Just had a Tesla charger installed. Charges are going at 12 amp at 246 volt?

[Niroc]

SR + (240 range). 12 amps with 246 volts according to M 3 display. That doesn’t seem quite right. Did the electrician get the wrong wiring or wrong circuit breaker? I think he put in a breaker at 40 max amps. These numbers sound like a Nema connector versus a Tesla wall connector?

It is charging sitting at 125 miles with estimation of 6 hours 50 minutes to go.

 

[MrMassTransit]

What is the car set to charge at? Does it allow you to increase the rate of charge up to 32 amps?

 

[ckoval7]

There is a rotary switch inside the wall connector to select the correct amperage. It's possible that was not set correctly. The switch is mentioned in the wall charger manual.

 

[ZOMGVTEK]

There’s a little dial inside the unit that tells it what size breaker it’s on. It has no way of knowing otherwise. It’s probanly at its default setting and needs to be turned up. You need to take the cover off and there’s a sticker inside to show you what to set it to. The cover can be tricky to get off, but otherwise it’s not difficult.

 

[linkster]

So very few electromagicians install the entire circuit correctly as they often miss the 125% continuous rule, don’t pull the proper wire/cable gauge, jam an incorrect (some are interchangeable) manufactures 2-pole breaker onto the buss bar because that is all that is in the storage bin inside their truck, and almost never RTFM to properly set the rotory/dip switches.

Good-luck.

 

[Niroc]

Ah so. I will check the wall connector switch. Thanks to all

 

[eprosenx]

Ah so. I will check the wall connector switch. Thanks to all

Yeah, fixing this is not hard.

But you need to know what the proper value to set it to is based on the wire size and breaker.

Presumably it is safe to set it to the breaker size (but the car will only charge at 80% of that due to continuous load requirements), but if the electrician messed up the setting on the Wall Connector then they may have made other mistakes. Might just be worth a call to them to confirm (also you could ask them to come and fix the whole thing since they are the ones that made the mistake).

 

[ZOMGVTEK]

It's exceptionally uncommon for a hardwired appliance to have a way to set its power. Most everything is fixed, or might have different load taps, but just about never a little knob to electronically set the power. Although in this case the wall connector is a fancy extension cord, and the actual load is the charger in the car. So I could see why most electricians won't understand it or even know it needs to be set. I'd say its very likely the breaker is sized to the wire. Although its not uncommon for a different but compatible breaker to be used since they had it in the truck. As long as its listed for the application its legal, the brands don't need to match.

Just check the breaker size, and set the knob inside the wall connector to 80% of it. So if you have a 60A breaker you need to set the knob to 48A.

 

[eprosenx]

Here is the chart for reference:

It lists both the breaker size and the max charge rate of the car at that setting.

 

[mswlogo]

Yeah, fixing this is not hard.

But you need to know what the proper value to set it to is based on the wire size and breaker.

Presumably it is safe to set it to the breaker size (but the car will only charge at 80% of that due to continuous load requirements), but if the electrician messed up the setting on the Wall Connector then they may have made other mistakes. Might just be worth a call to them to confirm (also you could ask them to come and fix the whole thing since they are the ones that made the mistake).

The "dial" is in "80%" units. So just to not confuse the OP, you don't set the dial to the Breaker Size. You set it to 80% of the Breaker size (most of the time). Some breakers can be "rounded up" by 5 Amps. So the dial is set to 80% of the Minimum of the Breaker Size or Wire Capacity.

As @linkster pointed out, if they got the dial wrong what else did they mess up.

 

[mswlogo]

Here is the chart for reference:

It lists both the breaker size and the max charge rate of the car at that setting.

View attachment 415061

Glad you posted that. Dial is labeled with the "Max Current" not the Breaker Size.
That Table is also misleading that you can have for example 6 AWG Romex (rated for 55A) with a breaker at 60A.
In that case you should NOT set the Wall Connector to 48A, you need to drop it to 40A.
This has been beaten to death in other threads.

That Table heading should say "Circuit Size" not "Circuit Breaker".

 

[Janus]

When you have the charger open, you may be able to see the wire the electrician pulled. You should be able to see the rating of the wire printed on the side. You can then search online to validate that the wire gauge matches the breaker.

Obviously this should have been done correctly from the start... But if they messed up the settings on the HPWC, might not hurt to double-check the rest of the work.

BTW: Should go without saying; those are live high-voltage cables... If you can't easily see the cable without shifting things around, don't stick your hand in or start pulling at cables... (Though you probably should flip the breaker before adjusting the switches anyway...)

Alternatively, you may have cable scraps in the trash can, so check there if you can't see much with the cover off.

 

[eprosenx]

Glad you posted that. Dial is labeled with the "Max Current" not the Breaker Size.
That Table is also misleading that you can have for example 6 AWG Romex (rated for 55A) with a breaker at 60A.
In that case you should NOT set the Wall Connector to 48A, you need to drop it to 40A.
This has been beaten to death in other threads.

That Table heading should say "Circuit Size" not "Circuit Breaker".

Hah, yeah, I was trying to avoid the complexity of getting into the “next size up” breaker rule.

