new wall charger confusion

[EVer Hopeful]

When is the one time you get your car properly cleaned inside and out including the engine bay and the cupholders and vacuuming under the seats?

The answer of course is - When you're trying to sell it!


So you end up valeting the vehicle for someone else,

...but the good news is that the guy you bought it from did the one-proper-cleaning and YOU got the benefit of it!

 

[Rocky_H]

I decided to use 6/2 and have 60amps breaker installed by replacing the 2 thick breakers to tandem breaker router.

Romex, you mean? You can't use 6 gauge of that for a 60A circuit. If it's MC cable, though, that does have a higher amp rating, and that would be OK.

 

[shyboy]

True. But you’d set the Wall Connector to 50A circuit (40A charging). Since there is no 55A setting.

If it’s a 200A panel I doubt your over load limit. If it’s 100A panel, forget adding a 60A you need a new service. You might squeeze a 20-30A 240v though.

Regardless of load, your panels are at max for crowding. I’d seriously consider getting a new, much larger panel if 200A and a whole new service if 100A.

You can stretch / squeeze a smaller circuit but that is really packed already.

If already 200A a new Subpanel would be the next best option. But to me, that’s money down the drain. You need a new main panel and get rid of sub panel (band-aide).

Advice you got isn’t bad, but a major circuit might trigger bringing everything up to a better level. All for good reason. Varies by inspector. He might declare it already a mess.

So don’t think of it as cost to get your EV. It’s lumping in getting your panel cleaned up first.

It’s not terrible, but close and adding more is really pushing it.

This is 200A service.

My main breaker is 200A and I also checked this with utility company and they confirmed I have 200A service.
Just to replace the panel, labor cost is $5k. TESLA shows 5 years gas saving is around $6k in 5 years.
I would get the panel fixed if I plan to stay in this house longer. Can't justify the cost for panel upgrade.

Another option was given to me is to upgrade the subpanel and accommodate the new breaker in the sub panel. But if its overload then adding the breaking into subpanel would still overloading the main panel. No?

The other option I was thinking to just use extension wire to the dryer outlet NEMA 14-30 // not ideal but work around maybe until I have high mileage commute.

 

[shyboy]

Romex, you mean? You can't use 6 gauge of that for a 60A circuit. If it's MC cable, though, that does have a higher amp rating, and that would be OK.

I meant 6/2 Romex.
Are you saying if I use 6/2 Romex I will not able to get 60A?

Do you recommend using 2 single THHN wires and a ground in MC to get 60A?

 

[Rocky_H]

I meant 6/2 Romex.

Right--can't do that.

Are you saying if I use 6/2 Romex I will not able to get 60A?

It doesn't have an amp rating that allows it to be used for a 60A circuit. It's only 55A rated at 6 gauge.

Do you recommend using 2 single THHN wires and a ground in MC to get 60A?

I'm not recommending any specific thing. But you just need to use something that meets the rating for the circuit you're trying to use it with.

Here: this is a table of the amp ratings for various things. Romex (NM-B) is in the first column, under the 60 degrees C. The wire in conduit things, like THHN are in the 75 degrees C column. I think metal clad cable (MC) is also used as in that 75 degrees C column.

Cerrowire Resources - Ampacity Charts

Ampacity is the maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating. Cerrowire's ampacity chart helps calculate the load requirement for a circuit.

www.cerrowire.com

So there is nothing wrong with using 6/2 Romex for a circuit, but it can't be a 60A circuit. It only has a 55A allowed rating. So you can use a 50A breaker, and set the wall connector or whatever to supply 40A, and it's fine.

Or if you want to switch to wires in conduit, you can see that 6 gauge size of that has a 65A rating. So that would meet the rating for a 60A circuit.

 

[Sophias_dad]

Another option was given to me is to upgrade the subpanel and accommodate the new breaker in the sub panel. But if its overload then adding the breaking into subpanel would still overloading the main panel. No?

Yes, the subpanel has no generation facilities built in, so if the circuits(except the one for the subpanel) in the main panel plus the circuits in the subpanel add up to a predicted load of >200A, you have a good chance of tripping the main.

