FIRE using LVL 1 - 120 V Trickle Charger

[jdunmyer]

For residential circuits, I'm afraid it's very usual. In my brand new house, only the kitchen circuits and some of the lighting are 20a 12ga. The rest are 15a and 14ga. If I could have upgraded (and if I'd realized before they wired it) I would have upgraded them.

Yeah, I looked at that Leviton link and saw that the "stab-in" receptacles are wired with 14 gauge wire. I don't think I've ever wired a receptacle with #14.

should I report this to Nissan?

Yeah, if they get enough reports, they'll cripple the EVSEs like Chevy did, limiting them to 8 amps instead of 12.
[/sarcasm]

 

[MikeD]

ste4en: You wrote "Looking at the 2*4 which burnt out it it is worse in two places, as if in the location of where the staples/clips that electricians use to hold the wire along the studs.". One of the causes of house fires is improperly applied cable staples, particularly a staple that was nailed down too tightly on its cable and pinches/cuts through the insulation to the copper wire. This can cause electrical arcing after further insulation degradation over time which can generate a lot of heat but not necessarily trip the breaker at all or not trip it quickly enough to prevent a fire. This is the point of AFCI (Arc Fault Circuit Interrupter) circuit breakers or receptacles, i.e. to detect the arcing quickly enough to prevent a fire. Although the latest NEC codes require them in bedrooms, etc in new home construction they unfortunately have not been perfected from what I hear (they are prone to nuisance tripping and are supposed to be checked monthly) and they are pretty expensive as well if you have a lot of circuits. I expect they will become more common over time, especially if they develop receptacle AFCIs like they have receptacle GFCIs -- but a problem is only an AFCI circuit breaker can protect the wire between the breaker and the first receptacle (and catch a staple problem there, for example).

One other comment: the heat from the fire would be expected to be conducted through the copper wire, so it is quite possible the receptacle/plug melted because of the fire and not because of a defect at the receptacle.

 

[TimLee]

ste4en: You wrote "Looking at the 2*4 which burnt out it it is worse in two places, as if in the location of where the staples/clips that electricians use to hold the wire along the studs.". One of the causes of house fires is improperly applied cable staples, particularly a staple that was nailed down too tightly on its cable and pinches/cuts through the insulation to the copper wire. This can cause electrical arcing after further insulation degradation over time which can generate a lot of heat but not necessarily trip the breaker at all or not trip it quickly enough to prevent a fire. This is the point of AFCI (Arc Fault Circuit Interrupter) circuit breakers or receptacles, i.e. to detect the arcing quickly enough to prevent a fire. Although the latest NEC codes require them in bedrooms, etc in new home construction they unfortunately have not been perfected from what I hear (they are prone to nuisance tripping and are supposed to be checked monthly) and they are pretty expensive as well if you have a lot of circuits. I expect they will become more common over time, especially if they develop receptacle AFCIs like they have receptacle GFCIs -- but a problem is only an AFCI circuit breaker can protect the wire between the breaker and the first receptacle (and catch a staple problem there, for example).

One other comment: the heat from the fire would be expected to be conducted through the copper wire, so it is quite possible the receptacle/plug melted because of the fire and not because of a defect at the receptacle.

I agree with you completely, MikeD.
I had the same thought about staple damage to the cable when I saw the statement about the scorching on the 2X4s.
Definitely rises to the most probable cause on the root cause analysis table.
It only takes a small error to create a fire hazard.
Especially if you load up a 14g wire circuit to 80% of its rated load on a frequent basis.

 

[Ingineer]

Yes, this is one of the things we have heard often from our customers. We can repair/upgrade your EVSE for no additional charge (standard upgrade fee only) if you'd like to send it in.

This is yet another argument against L1 charging for daily use. There is almost always more loss in existing outlets and wiring found in most homes.

This is also why our upgrades all come with a heavy-duty twist-lock connector, and for 120v L1 charging mode we use a separate and easily replaceable adapter so it can be swapped out quickly if it's ever worn or damaged. In addition, the short cord in the OEM configuration tends to pull the plug out of the outlet somewhat, thus exacerbating the problem. Whereas our longer configuration usually means you can rest the unit on something so it's not dangling from the outlet.

If anyone here is still charging on L1, PLEASE CHECK YOUR OUTLETS!

-Phil

 

[RottenMutt]

My house plugs were wired with the "push connectors" rather then using the screw terminals. i found this out when i noticed a plug starting to melt that didn't have anything plugged into it, a plug (computer) further down the circuit was pulling about 1200 watts (10 amps) and with a rather small resistance in the wiring connection (say one ohm) can produce a lot of heat (R*I^2=1*10^2=100 watts).
When i used the cord that came with the car I was using a plug i had wired in the garage with yellow romex and a 20 amp socket so i didn't have any problems. I wired up my clipper creek charging station with 8 gauge wiring.

