Workplace 110V Charging Issue 9/12A

[dylan1016]

Hi all,

I am living at the apartment, I cannot charge my car overnight.

Luckily, my boss installed 110v outlet at parking lot and gave me a private parking spot.

He tried to install NEMA 14-50, but it couldn’t installed NEMA 14-50 due to the wiring issue.

My dailly commuting is only 7 miles one way. So, 110v charging is good to me.

These are the pictures. The outlet is installed next to spring cooler control panel.

It works well, but I could not get 12 AMP, I only could get 9/12 AMP. Is it because of wiring lengths? I think the outlet is far from breaker (+200ft),

Do you guys have any idea how to get 12 AMP?

Also, screen says check wiring and extension cable (I do not use) when door is opened.
Screen shows 12/12AMP.

After door closed, it changed to 9/12AMP

Please help me out.

Thanks

 

[compu85]

It's probably slowing down because the plug is getting too hot. I wouldn't push it and burn the plug / wiring up.

 

[timk225]

He didn't install a 110 volt outlet, he installed a 120 volt outlet. Get it right.

This outlet is probably a fair distance from the building, hence the voltage drop, but I don't know why that would limit amps. Do you ever get the "faulty wiring, current limited" notification on your car's screen?

If you close your car door and stand next to the car looking in at the center screen as it is charging, does it drop from 12 to 9 amps on the screen? Make sure the setting for it is set to 12 amps.

You're lucky to even get a slow charge, I work at a place that uses a LOT of power, I believe it has over a megawatt of capacity and my asshead manager won't let me plug in at all.

 

[dylan1016]

It's probably slowing down because the plug is getting too hot. I wouldn't push it and burn the plug / wiring up.

So, charging 9/12 Amp is safe?

 

[Alketi]

A wall outlet doesn't provide 110V, as people still say for some reason ... it provides ~120V.

So, 109V is the problem.

The voltage dropping to 109V while only pulling 9A means the Model 3 recognized a problem and dropped its current draw.

This implies the resistance is too large in the circuit or in the connection(s). Which could mean a problem anywhere along the entire run of wire. Wire is too long. Connections are poorly torqued, etc.

 

[dylan1016]

He didn't install a 110 volt outlet, he installed a 120 volt outlet. Get it right.

This outlet is probably a fair distance from the building, hence the voltage drop, but I don't know why that would limit amps. Do you ever get the "faulty wiring, current limited" notification on your car's screen?

If you close your car door and stand next to the car looking in at the center screen as it is charging, does it drop from 12 to 9 amps on the screen? Make sure the setting for it is set to 12 amps.

You're lucky to even get a slow charge, I work at a place that uses a LOT of power, I believe it has over a megawatt of capacity and my asshead manager won't let me plug in at all.

I saw error message something like "Charging Speed Reduced , check extension cable ......" I will upload picture later.

 

[dylan1016]

A wall outlet doesn't provide 110V, as people still say for some reason ... it provides ~120V.

So, 109V is the problem.

The voltage dropping to 109V while only pulling 9A means the Model 3 recognized a problem and dropped its current draw.

This implies the resistance is too large in the circuit or in the connection(s). Which could mean a problem anywhere along the entire run of wire. Wire is too long. Connections are poorly torqued, etc.

Is is safe to using it?

What should I do if this is dangerous?

 

[Big Earl]

Is is safe to using it?

What should I do if this is dangerous?

It should be checked out to make sure it’s safe. As mentioned, the car is limiting its current because of the voltage drop. This can be due to a number of factors ranging from benign (long wire length) to concerning (improper or loose connections).

If your boss wants to be awesome, he’ll call an electrician out to upgrade the wiring, but that will probably be very expensive. It would be better to run a dedicated 240 volt line out to a parking space and install a charging station (or better get, a dual head charging station that can share one circuit between two vehicles), but that’s also expensive.

 

[srs5694]

He tried to install NEMA 14-50, but it couldn’t installed NEMA 14-50 due to the wiring issue.

It's not clear what "the wiring issue" is, but if this is a dedicated 120v run, then my understanding is that it can probably be easily bumped up to 240v, so long as the amperage remains the same. This would double your charging speed -- maybe more, if the wiring is rated for 20A. The electrician would need to replace the outlet with a 240v, 15A (or 20A), 3-wire standard, like a NEMA 6-15 or NEMA 6-20; and you'd need to buy the matching adapter from Tesla for $35. On the other end, the breaker would need to be replaced with a 240v unit.

Of course, this assumes that whatever is causing the drop from 12A to 9A is fixed. Also, if it's not a dedicated run, this approach would not work -- at least, not without sacrificing or re-wiring whatever else is on the same circuit.

 

[Cosmacelf]

What the car is sensing is that there is too much of a voltage drop from when it starts to charge (when it just starts charging and isn’t drawing any power) to when it is drawing 12A. It would be helpful if you could tell us what voltage the car senses when you first start to charge. When it is drawing 0 out of 12A (0/12).

Basically if there is too large a voltage drop, the car thinks there might be something wrong with the receptacle and thus reduces power. However if your case, since you said it was a new receptacle, the problem is probably that the electrician used a thinner gauge wire than he should have given the intended usage.

Since the electrician couldn’t install a 14-50, I am betting that he used an available conduit (correct? Was there any trenching involved in the receptacle install?). And it’s probably a 1/2 inch conduit. And for such a long run, he probably got lazy and installed 14 gauge wire instead of 12 gauge since that’s all you “need” for a 15A circuit. But the long run makes the voltage drop when drawing 12A.

