EV rated circuit breakers

[jaggedben]

Retire

...
if charging is done based on a simple cord equipped with a 1450 plug on one end and a Tesla charging handle on the other end, plugged into a 1450 receptacle, i don't see how the charging rate can be set automatically. ...

The plug adapter on the Tesla EVSE tells it what the rating of the plug is. The 14-50 adapter therefore tells the cable that more current is available than the plug adapters for lower rated receptacles. (The Tesla cable with the built-in box performs the same function as a wall-hung EVSE here).

But again, all this is not to blame for receptacles melting. The circuit breaker should trip to protect the receptacle no matter what load is plugged into it. Melted receptacles is due to either a receptacle not performing to its purported rating, a breaker not tripping when it should, or a wiring error causing excess heat at the receptacle when under acceptable load.

 

[tortuga]

The circuit breaker should trip to protect the receptacle no matter what load is plugged into it. Melted receptacles is due to either a receptacle not performing to its purported rating, a breaker not tripping when it should, or a wiring error causing excess heat at the receptacle when under acceptable load.

I would love to see a real electrician or inspector do a deep dive analysis on one of these melting receptacles. Should be pretty easy to set up a controlled experiment, get someone who has a melted 14-50 and remove and replace with another of the same, this time with torquing screwdriver, set up some temp, voltage and current sensors to a data logger. Even a IR cam.

 

[curt swartz]

I have not read all the the most recent posts but wanted to add. Even when using the 6-50 or 14-50 Tesla adapters the maximum charge rate is 32 amps.

Tesla has offered a cord with a fixed 14-50 plug that will charge at 40 amps but I don't know anyone that has been able to purchase it. Its is always "out of stock"

Like Tortuga mentioned I would like to see data on why the receptacles are failing. Are the supply wires being torqued properly? Is the customer leaving the charge cord plugged in or unplugging and plugging back in everyday?

Leviton's rear wire entry design is horrible in my opinion and I have only used one once Never again!

When I do install large receptacles I form the wires how they will fold/coil into the box. I make the connections then snug the screws. I push the receptacle into the box then pull out just enough to fully torque the screws. If someone just randomly connects the wires then twists the receptacle all around trying to get it into the box the wires will loosen.

 

[hillbilly1]

I have not read all the the most recent posts but wanted to add. Even when using the 6-50 or 14-50 Tesla adapters the maximum charge rate is 32 amps.

Tesla has offered a cord with a fixed 14-50 plug that will charge at 40 amps but I don't know anyone that has been able to purchase it. Its is always "out of stock"

Like Tortuga mentioned I would like to see data on why the receptacles are failing. Are the supply wires being torqued properly? Is the customer leaving the charge cord plugged in or unplugging and plugging back in everyday?

Leviton's rear wire entry design is horrible in my opinion and I have only used one once Never again!

When I do install large receptacles I form the wires how they will fold/coil into the box. I make the connections then snug the screws. I push the receptacle into the box then pull out just enough to fully torque the screws. If someone just randomly connects the wires then twists the receptacle all around trying to get it into the box the wires will loosen.

From the pictures posted, it looks like more contact area on the expensive versions, that is probably the reason.

 

[retirede]

I have not read all the the most recent posts but wanted to add. Even when using the 6-50 or 14-50 Tesla adapters the maximum charge rate is 32 amps.

Tesla has offered a cord with a fixed 14-50 plug that will charge at 40 amps but I don't know anyone that has been able to purchase it. Its is always "out of stock"

Like Tortuga mentioned I would like to see data on why the receptacles are failing. Are the supply wires being torqued properly? Is the customer leaving the charge cord plugged in or unplugging and plugging back in everyday?

Leviton's rear wire entry design is horrible in my opinion and I have only used one once Never again!

When I do install large receptacles I form the wires how they will fold/coil into the box. I make the connections then snug the screws. I push the receptacle into the box then pull out just enough to fully torque the screws. If someone just randomly connects the wires then twists the receptacle all around trying to get it into the box the wires will loosen.

I’ve seen a lot of pictures of failed 14-50s (none in person).

