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Installed Nema 1450 outlet

I finally got it done nine months after getting the Model S. I installed 100 amp service to the garage and a 50 amp, Nema 1450 outlet to charge the car.

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I'm sure I'm not the first to do it, but I haven't seen it elsewhere. I installed the outlet/mobile adapter on the ceiling. This way, it's never hanging across my garage opening, where we walk.

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I had a long run from the electrical box to the garage, and my basement is finished. That's why I decided to run 100-amp service - as future proofing more than anything else. To be honest, I'm not sure I'd bother if I was doing it again. The #3 wire was quite a bit more expensive, and it was pretty hard to fish through the wall and manipulate it to wire it into each box.

I did this with the help of my dad. Pretty much two to three days of work. It cost me about $500-600 in materials. I was quote $2300 by an electrician to do the work. I'm pretty happy with the result.
 
Definitely a unique install with the outlet on the roof, just make sure the weight of the cord isn’t cause for the prongs to become unseated. Don’t want the resistance to climb and cause the outlet to overheat.

Also, wonder what wire insulation type you purchased. You mentioned this is a dedicated 100A EV circuit with #3 wire, but be mindful NEC requires the circuit to be derated. As such it is really sized for a continuous 80A load (100A * 0.80) less I mention voltage drop and ambient temperature considerations.
 
Definitely a unique install with the outlet on the roof, just make sure the weight of the cord isn’t cause for the prongs to become unseated. Don’t want the resistance to climb and cause the outlet to overheat.

Also, wonder what wire insulation type you purchased. You mentioned this is a dedicated 100A EV circuit with #3 wire, but be mindful NEC requires the circuit to be derated. As such it is really sized for a continuous 80A load (100A * 0.80) less I mention voltage drop and ambient temperature considerations.


All great points. The adapter is secured to the ceiling so there is no weight on the outlet or the adapter cords.

As far as the cable gauge, this was the side that the electrician was planning to run. Also, checked with the father in law who is an electrician and he said #3 wire is good. I believe he said it's actually rated up to 120 amps.

So it's #3 wire to the panel, but #6 wire from the panel to the outlet (50 amps).
 
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Not trying to be argumentative, just desire to arm you with some knowledge. I also appreciate assurances your FIL and contractor provided but sometimes it’s best to understand the code and engineering principles if you’re like me—an avid DIY guy.

I’m not sure why anyone would tell you that circuit is good for a continuous 100A load (3hr plus)—it is NOT. I suspect they are sizing the conductors as a standard duty branch circuit.

Your circuit will work fine for your current setup, but it is most certainly not future proof, nor capable of supporting a continuous 100A load. You would have needed to install a #1 AWG with 75c insulation rating of THW, THWN.

Just want you to understand what you have so you’re aware of the potential hazards if pushing more than 80A through that circuit.

If credentials matter i “call and raise” your FIL & contractor with my engineering degree, professional engineers license, and 20+ years of consulting and construction experience. Just saying, and really not trying to be a smart ass. Just looking out for you and your family’s well-being.

Reference that I pulled off the web:
Encore Wire Corporation- Wire Size Table 310.15(b)(16)

Overcurrent Protection: EVSE feeders and branch circuits must be sized for continuous duty and have a rating no less than 125% of the maximum load of the EVSE. Where noncontinuous loads are supplied from the same feeder or branch circuit, such as the ventilation system, the overcurrent device must have a rating no less than the sum of the noncontinuous loads plus 125% of the continuous loads (CEC §625.21).

Article 100: "Continuous Load: A load where the maximum current is expected to continue for 3 hours or more."

210.19(A) (Branch Circuits Not More Than 600 Volts): "Branch-circuit conductors shall have an ampacity not less than the maximum load to be served. Where a branch circuit supplies continuous loads or any combination of continuous and noncontinuous loads, the minimum branch-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load."

NEC 625.21 (2011) or 625.41 (2017) requires all EV charging circuits to be upsized by 25%; ie, you must treat all EV charging as a continuous load, regardless of charge session duration
 
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boaterva

Well-Known Member
Supporting Member
Makes no sense to me at all. Looks like tons of room to put the outlet between the doors or for almost the same price install a wall connector (since I assume this is a permanent installation).

Only reason to have it on the ceiling would be if it were a one piece door with no wall surface, which is what we have (see sig) and we use two HPWCs with long cords on the outside walls, one for each car on 100 A shared circuit. (And yes with larger wire.)
 

Rocky_H

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Feb 19, 2015
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Boise, ID
Not trying to be argumentative,
Well you are failing miserably, and that is exactly what you are doing.

I’m not sure why anyone would tell you that circuit is good for a continuous 100A load (3hr plus)—it is NOT. I suspect they are sizing the conductors as a standard duty branch circuit.

Your circuit will work fine for your current setup, but it is most certainly not future proof, nor capable of supporting a continuous 100A load. You would have needed to install a #1 AWG with 75c insulation rating of THW, THWN.
Paste the quote where ANYONE said this was for a 100A continuous load! It's not there. No one said that. You are falsely putting words in someone's mouth and then pointing a finger at them to accuse them of being wrong in this statement that you made up out of thin air and attributed to them. They simply talked about it being a 100A circuit, and that's what it is what it would be rated as. Your information about code etc. is correct, so I am sparing you the disagree rating, but your accusations and claims are false and rude.
 
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”...Well you are failing miserably...


Paste the quote where ANYONE said this was for a 100A continuous load...You are falsely putting words in someone's mouth...They simply talked about it being a 100A circuit, and that's what it is what it would be rated as...Your information about code etc. is correct...”

I too disagree with your post but feel free to attack away...