If I am correct, there isn’t a safety issue. The voltage drop occurs solely to the long length of thin for the distance wiring.

At any rate, I would ask that an electrician look at the receptacle to make sure it is installed correctly (use the screw terminals, not the stab terminals, this is important), and also ask him if it is possible to upgrade the wire if the receptacle looks ok.

Otherwise, you’ll be stuck at 8A or whatever.

 

[Cosmacelf]

Oh, and what srs said makes sense too. IF there is only this ONE receptacle on the circuit (breaker), then you could swap the receptacle out for a nema 6-15 and swap the breaker out for a 240v, 15A breaker, and then you could use Tesla’s $35 nema 6-15 adapter to charge and it would double your charge speed. Maybe something to ask the electrician if he comes out.

 

[Big Earl]

It's not clear what "the wiring issue" is, but if this is a dedicated 120v run, then my understanding is that it can probably be easily bumped up to 240v, so long as the amperage remains the same. This would double your charging speed -- maybe more, if the wiring is rated for 20A. The electrician would need to replace the outlet with a 240v, 15A (or 20A), 3-wire standard, like a NEMA 6-15 or NEMA 6-20; and you'd need to buy the matching adapter from Tesla for $35. On the other end, the breaker would need to be replaced with a 240v unit.

Of course, this assumes that whatever is causing the drop from 12A to 9A is fixed. Also, if it's not a dedicated run, this approach would not work -- at least, not without sacrificing or re-wiring whatever else is on the same circuit.

That circuit is likely powering the irrigation system controller, so turning it into a 240 volt circuit probably isn't going to work.

 

[Cosmacelf]

That circuit is likely powering the irrigation system controller, so turning it into a 240 volt circuit probably isn't going to work.

Bingo. I hadn't put 2+2 together. The wiring and conduit were probably already there, all the electrician did was probably just install a receptacle off the circuit.

 

[timk225]

Those photos are too far away to get any detail, but that's what it looks like to me, they just added an outlet to the irrigation system. You need a good 5-20 outlet, on 12 gauge wire, all to yourself. Get better photos.

Offer to share the cost of installing with your boss, that might make it easier. And if it is a 200 foot run, even going to 10 gauge would help with the voltage drop.

 

[dylan1016]

It's not clear what "the wiring issue" is, but if this is a dedicated 120v run, then my understanding is that it can probably be easily bumped up to 240v, so long as the amperage remains the same. This would double your charging speed -- maybe more, if the wiring is rated for 20A. The electrician would need to replace the outlet with a 240v, 15A (or 20A), 3-wire standard, like a NEMA 6-15 or NEMA 6-20; and you'd need to buy the matching adapter from Tesla for $35. On the other end, the breaker would need to be replaced with a 240v unit.

Of course, this assumes that whatever is causing the drop from 12A to 9A is fixed. Also, if it's not a dedicated run, this approach would not work -- at least, not without sacrificing or re-wiring whatever else is on the same circuit.

The wiring issue means, the wire is came from building through under the ground. This wire was only for our spring cooler system.
If I install the NEMA 14-50, they will charge more than $1,000. I do not want to ask my company pays more than $1,000 for installation.
For 110v outlet install, they charged only $150. That is why I would like to stick with 110V charging method.

 

[dylan1016]

Those photos are too far away to get any detail, but that's what it looks like to me, they just added an outlet to the irrigation system. You need a good 5-20 outlet, on 12 gauge wire, all to yourself. Get better photos.

Offer to share the cost of installing with your boss, that might make it easier. And if it is a 200 foot run, even going to 10 gauge would help with the voltage drop.

I think the electrician just added 110v outlet on irrigation system.
it charges $150 labor + $100 parts

 

[Jonabramson]

$150 for labor and $100 for parts to drill a hole in the irrigation box and add another outside box with a likely GFI 120v dual plug. Maybe that's the going rate in that area. Seems a bit high to me though. If you'll be there a long time, you'll save over time if you pay for the wiring to be pulled to the location. As to safety, I don't think the voltage drop is an issue. I do recall that someone posted though that using 120v outlet only at home to charge temporarily effected the reported range. Maybe someone else can recall that?

 

[Alketi]

OP, you need to understand how long the wire is and how it's run. I would recommend calling the electrician and telling him that you're getting an 11V drop when pulling only 9A and asking him to come back and look at it.

Note that you won't see the drop if you just use a voltmeter at the outlet -- it needs to be pulling current for the resistance to affect it.

 

[KenC]

It's fine. You only need 1kW an hour. 8 to 9 hrs later and you've gotten 8 to 9kWh, about 12%, which is more than you need on a daily basis.

 

[mswlogo]

I suspect it's fine too. It's probably due to it being a very long run.
For that long a run you often go up a gauge (#12 for a 15A circuit for example).

It won't hurt to have it checked out but it's likely the long run.

If this outlet is dedicated for you (nothing else on it), I would ask that it be switched to a 240V (NEMA 6-15).
Easy breezy to change to 240V and perfectly safe (even if it still has the 12% voltage drop).

But they might have tapped off an existing 120V circuit out in the parking lot, probably already a long run, like a light post or something.

It should go without saying it should be GFCI protected (for either 120V or 240V).