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A cautionary tale of a NEMA 14-50 installation

wraithnot

Model 3 VIN #2942 Model S VIN #5785
Dec 16, 2012
569
408
SF Bay Area
I picked up my car at the factory on Saturday and had the electrician come over to install my NEMA 14-50 outlet bright and early this morning. After about an hour, he was finished and the install looked nice an clean. I wrote him a check, he went on his way, and I quickly plugged the charger in. I figured I would add a few miles of range before it was time to head off to work since the 120 V 12A overnight charge wasn't able to completely replace the charge used up by the weekend joyriding. As I was getting ready to go to work, I smelled something that smelled like burning plastic. I went over to the breaker box where the new breaker for the 14-50 was installed and I noticed some thin wisps of smoke coming out around the new breaker!:scared:

I yanked the charge cord out of the wall, shut off the breaker and quickly called the electrician back. He was properly concerned and raced back to investigate. Both the new breaker and the adjacent existing breaker had obvious burn marks. He drove back to the shop, got two new breakers, cleaned the bus bar, replaced both breakers, and then I plugged the charger back in and he waited there about 10 minutes to make sure everything was OK. After giving me the all clear, he went on his way again and I went to work. When I got home, I plugged back in and the car is now happily charging with no further incidents.

I'm still not sure if the new breaker was defective or just the act of messing around with the original 1954 electrical system in our house caused something else to fail. If you already have your car when you get your plug installed, I would strongly suggest having the electrician hang around for five or ten minutes while it's charging just to make sure nothing is out of the ordinary. If you get your plug installed before you get your car, you might want to hang around for a few minutes the first time you charge it. It would be a real shame to burn down your house- and your brand new Model S!
 
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Reactions: TaoJones

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
Just curious - what type of panel do you have?

I've seen some cheaper breakers have loose-ish clips that don't hold to the bus bar well. It could also be that the breaker wasn't snapped all the way on, and the panel cover was the only thing holding it against the bus bar. Good that you detected it before something greater happened.

When things go well, it doesn't seem like all that much of a load... but 40A is significant and an HPWC is bigger than some subpanels!
 
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Reactions: TaoJones

wraithnot

Model 3 VIN #2942 Model S VIN #5785
Dec 16, 2012
569
408
SF Bay Area
Just curious - what type of panel do you have?

I've seen some cheaper breakers have loose-ish clips that don't hold to the bus bar well. It could also be that the breaker wasn't snapped all the way on, and the panel cover was the only thing holding it against the bus bar. Good that you detected it before something greater happened.

When things go well, it doesn't seem like all that much of a load... but 40A is significant and an HPWC is bigger than some subpanels!

I'm not an electrician so I don't know the proper terminology to describe the panel. But I do have an iPhone. Here is a photo of the box and of the breakers. New breaker is on the bottom and existing is on the top.
breaker_box.JPG
breakers.jpg
 

yobigd20

Well-Known Member
Oct 28, 2012
5,929
531
Skaneateles, NY
yea, and double check all the smoke detectors in your house and make sure the batteries are working. you should be doing that frequently anyway. for me, my kid's rooms are directly above the breaker box on the opposite side of the house, so it's critical for me to always know they are functioning.
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
I'm not an electrician so I don't know the proper terminology to describe the panel. But I do have an iPhone. Here is a photo of the box and of the breakers. New breaker is on the bottom and existing is on the top.

Looks like a Siemens QT panel.

EDIT: Now that I look closer, that new breaker's clip looks like it has spread quite a bit. It's likely that it wasn't fully contacting the buss - it might have gotten bent when snapping it on, there may have been a coating on the buss, etc. Too hard to tell following failure, other than to know it wasn't a good connection. Good thing you found it.

- - - Updated - - -

If that box is a Federal Pacific (from a glance it could be), you should replace the whole panel. Have your electrician check it out.

-- Edit --
Check your panel on http://www.ismypanelsafe.com

His panel is not.