Some look like the heating starts where one of the wires attach. The sub-$10 ones have the screw (with it’s twisting motion) clamping directly on the wire. I suspect they either don’t get torqued properly or the strands deform and loosen as it thermal cycles. Or both. The expensive receptacles have a box saddle for clamping the wires.

Others appear to start melting near the face, likely due to the difference in blade contact area as shown in previous posts.

Tesla is not the only EVSE supplier. There are any number of name-brand, UL listed, 40A units available with a 14-50P including Emporia, ChargePoint, JuiceBox, and others.
There is also unlisted Chinese junk on Amazon.

I’ve also heard reports of 14-50 receptacles failing when the load is only a 32A EVSE.

Note the difference:

 

[jaggedben]

A question this raises is whether the UL testing procedure or standard itself needs to be revisited. I mean, if inadequate receptacle designs are getting listed for higher amps than they are really capable of running continuously for multiple hours day after day...

 

[curt swartz]

A question this raises is whether the UL testing procedure or standard itself needs to be revisited. I mean, if inadequate receptacle designs are getting listed for higher amps than they are really capable of running continuously for multiple hours day after day...

I agree. If these receptacles are being installed properly and failing they should loose their UL listing.

I have not searched for images of failed receptacles but for those that have are they all Leviton? How about Legrand or Eaton that offer similar priced receptacles.

 

[letgomywago]

I agree. If these receptacles are being installed properly and failing they should loose their UL listing.

I have not searched for images of failed receptacles but for those that have are they all Leviton? How about Legrand or Eaton that offer similar priced receptacles.

Eaton is the brand that lowes stocks so that would also help demonstrate if it's just handyman or homeowner installs that are so prone to this because you can count on them not using a torque screwdriver.

 

[David Castor]

I don't have much experience with these particular sizes, but for the standard 15A and 20A receptacles, there is a major difference between Hubbell and all other brands. Hubbell 5262 is vastly superior in quality and much more substantial than everyone else's "5262". In many applications, this difference might not be worth the extra cost, but in situations where there is frequent heavy loading and/or abuse, it can make a difference. Maybe the extra cost is worth it for these EV applications.

 

[retirede]

Eaton is the brand that lowes stocks so that would also help demonstrate if it's just handyman or homeowner installs that are so prone to this because you can count on them not using a torque screwdriver.

Most (>50%) of the reports of receptacle failures I’ve read about on EV forums are reported to have been installed by licensed electricians. Of course, there’s no way to verify that, but I doubt they’re all lying.

 

[letgomywago]

Most (>50%) of the reports of receptacle failures I’ve read about on EV forums are reported to have been installed by licensed electricians. Of course, there’s no way to verify that, but I doubt they’re all lying.

But the homedepot and lowes electrician I feel is less likely to be the ones following the tourqe instructions. I worked for one at one point and I was the only one using one on anything at all. He did borrow my 3/8th wrench once to do a large unipack but the whole concept was foreign to the company.

I'll add I do have accounts at both places but no where near the exclusive nature of this former employer

 

[retirede]

But the homedepot and lowes electrician I feel is less likely to be the ones following the tourqe instructions. I worked for one at one point and I was the only one using one on anything at all. He did borrow my 3/8th wrench once to do a large unipack but the whole concept was foreign to the company.

I'll add I do have accounts at both places but no where near the exclusive nature of this former employer

I’d venture to guess that before the EV craze started taking off, many electricians didn’t keep 14-50s on hand. Maybe they still don’t. It would make sense to get one wherever was most convenient at the time. Could often be a big box store.

 

[hillbilly1]

The old fashioned surface mount receptacles seem to be better built, with lay in wire clamps and full size contact blades. Just not the best choice if subjected to physical damage because of the phenolic or plastic enclosure.

 

[kwired]

X

if it was profitable, they would put in charging stations in the parking lot, and just rent the parking spot.

Googled how many KWhrs to charge a Tesla. Lets assume it won't be totally dead or they wouldn't be pulling up to the charging station, so maybe they will use 30-50 KWhrs. That might be anywhere from $3.50 to $8.00 in energy at typical residential consumer rates depending on cost in the area and exactly how much charge is used. So how much should you charge to plug in there? If not so many ever use it might take a long time just to recover installation costs unless you only have a couple simple 14-50 receptacles located not too far from some existing supply that can handle the additional load. Self servicing equipment, maybe with credit card reader and associated controls to monitor use and such only adds to installation and maintenance costs, and would likely require a data service to process payments and what not as well.

