FIRE using LVL 1 - 120 V Trickle Charger

[GregH]

It is however fed by a true 14-50 socket on a 40A breaker and the only point between the 14-50 and the L1 EVSE is a 2 inch 120V adapter I cobbled together.

The wiring in the 120V pigtail adapter for the EVSE is only rated for 20A and the rest is only 20A or 30A depending on what version EVSEUgrade you have. I'd recommend putting that outlet on a 20A breaker until your charger is fixed.

Hopefully that is TODAY!!

 

[Valdemar]

Sounds like this is not what happened in this case but I had the stock L1 EVSE plug heating up noticeably on the hot side. Taking it apart and tightening up the terminal screw took care of it. It still gets a bit warm, but not dangerously so.

 

[ste4en]

Here are some pictures.

http://i57.tinypic.com/335eb9e.jpg
http://i57.tinypic.com/sgo8jo.jpg
http://i57.tinypic.com/2s9qazs.jpg
http://i60.tinypic.com/33kvzo3.jpg

Is that charger salvageable?

 

[davewill]

Here are some pictures.

Is that charger salvageable?

Sure looks like it to me. Heck it looks like it would probably still work if you clean up the plug. Trying it should be fairly safe. First just plug it into the wall and see if the lights come out properly, then try the car, watching it carefully for errors or signs of heating.

 

[MikeD]

ste4en: I notice that your trickle charger's plug looks a look different (and larger) than my 2011 trickle charger's plug, which suggests the possibility that it is more than just a plug as mentioned before.

What happened to the receptacle/outlet box? Was it plastic and pretty much melted/burned away along with a lot of the wiring insulation? Is a professional fire assessor going to be examining this for your insurance company?

 

[Valdemar]

Looks like they switched to a molded plug at some point, probably for safety/reliability reasons. My 2011 charger has a 20A Leviton plug that can be taken apart.

 

[dhanson865]

Here are some pictures.

http://i57.tinypic.com/335eb9e.jpg
http://i57.tinypic.com/sgo8jo.jpg
http://i57.tinypic.com/2s9qazs.jpg
http://i60.tinypic.com/33kvzo3.jpg

Is that charger salvageable?

some web filters block that when you use the URL tag instead of the IMG tag (I had to use the img tag to see it on this pc)

 

[jlatl]

This thread has talked a lot about the plug and receptacle and I agree with all the warnings about making sure your outlet uses good receptacles, they are not worn, screw terminals not push in, etc. (thought: there should be a post at the very top of this forum titled "Red this all new owners - things you should know")

However, I also find the pictures of the burned out studs disturbing. It looks like the problem was not at the outlet but in the wiring in the walls.

Even though you say you had 14ga wire and not 12ga, I cannot believe there is any way that wire should have started burning like that. Warm yes. Even so warm that it would have damaged the insulation over time. But catch fire? There is something more going on here.

One of the posts mentioned that sometimes staples are put in overly tight and this can pinch the wire and damage it. Could be, but whatever the reason there is something scary going on here.

What if you plug in a space heater in another room and that wire has a similar problem. How long would the heater have to run before it caused a similar problem? I know the EVSE chargers have a continuous draw for durations longer than the typical space heater, but .....

I invite others to weigh in, but I would suggest you talk to a good electrician and have your wiring inspected.

On another note, I have sworn off 15A outlets and every outlet I replace or install is rated at 20A. The circuit may still have a 15A breaker, but I just feel more comfortable with the better outlet.

 

[davewill]

... On another note, I have sworn off 15A outlets and every outlet I replace or install is rated at 20A. The circuit may still have a 15A breaker, but I just feel more comfortable with the better outlet.

So long as they don't have the horizontal slot that might let someone plug a 20a appliance into a 15a circuit. I agree about having a professional inspect his wiring. It may not be isolated to this one location.

