Leviton introduces new 14-50 receptacle for EV charging

[3sr+buyer]

Good review
Leviton has responded and fixed their products

Actually, they added a high end offering (model 1450R) with improved wire clamping and full size contacts to the plug blades.

But they still offer their low end offering (model 279-S00) that is worse than other low end competitors due to the half size contacts to the plug blades.

 

[Ti317]

To be fair though, the melted plugs are mostly not because they are designed poorly or can't withstand the load. The issue is almost always a poor connection. Either directly the prongs (corroded), or more often the wires are not attached tight enough or became lose. This creates an electric resistance which causes a lot of heat build up. The metal parts and copper wires can handle the heat, but not the plastic parts. They start to melt.

I have done a lot of high power wiring and I always make sure all connections are tight. Then I run a load test and check everything for temperature. I had a few cases where it looked like a good connection but it wasn't. At a friend's place I used a standard 120 outlet to charge. I check the temperature and noticed the outlet got warm. I opened it and tightened all screws holding wires. From thereon the outlet stayed cool.

I was under the impression that overheating was mainly caused by wear of the contacts from frequent unplugging and reconnecting. The explanation I was given was that with repeated use the tension between the prongs of the plug and the contacts inside the receptacle diminishes causing heat at the points of contact.

 

[Rocky_H]

I was under the impression that overheating was mainly caused by wear of the contacts from frequent unplugging and reconnecting. The explanation I was given was that with repeated use the tension between the prongs of the plug and the contacts inside the receptacle diminishes causing heat at the points of contact.

That is one cause, and is what people frequently see in standard really old 120V outlets, but I think it's one of the three main causes. And is perhaps by % of cases, probably not the top one.

1. Loose (or badly done) screwed in wire connections on the back. With the way some outlets are, as the wire is screwed down, strands of the wire get splayed out to the sides, which loses some of that contact area. Or through a couple of years of use, the heating and cooling makes the metal expand and contract, and the screw just isn't holding the wire tightly anymore and needs to be re-tightened.

2. That old model of Leviton outlet had some really pathetic half sized steel plated contacts inside. That made it pretty resistive regardless and always warmer than it needed to be.

3. The firmness of the spring tension you mentioned.

 

[3sr+buyer]

That is one cause, and is what people frequently see in standard really old 120V outlets, but I think it's one of the three main causes. And is perhaps by % of cases, probably not the top one.

1. Loose (or badly done) screwed in wire connections on the back. With the way some outlets are, as the wire is screwed down, strands of the wire get splayed out to the sides, which loses some of that contact area. Or through a couple of years of use, the heating and cooling makes the metal expand and contract, and the screw just isn't holding the wire tightly anymore and needs to be re-tightened.

2. That old model of Leviton outlet had some really pathetic half sized steel plated contacts inside. That made it pretty resistive regardless and always warmer than it needed to be.

3. The firmness of the spring tension you mentioned.

These manifest themselves differently in terms of outlet failure (melting or burning):

1 will see melting or burning at the back of the outlet, and should be brand/model agnostic, except that pressure clamp models like the Hubbell 9450A, Bryant 9450FR, and Leviton 1450R are less likely to have this occur. Careful installation can avoid this issue with screw down models, although the pressure clamp models are more mistake resistant in installation.

2 is specific to the Leviton 279-S00 and will see melting or burning at the front of the outlet. This seems to be a very common type of reported outlet failure. Installation care does not affect this mode of failure.

3 can occur on any outlet that is subject to many plug/unplug cycles, though that seems more likely at RV parks than elsewhere. Outlets with poor contacts when new like the Leviton 279-S00 may need fewer plug/unplug cycles for the contact to fail in this way.

 

[pikeman]

Perhaps they have noticed that their 279-S00 receptacle shows up often in "melted receptacle" posts in various forums and social media?

Leviton Introduces 50A Heavy Duty EV Charging Receptacle

/PRNewswire/ -- Leviton today announced the introduction of its new industrial grade 50 Amp Heavy Duty EV Charging Receptacle. The device is the ideal solution...

www.prnewswire.com

50 Amp EV Charging Receptacle/Outlet, Heavy Duty, 1450R

Designed specifically for plug-in EV charging applications, Designed to sustain the necessary extended charge time and high frequency of insertions EV chargers require. Perfect option for homeowners who prefer a plug-in EV charging units as opposed to a hardwire application Built of durable...

store.leviton.com

But since it costs a lot more than the 279-S00, will most people still grab the 279-S00 at the store?