 

[hillbilly1]

Googled how many KWhrs to charge a Tesla. Lets assume it won't be totally dead or they wouldn't be pulling up to the charging station, so maybe they will use 30-50 KWhrs. That might be anywhere from $3.50 to $8.00 in energy at typical residential consumer rates depending on cost in the area and exactly how much charge is used. So how much should you charge to plug in there? If not so many ever use it might take a long time just to recover installation costs unless you only have a couple simple 14-50 receptacles located not too far from some existing supply that can handle the additional load. Self servicing equipment, maybe with credit card reader and associated controls to monitor use and such only adds to installation and maintenance costs, and would likely require a data service to process payments and what not as well.

It’s just like solar, there is a lot of hidden costs of maintenance and repairs.

 

[retirede]

Googled how many KWhrs to charge a Tesla. Lets assume it won't be totally dead or they wouldn't be pulling up to the charging station, so maybe they will use 30-50 KWhrs. That might be anywhere from $3.50 to $8.00 in energy at typical residential consumer rates depending on cost in the area and exactly how much charge is used. So how much should you charge to plug in there? If not so many ever use it might take a long time just to recover installation costs unless you only have a couple simple 14-50 receptacles located not too far from some existing supply that can handle the additional load. Self servicing equipment, maybe with credit card reader and associated controls to monitor use and such only adds to installation and maintenance costs, and would likely require a data service to process payments and what not as well.

Typical paid use public chargers are $0.25 - 0.30 for level 2 and $0.45 - 0.60 for level 3. Some places in California are higher than that during on-peak hours.

Virtually all are owned and operated by a company that does nothing but public charging. They have the systems to handle payments. They usually just rent space from the local business.

 

[letgomywago]

Does anyone know what the various RV boxes use for their receptacles. I've seen those for that use before and the steel plate should hold better than the 2 gang cheap plastic box that alot of these chargers get. Often floating on 2 inch 632s

 

[kwired]

Typical paid use public chargers are $0.25 - 0.30 for level 2 and $0.45 - 0.60 for level 3. Some places in California are higher than that during on-peak hours.

Virtually all are owned and operated by a company that does nothing but public charging. They have the systems to handle payments. They usually just rent space from the local business.

If within a city and it is in use quite a bit of the time it is likely profitable. If at a campsite I doubt it will be used all that much, in the future maybe more use but now not so much. I still don't think it even pays for itself very quickly in that situation. Payment systems and rented spaces costs still count against the bottom line. A company that does noting but public charging maybe does get better pricing on the payment system equipment and maybe data services (particularly internet service) in some cases though. If they have their own data network they will have to run a network of cables/fiber or have wireless network systems to have to install and maintain. Again maybe more profitable in a city but in a remote campground area you possibly putting similar cost into something that only serves a limited number of those charging stations compared to the multiple stations in the city.

 

[hillbilly1]

Does anyone know what the various RV boxes use for their receptacles. I've seen those for that use before and the steel plate should hold better than the 2 gang cheap plastic box that alot of these chargers get. Often floating on 2 inch 632s

I had a customer supply one of those factory “RV” receptacles and enclosure they bought off of Amazon, real bad quality. Terminal screws wouldn’t hold the wires, they would pop out when you tried to put it back into the too small enclosure. Ended up pulling a MidWest one off the truck and installing it. I didn’t want to be responsible for burning up everything in his motor home if the neutral popped out.

 

[kwired]

I had a customer supply one of those factory “RV” receptacles and enclosure they bought off of Amazon, real bad quality. Terminal screws wouldn’t hold the wires, they would pop out when you tried to put it back into the too small enclosure. Ended up pulling a MidWest one off the truck and installing it. I didn’t want to be responsible for burning up everything in his motor home if the neutral popped out.

Midwest tends to put in receptacles that won't interchange with a standard "device box" mounted receptacle, nor will a standard device box receptacle mount in the Midwest box without some modifications. My guess is they outsource those devices but with their own specifications on them?