 

[MikeD]

ste4en: One observation of your third photo is the three sets of wire bundles parallel with the stud seem to be composed of only two wires each, i.e. there doesn't seem to be a third ground wire (only a hot and neutral). On the other hand, the one cable running parallel to the floor does seem to have three wires. If that is correct, I think it is a code violation to connect a pigtail from the neutral to the ground terminal of a three wire receptacle. On the other hand, I can't see how this might have caused a fire -- I think the "equipment ground" is mainly to prevent certain shock hazard situations (like a loose hot wire contacting the metal exterior of an appliance).

One other observation is that the staple securing the vertical cable in that same photo appears it might be pressing against the edge of that cable and not the flat part of it (not good if so). In any case right above that staple the cable's two wires seem to be twisted -- and that definitely seems abnormal. I'm no expert, but that photo makes me think the fire may have originated from that cable and not the two that appear to be used in the receptacle.

 

[DaveEV]

Here are some pictures.

Thanks. In my totally unprofessional opinion:

1. EVSE was not at fault. Only minimal heating evident there.
2. Fire appears to have originated at the outlet given the significant burning of the 2x4 where the outlet would have been.
3. Looking at what remains of the wires, the wires were inserted using the back-stab connectors and not screwed down.
4. Outlet was mounted in a plastic box, not a metal one.

Conclusions:

1. Don't use plastic boxes for outlet boxes.
2. Always use high quality screw down lugs for wires connections.
3. Use a dedicated 20A circuit if at all possible for L1 charging.
4. Install a smoke detector in the garage.

 

[cwerdna]

Looks like they switched to a molded plug at some point, probably for safety/reliability reasons.

Yes, the L1 EVSE that came w/my Leaf has a plug that looks just like the one pictured.

From the sheet (IIRC) that came w/the EVSE, there supposedly is thermal monitoring in the plug, as there is some light pattern indicating the plug overheated.

 

[Valdemar]

^^^ Given there is usually several outlets and possibly junction boxes all of which are potential failure points along the current path from the MSP to the EVSE plug this thermal monitoring is probably there just to protect Nissan from lawsuits. I also wonder why the heat from the melting outlet didn't interrupt charging in this particular case as this incident is exactly what the feature should have helped to avoid.

 

[RegGuheert]

I also wonder why the heat from the melting outlet didn't interrupt charging in this particular case as this incident is exactly what the feature should have helped to avoid.

It may have. I don't think we know what the EVSE did during this episode.

But even if it did eventually interrupt the charging, it did it too late. Perhaps the heat from the wiring was simply too far from the plug to trip it before the problem got out of hand.

I like the right-angle connector on that EVSE, BTW. Still, as others have said, I have come to feel that L1 charging is a bit risky, even with good wiring, due to the plug type, so I try to stick with L2. I find it interesting that the new portable L2 charger advertised recently here uses a similar plug type. I must say that I find Phil's choice of twist-lock plugs to be much more attractive.

 

[cwerdna]

Unfortunately, w/the new plug design, I can't seem to get it to plug directly into the 120 volt outlet under the metal doors of the CT2100 series EVSEs (http://web.archive.org/web/20130403092428/http://chargepoint.com/products-chargepoint-stations.php" onclick="window.open(this.href);return false. We have some of those at work.

If I want to use those, I have no choice but to use an extension cord. I actually don't generally bother w/that anymore. I just defer my @ work charging until late in the day and use L2, instead of typing up a space all day charging @ 120 volts.

 

[Ingineer]

Here are some pictures.

http://i57.tinypic.com/335eb9e.jpg
http://i57.tinypic.com/sgo8jo.jpg
http://i57.tinypic.com/2s9qazs.jpg
http://i60.tinypic.com/33kvzo3.jpg

Is that charger salvageable?

Looks like discoloration on the plug blades. This likely means you could end up with appreciable extra resistance, so I advise that you do not use it until a qualified engineer or electrician examines it.

We can repair and/or upgrade it for you. Just give us a shout an'd we'll be happy to explain the options. Many people here use our products daily.