You absolutely, positively can't just add up the numbers on the breakers to get a load prediction. Doing that right now would get you to 400A or something equally heinous. Equally, with a very few exceptions you aren't allowed to make statements like "oh, I'll never use appliance X at the same time I'm using appliance Y, or when I'm charging my Tesla). The exceptions are things like heat and air conditioning, where you can reliably predict they are not going to run at the same time and they(heat and AC) are automatic in their usage.

 

[EVer Hopeful]

The exceptions are things like heat and air conditioning, where you can reliably predict they are not going to run at the same time and they(heat and AC) are automatic in their usage.

...but if you just wanted to be warm, then you'd mix hot and cold

The whole 55A thing reminds me of an aircraft certification where it was designed for say 300 people and the FAA makes them do a test: put the thing in a dark hangar, fill it with extras, then after everyone is comfortable, sound the bell, blow the slides and get everyone out within 60 seconds. Apparently one person balked at the door, so they only got 299 peeps out to safety and it was easier to just take the hit and have the certification for 299 rather than do it all over again. Probably apocryphal , but I can see someone running a test and getting some weird result that said 55A and that result stuck

 

[fiehlsport]

I believe that load center is maxed out. I have the same one and it has a limit of eight Tandem breakers. Looks like it's already got that, if not more. 200A may suffice, but you probably need a larger subpanel to support another 240V breaker.

 

[mswlogo]

This is 200A service.

My main breaker is 200A and I also checked this with utility company and they confirmed I have 200A service.
Just to replace the panel, labor cost is $5k. TESLA shows 5 years gas saving is around $6k in 5 years.
I would get the panel fixed if I plan to stay in this house longer. Can't justify the cost for panel upgrade.

Another option was given to me is to upgrade the subpanel and accommodate the new breaker in the sub panel. But if its overload then adding the breaking into subpanel would still overloading the main panel. No?

The other option I was thinking to just use extension wire to the dryer outlet NEMA 14-30 // not ideal but work around maybe until I have high mileage commute.

If you have 200A that’s great.

That’s a total rip off replacing that panel for $5k. It’s 2 days work tops and $500 tops for panel and breakers. So $1500 tops.

Shop around. Lots of service people are gouging like crazy. Believe me I know, just finished building a house.

It will be almost half the work replacing the sub panel and it will still be a huge mess.

 

[Mrbrock]

If you have 200A that’s great.

That’s a total rip off replacing that panel for $5k. It’s 2 days work tops and $500 tops for panel and breakers. So $1500 tops.

Shop around. Lots of service people are gouging like crazy. Believe me I know, just finished building a house.

It will be almost half the work replacing the sub panel and it will still be a huge mess.

Skilled labor for $60 an hour? Plus permit fees? Good luck.

 

[shyboy]

So here are full details along with the picture of my current setup.

I used 6/2 MC wire which ran 100 feet exact.
Only used conduit in my garage. Electrican said no need to run the conduit in the garage toward the panel.

Electrician came and replace the 2 big breakers with tandem breaker and install the 60amps breaker for WC.

Using it for 2 months now with about 15 charge cycles,
There is no issue I see so far.

Currently WC is charging on 48 amps.

I started the charging the other day and used infrared temp reader and check the wire temperature after 1 hour charging, the wire temp was 82F.

It seems so good so far.

I didn't pull the permit.

 

[fiehlsport]

Nice conduit work!

 

[Sophias_dad]

So here are full details along with the picture of my current setup.

I used 6/2 MC wire which ran 100 feet exact.
Only used conduit in my garage. Electrican said no need to run the conduit in the garage toward the panel.

Electrician came and replace the 2 big breakers with tandem breaker and install the 60amps breaker for WC.

Using it for 2 months now with about 15 charge cycles,
There is no issue I see so far.

Currently WC is charging on 48 amps.

I started the charging the other day and used infrared temp reader and check the wire temperature after 1 hour charging, the wire temp was 82F.

It seems so good so far.

I didn't pull the permit.

