Hey everyone, thanks in advance for the advice. I need to install a home charger next to my driveway, about 30 or so feet from my house. No garage. I understand that (depending on the amps I can deliver to the charger) the HPWC could charge my forthcoming M3 AWD faster than the 14-50, but I was wondering if anyone had experience with this decision? I would think that getting an electrician to install an outdoor 14-50 box would be simpler than the HPWC, but then I’d have to use the mobile charging cable every day. Anyway, hoping someone else in here had a similar dilemma and might have some insight. Thanks again!
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
HPWC vs NEMA 14-50 for outdoor home charger?
- Thread starter tentimesodds
- Start date
Knightshade
Well-Known Member
A second set of OEM charging cables is $300 (so you can leave the other set in the car all the time), the HPWC is $500. The difference in speed is pretty small, small enough that if you're charging overnight it won't make a difference.
Plus if you move you can more easily take the spare set of cables with you- and tell the new home buyer they can use the 240 plug for a hot tub
Plus if you move you can more easily take the spare set of cables with you- and tell the new home buyer they can use the 240 plug for a hot tub
If you go with the HPWC and the same wiring you can charge at 40amp instead of 32 and yes the connector was $200 more than a spare UMC but you also saved $30-50 on the outdoor rated 14-50 box.
The price to upgrade wiring to use all 48amp capabilities of the onboard charger would be marginal once an electrician is involved.
All in have to think the difference between a HPWC on a 60amp circuit giving you 48 to the car vs a spare UMC at 32amp on a 50amp 14-50 is probably only $250.
I do believe a redundant charging option is a prudent decision.
Obviously if you are just going to get by on a single UMC then the price difference goes up another $300.
The price to upgrade wiring to use all 48amp capabilities of the onboard charger would be marginal once an electrician is involved.
All in have to think the difference between a HPWC on a 60amp circuit giving you 48 to the car vs a spare UMC at 32amp on a 50amp 14-50 is probably only $250.
I do believe a redundant charging option is a prudent decision.
Obviously if you are just going to get by on a single UMC then the price difference goes up another $300.
Also, HPWC is weather-proof end-to-end; harder to steal; ready to share with a second HPWC.
We charge in our driveway, not worried in rain or snow. Do try to clear snow out of port area before unplugging cable.
We charge in our driveway, not worried in rain or snow. Do try to clear snow out of port area before unplugging cable.
eprosenx
Active Member
I *highly* recommend the HPWC route. I always want a UMC in the car with me and so that would mean unplugging it every day which you don't really want to do since NEMA 14-50 was not really designed for that many plug/unplug cycles (some receptacles are better than others, but still...). So that means the delta cost is $500 vs. $300 - so only $200 for the hardware. You also don't have to worry about getting shocked since the UMC to NEMA plug connection is not GFCI protected (downstream of the UMC is, but that is only half the battle). A HPWC is hard wired in so much harder to come in contact with non-GFCI protected wire.
As others have mentioned, you also don't have to worry as much about theft on the HPWC since it is firmly bolted in. The whole setup is just more robust too (cable, etc...)
The difference in speed is 48a vs. 32a. I would personally not call a 50% improvement "small", but everything is relative. Most folks can charge comfortably overnight using just 32a. I personally did not mind spending the extra couple hundred bucks to get the HPWC (I did all the install myself so there really was very little difference in cost - and actually, yeah, the savings on the 14-50 outdoor rated box brings my cost delta down to like $150. Since I ran it in conduit, I was able to use 6 AWG for the 60a HPWC circuit.
You can always wall plate it over if you take the HPWC with you. Or, if you want to advertise it as a selling feature then just install a NEMA 6-50 receptacle. No neutral needed. Frankly, the neutral is just a waste of money since EV's will never need it. (the one reason to do 14-50 would be because many cars/EVSE's including the Tesla's come with that plug style - though they sell the $35 adapter for 6-50 - another reason to use a 14-50 is in case you want to actually be able to plug in an RV).
eprosenx
Active Member
This is technically possible, but not code compliant based on my reading of the code.
1. You have to follow manufacturers instructions and Tesla does not say go install a pigtail (they DO say to hardwire it).
2. Pigtails per NEC are only allowed on EVSE's that are "fixed in place" (i.e. it can't require tools to move it).
3. Pigtails are allowed on some manufactured equipment if it is "fixed in place" (not fastened in place), but they can only be 12 inches! (that is SUPER short!)
A number of folks around here have done it, and it probably is not likely to cause an issue if installed and configured correctly, but I just don't see the point. Hard wired allows for more amperage on the same wire in some cases (like mine - I was able to do a 60a circuit on #6 AWG vs. only 50a on a 14-50 receptacle).
Approaching a year of ownership and I had one time where my 14-30 outlet let me down on charging speed.