 

[cwerdna]

In almost every case of issue like this is is the result of one or many of the following:
A cheap outlet
A worn outlet
An improperly terminated outlet
Loose outlet wires
Bad wire or improper wire size
High-resistance connections
etc, etc.

All the described symptoms point to this issue not an issue with the EVSE or the load of the EVSE.

On this note, there was the case of a PiP owner who had an outlet fire due to aluminum wire at his house: http://www.mynissanleaf.com/viewtopic.php?p=249462" onclick="window.open(this.href);return false;.

 

[DaveEV]

Got any pics of the damaged outlet?

Like, others, I'd put money on a faulty outlet. There's simply nothing to go wrong with the EVSE plug, if there was, the plug would melt down, not the outlet. Good idea to install a smoke detector in your garage.

Especially if you load up a 14g wire circuit to 80% of its rated load on a frequent basis.

In theory, that's why a circuit is rated to 80% of it's rated load for continuous loads such as EV charging, instead of 100%. In practice, of course, poorly installed or worn outlets can lead to issues like this.

 

[adric22]

You said the wiring is 14 gauge. That is unusual, most outlets are wired with 12 gauge, which is rated for 20 amps.

My house was built in the 1990's and every single outlet uses 14 gauge wire and they are terminated through the holes in the back... or rather I should say they were terminated that way. When our heater went out a few years ago we used space heaters in some of the rooms and the outlets melted, mostly in the back where the wires went in. That's when I realized how bad that type of termination is. So I replaced all of the outlets and screwed the wires down on the sides. Never had any problems since. 2 years ago we built 3 extra rooms onto the house. I actually wired them myself and used 12 gauge on all of the plugs and screwed them down. I even ran a dedicated 20-amp outlet for my laser printer. It really stinks that most houses have such inferior wiring jobs.

I installed a 240V EVSE in my garage but I also ran a dedicated 20-amp outlet in case I ever needed to use the portable EVSE. It turns out to have been a good thing since a year later we got a Volt to go along with our Leaf. I've been charging the Volt from its standard 120V unit for the last year and a half from that dedicated 20-amp with no issues.

 

[jdunmyer]

jdunmyer wrote:
You said the wiring is 14 gauge. That is unusual, most outlets are wired with 12 gauge, which is rated for 20 amps.

My house was built in the 1990's and every single outlet uses 14 gauge wire and they are terminated through the holes in the back... or rather I should say they were terminated that way. When our heater went out a few years ago we used space heaters in some of the rooms and the outlets melted, mostly in the back where the wires went in.

Yes, I stand corrected on that. I've been wiring stuff since I was 14, starting with Dad's barn and now doing my new garage, but have never gotten a license. I have been fortunate to work with a couple of very good electricians at the Buckley [Michigan] Old Engine grounds, so have picked up some tips on recent code such as grounding, etc. Although I might have wired some receptacles with #14 long ago, I've never done so recently, and would have (did) guessed that #12 was required by code.

When wiring my shop back in 1968, I was buying my components at Sears and noticed the difference in outlets, some selling for $.79, others for $1.50 or somesuch. It was obvious which were better, so that's what I used. My most recent jobs are using 20-amp rated receptacles. The new garage will also have a dryer-type receptacle next to the Schneider EVSE so I can plug in my upgraded EVSE if the Schneider fails.

To return to the subject at hand, it might be wise of Nissan to add something to the owner's manual about checking the garage outlet that you're using for charging. A simple "feel with your hand for heat" test would be better than nothing.

 

[Nubo]

using a $0.99 13 year old outlet causes fire.

No surprises here.

Every leaf should come with a recommended set of things to buy when you get the car, a 20 amp outlet (which costs under $20 usually) wired up into whatever area you want will fix the trouble

I'd only install a 20A outlet if the circuit wiring and breaker support it. I.e., don't install a 20A outlet if the circuit has 14gauge wiring and/or protected by a 15A breaker. You don't want to mislead a future user into thinking a 20A device (with a sideways prong on the plug) is ok to be used on what is actually a 15A circuit.

 

[MikeD]

ste4en: You wrote "I am not sure if I can repair the trickle cable it is a little melted at the plug but otherwise fine.". I haven't heard from anybody how the 2013 (and presumably 2014) trickle charger monitors its plug for high temperature (wouldn't want to tear into my trickle charger myself if it had this feature), but suspect (hope?) it is a sensor located in the plug itself with perhaps another short wire running to the control box. If this is correct, then replacing the plug may eliminate this useful monitoring feature. If your trickle charger seems to function properly, it may be best to leave the plug as it is. I would expect Nissan to say if asked that altering the trickle charger in any substantive way invalidates its warranty, but can't hurt to see what useful statement they may make about plug being unique and not easily replaceable like plugs for most electrical devices.

