kira]

Good!

Wow, that is a unique panel! Two 100a feeds out of it plus the Tesla charger. What do those 100a’s go to? Subpanels?

P.S. Did you set the rotary switch correctly for the 60a breaker? This is the same amperage breaker I have for my M3 since that will charge it at the max rate. With awg 3 conductors you will be all set to later up the breaker!

Yes, exactly - they go to sub panels. We built an addition out back. We have just the one meter, but it’s more convenient to have things separated into two panels.

We set the rotary switch for 48amps (I think the number 9 on the little dial) - I didn’t realize we could set it for higher? It charges around 71km/hr right now on that setting.

 

[eprosenx]

Yes, exactly - they go to sub panels. We built an addition out back. We have just the one meter, but it’s more convenient to have things separated into two panels.

We set the rotary switch for 48amps (I think the number 9 on the little dial) - I didn’t realize we could set it for higher? It charges around 71km/hr right now on that setting.

#3 awg copper in NM cable is good to 85 amps (100 amps if in conduit which allows the rating to go to 75c). So you could upsize your breaker to 80 amps (do they make that size?) and set the rotary dial up that high. Actually, I would need to refresh my memory, but you might be allowed to go to a 90 amp breaker (by the next size up rule) but still only set the rotary dial the the highest setting that does not exceed 85 amps when multiplied by the continuous load 1.25 multiplier.

But this would not make any difference to a model three since its max charge rate is 48 amps so the largest breaker you need is 60 amps.

If you did want to upsize, you would need to do a load calculation anyway to ensure your 200a service was not oversubscribed (assuming it is a 200a service).

 

[Rocky_H]

The Model 3 you have cannot take any higher than 48A anyway, so the 60A breaker is correct to leave the required amount of overhead. Whoever did the install set all that part up right. Although...tighter wire connection would have been better the first time.

 

[nrechtman]

That breaker doesn’t look like it’s set properly with the cover, there appears to be a gap, or the breaker is seated at an angle, I would shut your main off at the meter and make sure the breaker is set and the panel cover fits properly

 

[Kira]

The Model 3 you have cannot take any higher than 48A anyway, so the 60A breaker is correct to leave the required amount of overhead. Whoever did the install set all that part up right. Although...tighter wire connection would have been better the first time.

Yes, we did get some tips from an electrician before buying the breaker and he was very clear that we should get at least a 60A.

That breaker doesn’t look like it’s set properly with the cover, there appears to be a gap, or the breaker is seated at an angle, I would shut your main off at the meter and make sure the breaker is set and the panel cover fits properly

Thank you, we'll do that! Some of it may also be my lousy camera skills - was trying to hold the panel cover open with one hand and the phone upside-down.

 

[Seamus]

Hi Kira,
I am curious how many KM?H you the with the charger? I have not ordered one yet. I had my electrician install a 240 plug and I am getting 46 KM/H.

 

[Kira]

Hi Kira,
I am curious how many KM?H you the with the charger? I have not ordered one yet. I had my electrician install a 240 plug and I am getting 46 KM/H.

The most I’ve personally seen is 71 km/hr but perhaps it goes a wee bit higher than that? I schedule the charging to happen in the middle of the night. Aside from this little loose connection hiccup, which was our fault, the HPWC is really great - though we didn’t have a 240 plug!

 

[Rocky_H]

I had my electrician install a 240 plug and I am getting 46 KM/H.

the HPWC is really great - though we didn’t have a 240 plug!

This lack of terminology is starting to get to me. People are referring to "240 plug" as if that's just one thing. There are 120 volt circuits and 240 volt circuits in your house, and they can be on many different amp levels, and how many amps the circuit is plays a major role in determining your charging speed. It could be a 240V 15A circuit, and that will be way slower than a 240V 80A circuit. So if you want to ask any questions about charging speed, you really need to mention what volts and amps your circuit is.

 

[Kira]

This lack of terminology is starting to get to me. People are referring to "240 plug" as if that's just one thing. There are 120 volt circuits and 240 volt circuits in your house, and they can be on many different amp levels, and how many amps the circuit is plays a major role in determining your charging speed. It could be a 240V 15A circuit, and that will be way slower than a 240V 80A circuit. So if you want to ask any questions about charging speed, you really need to mention what volts and amps your circuit is.

Sorry Thanks for the opportunity to learn!