-Phil

 

[MikeD]

Can we get agreement on any of the following?:
1) the fire must have been caused by an arc fault in order to generate enough heat to cause it
2) the ideal shock/fire protection would have been if the circuits had AFCI circuit breaker protection together with GFCI receptacle protection
3) the receptacle cables should all have equipment ground wires
4) the use of metal rather than plastic outlet box would at the very least made it easier to determine if the fire started inside or outside it and at best might have contained it if the fire had started inside it

 

[RegGuheert]

Can we get agreement on any of the following?:
1) the fire must have been caused by an arc fault in order to generate enough heat to cause it

Disagree. Sufficient heat can result simply from the high resistance associated with the stab-in connections. (I have always questioned the NEC's decision to allow such connections.)

2) the ideal shock/fire protection would have been if the circuits had AFCI circuit breaker protection together with GFCI receptacle protection

Disagree. I doubt AFCI or GFCI would make any difference onion this case.

3) the receptacle cables should all have equipment ground wires

Agree. This has been true for many years.

4) the use of metal rather than plastic outlet box would at the very least made it easier to determine if the fire started inside or outside it and at best might have contained it if the fire had started inside it

Agree. But I'm not convinced metal boxes are "better" in general. There are some fire risks associated with metal boxes that do not exist with plastic ones.

 

[DaveEV]

1) the fire must have been caused by an arc fault in order to generate enough heat to cause it

Most likely.

2) the ideal shock/fire protection would have been if the circuits had AFCI circuit breaker protection together with GFCI receptacle protection

No need for GFCI on the receptacle used only by EVSE, EVSE includes GFCI. AFCI might have helped here.

3) the receptacle cables should all have equipment ground wires

EVSE won't function without it.

4) the use of metal rather than plastic outlet box would at the very least made it easier to determine if the fire started inside or outside it and at best might have contained it if the fire had started inside it

Quite possible.

 

[Ingineer]

I don't usually see MikeD because I have him ignored in my settings for trollish behavior, but this is an interesting point.

I did extensive lab work on EVSE designs with built-in AFCI and sag detection algorithms. My experiments showed that you would have an unacceptably high incidence of nuisance trips with various sag detection algorithms, and as Reg pointed out, AFCI alone is not adequate to stop most of these occurrences, though is does help occasionally.

For instance, the most common scenarios I've seen are simply high resistance at a single point, (or sometime multiple points) that over time, oxidizes and gets worse. Sometimes in only a few hours, and sometimes it may take weeks.

Then, once the resistance gets high enough, the thermal energy released is sufficient to cause ignition of many materials, thus triggering your catastrophic situation.

The "stab-lok" and other types of spring contact rear-wired outlets a particularly bad, as not only are the electrical connections relatively poor, but they also don't help conduct heat away as well from the (usually) worn contacts inside the outlet, thus exacerbating the thermal run-away.

If we only have a bad connection adding 100 milliohms, which I found was easily possible, that's over 14 watts of dissipation on a typical level 1 charging session! Depending on the composition of the materials near the fault, that can easily become a fire, and that's only adding a little over 1 volt of sag, so it's very difficult for a software-based sag detection algorithm to spot this and stop the charge session.

With the advent of cheaper pyroelectric devices and possibly even methods of performing active TDR pulse analysis, we may be able to catch some issues, but definitely not all.

The best thing you can do right now to ensure safety is to have a high-quality twist-lock outlet installed on a dedicated circuit and use that for your daily charging.

It's absolutely dangerous to use an existing, usually poor quality and/or worn 120v outlet for daily continuous loads, and it's more inefficient to boot.

For usually less than $600 total cost you can get a dedicated 240v outlet installed AND get your EVSE upgraded. We have a 100% perfect safety record with both generations of the Panasonic-made Nissan EVSE, and thousands of LEAF owners using them every day.

Don't be a cheapskate and put yourself at risk!

-Phil