 

[RegGuheert]

My house plugs were wired with the "push connectors" rather then using the screw terminals. i found this out when i noticed a plug starting to melt that didn't have anything plugged into it, a plug (computer) further down the circuit was pulling about 1200 watts (10 amps) and with a rather small resistance in the wiring connection (say one ohm) can produce a lot of heat (R*I^2=1*10^2=100 watts).

That is a dangerous code violation, likely done by a previous owner. Outlets should never be daisy-chained by wiring them through the outlet, and doing it with stab connections is particularly dangerous. (The obvious exception is when a single AFCI outlet is used to protect multiple outlets, but even then it should only done at the AFCI outlet itself.) Instead, all wires which are daisy-chained need to be bonded together with with an additional pigtail using a wire nut or another approved technique. This prevents the current for the other outlets from flowing through the upstream outlets. If you haven't done so already, I recommend that you inspect and correct all outlets wired this way in your house.

When i used the cord that came with the car I was using a plug i had wired in the garage with yellow romex and a 20 amp socket so i didn't have any problems. I wired up my clipper creek charging station with 8 gauge wiring.

Yellow Romex is 10AWG. That can sometimes be a challenge to get under the screw terminals on the outlet in some cases unless you drop it down to 12AWG using a wire-nut connection.

 

[wwhitney]

Outlets should never be daisy-chained by wiring them through the outlet

This is not a code violation, and 15 amp receptacles are rated by UL for 20 amp pass through for precisely this reason.

Cheers, Wayne

 

[MikeD]

RegGuheert: We all make mistakes when we post, but I find it helps to try to check myself before I post if I can. I'm sure you meant to say recent (not sure how recent) white, yellow, and orange NM wire is usually 14, 12, and 10 AWG respectively.

I believe your comment about daisy chaining and use of pigtails applies to the ground wire, not the hot or neutral wires, but I haven't the time to check this now.

 

[RegGuheert]

RegGuheert: We all make mistakes when we post, but I find it helps to try to check myself before I post if I can. I'm sure you meant to say recent (not sure how recent) white, yellow, and orange NM wire is usually 14, 12, and 10 AWG respectively.

Thanks for the correction!

I believe your comment about daisy chaining and use of pigtails applies to the ground wire, not the hot or neutral wires, but I haven't the time to check this now.

That would be crazy if code allowed that!

Edit: Regardless of what NEC requires, best practice certainly looks like this:

To minimize the risk of fire, I will again recommend that any daisy-chained outlets (other than correctly-wired AFCI circuits) be changed to look like this. 10X the recommendation if the daisy-chaining was done using stab-type connectors!

 

[TickTock]

Maybe future L1 EVSEs should add built-in smoke detectors/circuit breakers since there are a lot of dodgy 120V outlet installations and the typical homeowner assumes if the plug fits all is well. Could be an interesting stand-alone product, too. A circuit breaker that plugs into a standard outlet and provides a protected outlet that trips if excessive heat or smoke is detected. Like the inline GFI plugs available today but with fire hazard also covered. Could be used for heaters as well as EVSEs.

 

[adric22]

Maybe future L1 EVSEs should add built-in smoke detectors/circuit breakers since there are a lot of dodgy 120V outlet installations and the typical homeowner assumes if the plug fits all is well. Could be an interesting stand-alone product, too. A circuit breaker that plugs into a standard outlet and provides a protected outlet that trips if excessive heat or smoke is detected. Like the inline GFI plugs available today but with fire hazard also covered. Could be used for heaters as well as EVSEs.

Nah... That's a little overboard. I wouldn't mind if the EVSE had a big warning label attached to it suggesting it not be used in an outlet that hasn't been certified for 12 amps continuous power by an electrician, then suggesting it would be a fire hazard to ignore that warning.

 

[RegGuheert]

Maybe future L1 EVSEs should add built-in smoke detectors/circuit breakers since there are a lot of dodgy 120V outlet installations and the typical homeowner assumes if the plug fits all is well. Could be an interesting stand-alone product, too. A circuit breaker that plugs into a standard outlet and provides a protected outlet that trips if excessive heat or smoke is detected. Like the inline GFI plugs available today but with fire hazard also covered. Could be used for heaters as well as EVSEs.

Don't some have thermistors built into the 120V plug to detect if there is too much heating? If not, that would seem like a good idea.

 

[GregH]

Wow! Glad to hear it wasn't a whole lot worse..
I've been nervous the last few weeks running my 120V L1 at 17-18A due to the messed up OBC line voltage detection (I can't charge at 240V).
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.
It got warm but never close to seriously so (and I've inspected the contacts on both sides for any signs of melting). The good news is that after taking the car back to Nissan for the 3rd time they re-confirmed the problem, recorded data, was allowed to order a new charger, received said new charger and it is now being installed. Unfortunately after playing with it for 8 hours yesterday they still don't have the thing installed so I got to commute outside of the carpool lanes again today in an Altima.. I SO look forward to getting my car back with normal charge capability.

 

[RegGuheert]

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.