Was on vacation few hours from home when I got a call my Dad was having a medical emergency. Now he lives 5 hours away but ambulance was transferring him to a hospital 45 minutes from home.
Ended up making 2 stops at a supercharger 30minutes from home one that night and another the next morning because Mom and I didn't spend much time at home the first night for the car to charge.
All worked out well Dad is better than he was before the incident but had I had a higher amperage charging solution even just the 48amp like newer cars have I would have been able to skip the supercharger stops. Just once in a year, but when I needed it the $200 cost difference wouldn't have bothered me a bit.
Was on vacation few hours from home when I got a call my Dad was having a medical emergency. Now he lives 5 hours away but ambulance was transferring him to a hospital 45 minutes from home.
Ended up making 2 stops at a supercharger 30minutes from home one that night and another the next morning because Mom and I didn't spend much time at home the first night for the car to charge.
All worked out well Dad is better than he was before the incident but had I had a higher amperage charging solution even just the 48amp like newer cars have I would have been able to skip the supercharger stops. Just once in a year, but when I needed it the $200 cost difference wouldn't have bothered me a bit.
Last edited:
I have a Tesla wall connector (technically, they aren't called HPWCs anymore) installed outdoors, and it has worked well for 2 years or so. I recommend that. But in the interests of the discussion -- One small potential disadvantage of using the Wall Connector is the difficulty of returning it if it ever needs service -- you would need to get it uninstalled and then (presumably) reinstalled once repaired. Much easier and cheaper to replace an outlet. And if a UMC needs service, you would not need to uninstall it, just ship it.
The comment about being sure not to allow snow to accumulate in the connector applies regardless of which device you use but is more likely an issue if you leave the cable (WC or UMC) outdoors between charges.
The comment about being sure not to allow snow to accumulate in the connector applies regardless of which device you use but is more likely an issue if you leave the cable (WC or UMC) outdoors between charges.
Another benefit of HPWC - it includes a storage socket on the side that shields the connector from rain & snow.
Got benefit from higher Amp charging last night after returning from a Philadelphia-DC-Philadelpia day trip. Left home with S100D at 100%. 16% when we pulled into the driveway last night. Handful of short trips around DC in hot weather, 10% from SuperCharger during rest stop on return trip.
Normally recharge at 24 - 32 Amps overnight, that wouldn’t get the battery to 80% before my wife would use it this morning. Dialed up to 52 Amps and met the deadline.
Yes, but, the cable is not a tight fit and it is possible for snow to get into the socket and the end of the cable. --
One day last winter, we had high winds and light, powdery snow. Apparently, snow did get blown up into the storage socket on the side of the HPWC while I was out and about. When I tried to plug the cable into the car's charging socket, I could not get it to seat, and it would not latch or charge. I had not looked at the business end of the cable before plugging it in, but when I did so now, I was surprised to see snow packed tightly into the spaces between the connectors and down in the connectors themselves. When you pack snow hard enough, as I did when trying to seat the cable into the connector, it turns to ice. Long story short, I ended up having to melt the ice before I could successfully plug the cable into the car. I pulled the cable into the car and used the car's heating system to melt the ice. (I posted this story here on TMC at the time).
This was the only time I had such an incident in 3 winters, but it is good to be aware of the possibility in case something similar happens to one of you!
Lots of good info in this thread, thanks to everyone. I think what has me leaning toward the HPWC the most is that I hadn’t realized how bad it is to unplug the mobile connector daily. My driveway is right next to my neighbor’s house and I could totally see his kids getting into the UMC if I had to leave it plugged in daily.
Only other concern is that we probably will sell our house within 2 years. I am in an east coast university town, so I could see EV charging being a nice selling point on the house, but not so many Teslas out here. I guess I could just have an electrician remove the HPWC and put a plug in a box instead.
Only other concern is that we probably will sell our house within 2 years. I am in an east coast university town, so I could see EV charging being a nice selling point on the house, but not so many Teslas out here. I guess I could just have an electrician remove the HPWC and put a plug in a box instead.
Or, you could purchase a third-party EVSE (electric vehcile supply equipment, the technical name for the Tesla Wall Connector and similar devices) from someone like ChargePoint or Bosch or ClipperCreek. These provide almost all the advantages of the Tesla unit and can be used by any EV, not only your Tesla. So, you could leave that in place as a selling point, or take it with you if you prefer. They can be had with various charging capacities (rates). The one additional downside to using one is that you would need to use your level 2 adapter with it. But you could leave that attached to the EVSE cable, and save some of the minor inconvenience of attaching and detaching it.
For a HPWC, you use #3 wire with a 100A breaker. The NEMA 14-50 outlet only requires 6/3 wire and a 50A breaker.