Welcome to the land of non-compliance but not caring. That 6/2 NMB isn't rated for 48A continuously per the NEC. I also don't think its supposed to be run through conduit inside a garage, since that's considered a damp or wet location. I'm not a professional.

You might be missing a staple or three for the NMB that's free-hanging. I think its supposed to be tacked down or otherwise supported every three feet plus within a foot or something(might be 6" for an outlet) of each terminating device. I think that along its length, the holes it passes through count as 'support' so there shouldn't be a need for stapling there. I'm still not a professional.

That conduit looks too small for the 6/2 that's running through it, although if it had transitioned to THHN it would be fine.

 

[fiehlsport]

Welcome to the land of non-compliance but not caring. That 6/2 NMB isn't rated for 48A continuously per the NEC. I also don't think its supposed to be run through conduit inside a garage, since that's considered a damp or wet location. I'm not a professional.

You might be missing a staple or three for the NMB that's free-hanging. I think its supposed to be tacked down or otherwise supported every three feet plus within a foot or something(might be 6" for an outlet) of each terminating device. I think that along its length, the holes it passes through count as 'support' so there shouldn't be a need for stapling there. I'm still not a professional.

That conduit looks too small for the 6/2 that's running through it, although if it had transitioned to THHN it would be fine.

Good catch, I was tired this morning and didn't even realize it was NM, not MC like the poster said.... I believe conduit is allowed but only for short distances for protection. NM in conduit for the majority of the run is definitely not ideal. It would need to be 3/4" conduit minimum for (2) #6 and a single #10 ground, but NM isn't something you can calculate for fill since that's not typically a product you put in conduit to begin with.

So yeah, this setup should be capped at 40A max. Which has been mentioned in this thread before. Not 48 - your electrician should have caught this and only put it on a 50A breaker as soon as the romex was brought into the equation. They should know better.'

AND the 100' run - you may need a larger conductor from this alone due to the voltage drop, not to mention the slightly added heat from the conduit and the romex sheathing that shouldn't be there.

Worst case scenario, it's not even the peak of summer yet. When this garage is 100-120 degrees, that romex in the pipe is going to be toasty charging at 48A, which it is not permitted to do for a continuous load, even if it wasn't in pipe.

There is more than one factor which makes this WC install not to code here, even at 40A.

 

[EVer Hopeful]

I like the OQ breakers, but what's the deal with #22?

Looks like something to stop it being set to ON

 

[Eric33432]

I have seen many electricians, even the ones on Tesla's approved list, install #6 NM on a 60 amp breaker, with the TWC set for 48 amp charging. I have a friend who had two such TWCs installed in his garage by a Tesla recommended electrician, initially set to 48 amp charging. He also told me his Tesla approved electrician did not pull permits. He has since set them for 40 amp charging and his cars are always fully charged in the morning, and sometimes they both charge at the same time. And he lives in a 4,000+ s.f. house built in 2015 which just has a 200 amp service, but has gas heat and hot water.

I think the reason a lot of electricians do this is this breaker/wire combination is what is regularly used for air handlers that have a 9,600 watt electric heat strip, and are drawing less than 44 amps, which is fine for #6 wire, and the much mis-used "round up rule" allows for this. But the air handler's electric heat cannot be configured for a higher wattage and amp draw.

If the OP wants to make this completely safe, running it at 40 amps to charge would be a good thing. I am not sure if keeping it on a 60 amp breaker is acceptable in this situation, but it is acceptable for the above referenced electric heat installation, and it would be safer than running at 48 amps.

The other question is: is NM cable installed in the conduit? That is not allowed, because the NM is designed to be in free air and installing it in conduit would trap heat. Hopefully OP transitioned to TNNH/THWN-2 for the wires in the conduit run.

I think #6 wire would be OK regarding voltage drop. 100 feet of #6 copper will only have 1.77% voltage drop at 48 amps, 1.47% at 40 amps.

But it is a pretty conduit installation!

I state this for anyone who comes upon this and is looking for advice:

If you want a 60 amp breaker, 48 amp charging, and #6 wire run THHN/THWN-2 in conduit or if conduit is too much work run MC cable. If MC cable is too much work, install a 50 amp breaker with your #6 NM cable and configure the TWC to charge at 40 amps.