The OP indicated he is running a dedicated 100A circuit which happens to be used as a charge point for an EV. Then by the statement of future proof implies that will be expanded to cover other uses, most likely another EV. That by the nature of its use is a continuously load.

By the nature of the OPs second post it substantiated this perceived intended use. If this was not his intent then perhaps we would have seen the OP refute my original assumption.

He went on to further indicate two “guys” said it was ok. I’ve seen this conduct before, by both contractors and engineers, and ones spoken word is not proof of a proper design or code compliance.

At any rate, thanks for your opinions on the matter. Nice to see you too care about the members of this community and I’m sure the OP now has a better understanding of how much load he can place on the circuit.
 
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Rocky_H

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Feb 19, 2015
7,835
9,856
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I too disagree with your post but feel free to attack away...
Don't even... You made false accusations, and I pointed out it was inappropriate.

The OP indicated he is running a dedicated 100A circuit which happens to be used as a charge point for an EV. Then by the statement of future proof implies that will be expanded to cover other uses, most likely another EV. That by the nature of its use is a continuously load.
They are continuous loads, but it is you who made up the claim about the amount. As you just mentioned, they want to leave some amount of overhead for future increases. But maybe that only is only totaling 60 or 70 amps continuous. That would be allowed continuous load within a 100A rated circuit.

He went on to further indicate two “guys” said it was ok. I’ve seen this conduct before, by both contractors and engineers, and ones spoken word is not proof of a proper design or code compliance.
"what" was OK? He only mentioned running a 100A rated circuit for right now and using only part of the capacity for right now. That is totally appropriate and shows no intent to do anything that would violate code. Where are you getting this false conclusion?

Why are you jumping to these unfounded conclusions that they are intending some nefarious code violations? They have made no indication at all of that.
 
Sublimobile, do you have the newer UMC that derates NEMA 14-50 current from 40 amps to 32? In 2017, I installed a similar charging receptacle in my garage and it delivers 40 amps for 29 mi/hr. I think Tesla discovered its NEMA adapter got too warm at 40 amps, so derated it by launching a new UMC model. Mine gets warm, but not hot after several hours.
 
Sublimobile, do you have the newer UMC that derates NEMA 14-50 current from 40 amps to 32? In 2017, I installed a similar charging receptacle in my garage and it delivers 40 amps for 29 mi/hr. I think Tesla discovered its NEMA adapter got too warm at 40 amps, so derated it by launching a new UMC model. Mine gets warm, but not hot after several hours.


I believe I have the older UMC. It believe it charges at 40 amps, but I'll have to make sure on that.

I'll keep an eye on the charger to see if it's getting warm. Thanks for the heads up.
 
The only problem I see is if you want to take the mobile charging cord with you on a trip or somewhere you may need the cord, it would be difficult to reach to keep unplugging and plugging in. Unless you have a 2nd mobile charging cord.
This is definitely the case. I would need a second charger if I wanted to take it with me. I don't drive long distance much and I've gone without it the few times Ive driven somewhat far. The superchargers are common enough that it wasn't a major concern.
 
Based on photos showing NEMA adapter at the ceiling, it appears OP leaves UMC plugged in all the time. Hopefully he has a 2nd UMC for road trips or installed a high quality receptacle. The low cost HD receptacle is designed for very few insertions before it develops resistance and heat. This forum has shown melted adapters from misuse.
 
Based on photos showing NEMA adapter at the ceiling, it appears OP leaves UMC plugged in all the time. Hopefully he has a 2nd UMC for road trips or installed a high quality receptacle. The low cost HD receptacle is designed for very few insertions before it develops resistance and heat. This forum has shown melted adapters from misuse.
It's a cheapo from Depot outlet.
 
It's a cheapo from Depot outlet.

That's the same one I installed and it works fine. As many have mentioned, don't unplug NEMA adapter more than a few times annually. Periodicaly, check it for heat after two hours of charging. If very warm, replace receptacle. One year after installing the HD receptacle, I discovered some of its wire terminals needed tightening. Perplexed how they could loosen and potentially heat-up!
 
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That's the same one I installed and it works fine. As many have mentioned, don't unplug NEMA adapter more than a few times annually. Periodicaly, check it for heat after two hours of charging. If very warm, replace receptacle. One year after installing the HD receptacle, I discovered some of its wire terminals needed tightening. Perplexed how they could loosen and potentially heat-up!
Repeated heating and cooling can easily cause the connections to loosen, especially if they are not adequately tightened in the first place.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
7,835
9,856
Boise, ID
That's the same one I installed and it works fine. As many have mentioned, don't unplug NEMA adapter more than a few times annually. Periodicaly, check it for heat after two hours of charging. If very warm, replace receptacle. One year after installing the HD receptacle, I discovered some of its wire terminals needed tightening. Perplexed how they could loosen and potentially heat-up!
Yes, they can be OK if you don't plug and unplug a lot. I hadn't bothered to check what kind mine was until recently, and it's the cheap Leviton one. But it has been fine for over 5 years. (Note: I also wasn't running it at the full 40A I could have. I've had it turned down to about 31 or 32 amps just to save some heating on my UMC.) I didn't bother to check or replace it because I earned one of the signature wall connectors from a referral and was thinking I would replace the outlet with that. So I waited...and waited...and waited... I finally got it after a 14 month wait, so now I am going to find out the parts I need to mount that.
 
Repeated heating and cooling can easily cause the connections to loosen, especially if they are not adequately tightened in the first place.
Even if tightened to spec the repeated expansion and contraction of the heating and cooling can loosen the terminals, this is one reason I really like the Hubbell/Bryant 14-50 receptacle as it uses allen screws with triple the torque rating
 

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