I think in general the next size up rule should never apply to the Wall Connector since the Wall Connector does not have steps other than exact breaker sizes, so going to a 60a breaker on a wire good for 55a does not do you any good since you still have to set the Wall Connector to the 50a (40a actual to the car) setting. So there is no point in the 60a breaker (and in that case the next size up rule may not be allowed since it is not necessary).

But your point is extremely valid: The Wall Connector must be set at or below the limits of the wire in the Wall and the circuit breaker. The OP should verify this before making the change.

(and of course the capacity of the wire depends not only on the gauge of the wire, but also on the type of wire that it is... 6awg romex and 6 awg THHN in conduit have different ratings...)

 

[ronm2948]

The "dial" is in "80%" units. So just to not confuse the OP, you don't set the dial to the Breaker Size. You set it to 80% of the Breaker size (most of the time). Some breakers can be "rounded up" by 5 Amps. So the dial is set to 80% of the Minimum of the Breaker Size or Wire Capacity.

As @linkster pointed out, if they got the dial wrong what else did they mess up.

I’m a little confused ... in mine, the dial is not labeled with amps at all. It is labeled from 0-9,A-F just like the table above. You just need to read across in the table to figure out the correct setting (i.e. if it is a 40A circuit breaker, then #6 would be the setting).

 

[eprosenx]

I’m a little confused ... in mine, the dial is not labeled with amps at all. It is labeled from 0-9,A-F just like the table above. You just need to read across in the table to figure out the correct setting (i.e. if it is a 40A circuit breaker, then #6 would be the setting).

Correct.

Unless your electrician only put in wire good for 35a but used the “next size up” breaker rule to put in a 40a breaker.

That is extremely unlikely though. I would still verify it. (I would just do it visually myself, but you could also call the electrician- you should probably let them know about the setting for future reference).

 

[mswlogo]

Correct.

Unless your electrician only put in wire good for 35a but used the “next size up” breaker rule to put in a 40a breaker.

That is extremely unlikely though. I would still verify it. (I would just do it visually myself, but you could also call the electrician- you should probably let them know about the setting for future reference).

Right.

The most common case is folks using 6 AWG Romex and legally allowing a 60A breaker and using the table to set it to 9 is wrong (and confusing). It’s also a pretty common case because it’s typically the largest sizing you bother with on a Model 3 and it’s also right around 14-50 (that someone might have run 6 AWG for with a 50A breaker). They switch to Wall Connector, change breaker to 60A and think they can run 48A but they shouldn’t. It will probably work perfectly fine. But it’s 7% over the 20% safety buffer. I know people that knowingly violate it.

I know this is why you didn’t want to bring this up. I just wish that table said circuit size instead of breaker size.

 

[dmurphy]

Right.

The most common case is folks using 6 AWG Romex and legally allowing a 60A breaker and using the table to set it to 9 is wrong (and confusing). It’s also a pretty common case because it’s typically the largest sizing you bother with on a Model 3 and it’s also right around 14-50 (that someone might have run 6 AWG for with a 50A breaker). They switch to Wall Connector, change breaker to 60A and think they can run 48A but they shouldn’t. It will probably work perfectly fine. But it’s 7% over the 20% safety buffer. I know people that knowingly violate it.

I know this is why you didn’t want to bring this up. I just wish that table said circuit size instead of breaker size.

That's why we did a 20' run of #4 THHN, in 1" conduit, with a 60a breaker, and the HPWC set to 48A. Finding a competent electrician is key!

 

[eprosenx]

Right.

The most common case is folks using 6 AWG Romex and legally allowing a 60A breaker and using the table to set it to 9 is wrong (and confusing). It’s also a pretty common case because it’s typically the largest sizing you bother with on a Model 3 and it’s also right around 14-50 (that someone might have run 6 AWG for with a 50A breaker). They switch to Wall Connector, change breaker to 60A and think they can run 48A but they shouldn’t. It will probably work perfectly fine. But it’s 7% over the 20% safety buffer. I know people that knowingly violate it.

I know this is why you didn’t want to bring this up. I just wish that table said circuit size instead of breaker size.

Yeah, I agree that wording in the table is not very precise. As you point out "Circuit Ampacity" might be a better column heading. ;-)

I did want to call out that we don't know what @Niroc s wire size is. It very well could be 8 AWG Romex (NM cable), hence the 40a breaker. So assuming no other derating requirements, the proper setting would be "6" on the rotary dial.

That's why we did a 20' run of #4 THHN, in 1" conduit, with a 60a breaker, and the HPWC set to 48A. Finding a competent electrician is key!

#6 AWG copper in 3/4in conduit would have been fine too on a 60a breaker (assuming no other derating requirements for temperature or wire fill). #4 AWG is overbuilt in the situation you describe.

 

[dmurphy]

#6 AWG copper in 3/4in conduit would have been fine too on a 60a breaker (assuming no other derating requirements for temperature or wire fill). #4 AWG is overbuilt in the situation you describe.

Indeed. I wanted the #4 in case we ever decide to install a second HPWC later; I could just replace the breaker, tap at the outdoor cutout switch and add the second HPWC.

 

[SSonnentag]

This is why I do my own electrical work. I like to know it's done safely and correctly. I may over-engineer things, but I guarantee it will be safe.