Here are some photos of what I did.

Conduit for the first one. I cut open the sheet rock to install the conduit into the middle panel and fixed the sheet rock.

The grey box disconnects charging if I am running on my 60 kW generator and it becomes overloaded. If the generator is not overloaded, the car will charge while on generator.

MC cable for the second one, across the garage. I fished the wire down inside the wall to the left panel and repaired the sheet rock.

Runs across the garage, over the doors. Installing conduit here would have been difficult:

Short run of conduit from generator load share device to the TWC:

 

[Mrbrock]

Not saying one should do this, but the wiring inside the sheath for 6/2 NMB is the same as 6# THHN, so the sheathing could be removed for a short section that needs to be in conduit. However, it is not marked like normal THHN is so it is not acceptable to remove from the sheathing since there are no markings to identify wire size.

 

[h2ofun]

I just am amazed at the folks who push back saying who cares. Or the installer who do not know the rules!
I found out after my solar installers race 6/2 NM from my inverter to my panel via a 60 amp breaker. Long story but found out this is only
good for 55 amps. I called the inspector who approved and he said he would research. He called back and said he did not know it was wrong. He said he would call the installer and say they either could replace with 4/3 NM, which is REAL expensive, or he would void the approved permit, which he said he had never done. The installer came out and replace with 4/3 NM, just the cable was like 4K.
So when I went to have my EV 200 amp subpanel installed and 5 EV charging locations, they wanted to run 6/3 NM. I said nope, not to spec.
So they ran #6 thhn, 90C in MC, so now I am good to spec to 75amps!!
I just installed my first Gen 3 wall connector with a 60 amp breaker. I sleep well at night since I know it is to code! I have my second Gen 3 on order. Not sure how many of the 5 I will do, for fun

 

[Mrbrock]

I just am amazed at the folks who push back saying who cares. Or the installer who do not know the rules!
I found out after my solar installers race 6/2 NM from my inverter to my panel via a 60 amp breaker. Long story but found out this is only
good for 55 amps. I called the inspector who approved and he said he would research. He called back and said he did not know it was wrong. He said he would call the installer and say they either could replace with 4/3 NM, which is REAL expensive, or he would void the approved permit, which he said he had never done. The installer came out and replace with 4/3 NM, just the cable was like 4K.
So when I went to have my EV 200 amp subpanel installed and 5 EV charging locations, they wanted to run 6/3 NM. I said nope, not to spec.
So they ran #6 thhn, 90C in MC, so now I am good to spec to 75amps!!
I just installed my first Gen 3 wall connector with a 60 amp breaker. I sleep well at night since I know it is to code! I have my second Gen 3 on order. Not sure how many of the 5 I will do, for fun

Was the NMB for solar in wall? Could they have used #6 MC? Would have been cheaper than 4/3 NMB. And you have a 400ft run from your panel to the inverter?

 

[MattM24]

I just am amazed at the folks who push back saying who cares. Or the installer who do not know the rules!
I found out after my solar installers race 6/2 NM from my inverter to my panel via a 60 amp breaker. Long story but found out this is only
good for 55 amps. I called the inspector who approved and he said he would research. He called back and said he did not know it was wrong. He said he would call the installer and say they either could replace with 4/3 NM, which is REAL expensive, or he would void the approved permit, which he said he had never done. The installer came out and replace with 4/3 NM, just the cable was like 4K.
So when I went to have my EV 200 amp subpanel installed and 5 EV charging locations, they wanted to run 6/3 NM. I said nope, not to spec.
So they ran #6 thhn, 90C in MC, so now I am good to spec to 75amps!!
I just installed my first Gen 3 wall connector with a 60 amp breaker. I sleep well at night since I know it is to code! I have my second Gen 3 on order. Not sure how many of the 5 I will do, for fun

Residential breakers are rated for 60C/75C, not 90C, so while having the 90C wire is good for derating, it cannot be used above its 75C rating in this case.

The whole system is only as good as its lowest temperature rating.