Only if they are stupid. Stoopid! Electrical items are always best treated by over-speccing the hardware and only buying first-rate gear. A good electrician will always buy the heavy duty high quality components. There are numerous goofball threads on this and they are fires waiting to happen. That’s why a permit is required and a lic electrician should be hired.

 

[kpanda17]

I thought I read in a separate thread that Teslas had an internal GFCI and that installing a GFCI breaker could cause intermittent ‘charging stopped for unknown reason errors?”

"The National Electrical Code (NEC) requires GFCI protection for all outlets in garages that are 50 amps or less and rated not over 150 volts to ground."
Tesla's mobile connector does not have a built-in ground-fault circuit interrupter (GFCI).
if it trips, there is a wiring, breaker problem

 

[stopcrazypp]

"The National Electrical Code (NEC) requires GFCI protection for all outlets in garages that are 50 amps or less and rated not over 150 volts to ground."
Tesla's mobile connector does not have a built-in ground-fault circuit interrupter (GFCI).
if it trips, there is a wiring, breaker problem

The mobile connector does have a GFCI built-in, here is an example of it tripping:

Mobile Connector GFCI Tripped

Hello noob here, I have an issue with my gen 2 mobile connector 4 years in. The car’s screen specifically says “Unable to charge - Mobile Connector GFCI Tripped.” My nema 14-50 isn’t connected to a GFCI breaker. I reconnect the charger and it works like a charm. But everyday I have to...

teslamotorsclub.com

That does not satisfy NEC because that GFCI does nothing to protect the receptacle (someone can still get shocked from the receptacle even after the GFCI in the mobile connector trips).

 

[Rocky_H]

That’s why a permit is required and a lic electrician should be hired.

The thread I literally was just looking at before this was someone dealing with problems where their licensed electrician put in a circuit that was 30A, with 10 gauge wire, but the dumb electrician used a 14-50 outlet instead of the 14-30 it should have had. Yes, it's good, but a licensed electrician isn't a guarantee that it will be right.

 

[kpanda17]

Please question the experience of the licensed electrician with these multi-hour running EV charging circuits.
Even by licensed electricians, I see wrong gauge wire, use of aluminum wire and no skills to fully program the Tesla wall connector, wifi, app, etc.
Get electricians that have experience in setting up home EV charging.

 

[Rocky_H]

Even by licensed electricians, I see wrong gauge wire, use of aluminum wire [...] Get electricians that have experience in setting up home EV charging.

But that's the horrible thing. Those specific errors you mentioned in the first part of your sentence have nothing at all to do with EVs!! Not being able to select the right wire gauge or the right receptacle rating are just basic fundamental things for an electrician's career.

 

[kpanda17]

But that's the horrible thing. Those specific errors you mentioned in the first part of your sentence have nothing at all to do with EVs!! Not being able to select the right wire gauge or the right receptacle rating are just basic fundamental things for an electrician's career.

The NEC code does not tightly address the experiences we have with EV charging at home and the design. Aluminum wiring is code. Six gauge for 48 amps is code. But the best electricians with EV home charging design and install experience only use copper and 4 AWG.
Interview at least two electricians for selection and question them on the number of experiences and ask questions referencing the Tesla Wall Connector install manual for such things as torque lbs, wifi pairing, etc. If you don't hear the right answers, move on and find ones that have the right answers.

 

[Rocky_H]

No, I'm going to address these:

Aluminum wiring is code.

ONLY if it is between devices that are specifically marked to say they will allow connections with aluminum wire!! The aluminum use problem we see sometimes is people putting aluminum directly into wall connectors or receptacles that don't allow it. That is a straight up simple code violation. And that has nothing to do with EV or not. It's just not following equipment manufacturers' instructions. Period. There is no problem with using aluminum wire for part of an EV use circuit if it is done properly. That use would be if someone needs to get 100 feet away from the other end of their house into a subpanel in the garage. Subpanels are usually marked to take either copper or aluminum.

Six gauge for 48 amps is code.

Maybe yes or maybe no. You're overgeneralizing. The answer to this depends entirely on what type of wire it is, and the installation conditions/location. A 60A circuit is a 60A circuit, and it is pretty basic to see if the wire type and gauge has a proper ampacity rating for a 60A circuit. And again, that doesn't have anything to do with whether it's for an EV or not.