The other brands of EVSE cost more and are capable of delivering less, the Tesla unit is good enough there are adapters for other cars to use the Tesla unit. Right now those adapters are not cheap but prices will come down. I see no "value" is spending more for a slower unit today just to maybe have it be easier for the next homeowner to use.
The only advantages I see with other units is some localities have cost sharing programs for a specific brand, reduced rates if you let them have access to the charger info and potentially have some control of it, or if you want detailed energy use data, Tesla doesn't do those things. As a connector though the Tesla is higher capacity and generally a bit cheaper.
barcagp, the Tesla unit is hard wired and if you give it larger wire and breaker capable of much greater charging speeds up to 72amp if your car can receive that much, 48amp if you have the standard charger option so that is 50% faster charge than the 2nd gen UMC or 20% faster than the 1st gen. If you wire it into wire rated for a 14-50 outlet you can dial it down to 40amp which is still 25% better than the UMC 2nd gen at 32amps.
I have gotten by the last 11+ months on the UMC in a 14-30 outlet, worked fine but the UMC plug has been getting warm and cleaning it(not Tesla endorsed) has only helped some, have some concern it is exhibiting wear so a new HPWC is arriving today. This also gives me two options for charging should one fail.
I am going to thumbs down joshk6656 post above not because it is wrong but because it is incomplete in a way that will mislead people into thinking the HPWC is harder to install. The HPWC can be installed with a variety of wire sizes and breaker sizes up to the size he listed but it does not need 3 gauge, can be configured to use anything from 14gauge at 12 amps to the car all the way up to 3gauge and 80 amps to the car. There are 13 setting for how much power it can put out, not just the biggest.
After a little more reading 6 gauge "romex" bundled wire where it is all grouped in a single outer sleeve is good for 55amp which the 80% rule would leave you with the 40amp HPWC setting, but if you have conduit and THHN copper wire(separate wires) depending on the insulation temp rating on 6gauge it would be good for 60 or 75amps allowing you to use 48 or 56amp setting available on the HPWC.
Even is the electrician used 8 gauge copper THHN that is good for 50amps and 40amps from a HPWC.
The only advantages I see with other units is some localities have cost sharing programs for a specific brand, reduced rates if you let them have access to the charger info and potentially have some control of it, or if you want detailed energy use data, Tesla doesn't do those things. As a connector though the Tesla is higher capacity and generally a bit cheaper.
barcagp, the Tesla unit is hard wired and if you give it larger wire and breaker capable of much greater charging speeds up to 72amp if your car can receive that much, 48amp if you have the standard charger option so that is 50% faster charge than the 2nd gen UMC or 20% faster than the 1st gen. If you wire it into wire rated for a 14-50 outlet you can dial it down to 40amp which is still 25% better than the UMC 2nd gen at 32amps.
I have gotten by the last 11+ months on the UMC in a 14-30 outlet, worked fine but the UMC plug has been getting warm and cleaning it(not Tesla endorsed) has only helped some, have some concern it is exhibiting wear so a new HPWC is arriving today. This also gives me two options for charging should one fail.
I am going to thumbs down joshk6656 post above not because it is wrong but because it is incomplete in a way that will mislead people into thinking the HPWC is harder to install. The HPWC can be installed with a variety of wire sizes and breaker sizes up to the size he listed but it does not need 3 gauge, can be configured to use anything from 14gauge at 12 amps to the car all the way up to 3gauge and 80 amps to the car. There are 13 setting for how much power it can put out, not just the biggest.
After a little more reading 6 gauge "romex" bundled wire where it is all grouped in a single outer sleeve is good for 55amp which the 80% rule would leave you with the 40amp HPWC setting, but if you have conduit and THHN copper wire(separate wires) depending on the insulation temp rating on 6gauge it would be good for 60 or 75amps allowing you to use 48 or 56amp setting available on the HPWC.
Even is the electrician used 8 gauge copper THHN that is good for 50amps and 40amps from a HPWC.
Last edited:
I had the same dilemma and went down both paths, initially deciding on a NEMA 14-50 for outdoors. My car is parked in my backyard which is completely exposed to the weather, so the electrician installed it in a weather proof enclosure. 3 weeks before taking delivery of my Model 3, after reading a bunch of stuff about ease of use in the rain and having doubts on the weather proof enclosure because it was really small, I ultimately decided to backtrack and ordered the HPWC. When it arrived, I called the electrician back and he was able to install the HPWC at the same location by removing the NEMA outlet and running the wires into the HPWC. I've since left it plugged in in some pretty heavy rain storms and no problems so far. So just wanted to share about the extra peace of mind, and the decision is reversible if you decide against it later, granted your wiring supports it. I had gauge 6 wiring on a 40 amp breaker for mine.
Similar threads
- Question