FPE Stab-lok are pretty easy to identify - they typically have orange bars on the end of the breakers, with the numbers in black... note I say "typically". Look for the word "Stab-lok" anywhere on the door, "Federal-Pacific Electric" on the front of the panel door, or the tell-tale orange bars:

FPENoTripCramerM.jpg


- - - Updated - - -

I have a federal pacific box and my electrician didn't know anything about this. He thinks i am fine. Should i be concerned?

Yes!

FPE panels are well-known for failures, and in some failure cases 80% of breakers will fail to trip!

The FPE panels in and of themselves aren't a fire-starter (unlike Zinsco panels), but they don't provide adequate protection against a failure. In my case, about 15 years ago, I had a failure of a wiring splice in the wall, which lead to the splice turning into a low-current heating element; once the insulation melted out of the way, the wires created a near-dead-short, allowing many, many more amps to flow. This would normally cause a breaker to trip -- but unfortunately, my FPE breaker jammed and failed to trip. This caused a runaway current flow in which the whole length of the circuit heated up, melted the insulation, and nearly burned down my home. Another 10-20 minutes and I'd likely have faced a total loss - had I not been home, certainly it would have burned.

The biggest problem is that there is no way to know whether you're going to experience a failure or not. Many FPE breakers will trip the very first time they experience an overcurrent problem, and then never trip again (because they are jammed). To have full faith in your panel would require removing the breakers, testing them several times on special equipment, inspecting the panel, then reinstalling them all -- and even then my confidence level would only be 80-90%.

My personal view - if you have a Zinsco/Sylvania-Zinsco or FPE panel, I would replace it. I would certainly not charge my Tesla through it, without some kind of supplemental overcurrent protection device (another subpanel, or a properly-rated disconnect).
 
Last edited:

Morristhecat

Member
Jul 3, 2012
724
204
Burnaby, BC
Thanks flasherz. You flagged this just in time for me. I'm getting a new electrician... I'll get a panel upgrade.

A quick google search confims what you are saying with a gluttony of warnings. Oh well..
 

wraithnot

Model 3 VIN #2942 Model S VIN #5785
Dec 16, 2012
569
408
SF Bay Area
Looks like a Siemens QT panel.

EDIT: Now that I look closer, that new breaker's clip looks like it has spread quite a bit. It's likely that it wasn't fully contacting the buss - it might have gotten bent when snapping it on, there may have been a coating on the buss, etc. Too hard to tell following failure, other than to know it wasn't a good connection. Good thing you found it.

@FlasherZ Wow- you really know your electric panels! I checked the panel after reading ddenboer's comment and all the breakers are labelled "I-T-E" which google says has at least some relation to Siemens.

@Kaivball- the last house I lived in had old-school fuses so actual circuit breakers are a step up :)

@youbigd20-great point about installing a smoke detector in the garage. We have working smoke detectors in the living area, but none in the garage. Perhaps a trip to home depot is in order.
 

Puyallup Bill

Member
Sep 7, 2012
605
2
Puyallup WA
@youbigd20-great point about installing a smoke detector in the garage. We have working smoke detectors in the living area, but none in the garage. Perhaps a trip to home depot is in order.
I have inter-connected smoke alarms in the living area, that is, if one sounds, they all sound. But, I rent, so access to the inter-connection wiring is not available to me.

I ended up with a pair of wireless First Alert Onelink alarms. One in the garage, one in the living area. If the garage alarm sounds, so does the one in the house.
 

FlasherZ

Sig Model S + Sig Model X + Model 3 Resv
Jun 21, 2012
7,024
1,013
@FlasherZ Wow- you really know your electric panels! I checked the panel after reading ddenboer's comment and all the breakers are labelled "I-T-E" which google says has at least some relation to Siemens.

To be fair, I spoke a bit incorrectly - it's a Siemens QT breaker, not panel. Panels labeled Siemens EQ, Siemens Ultimate, ITE, and Gould will hold those breakers if rated for quad breakers. I-T-E was bought by Gould, which was bought by Siemens.

When adding breakers to panels, always be sure the panel is rated to handle the breaker you're putting in it. The label will list approved breakers (if you have one).
 

neroden

Model S Owner and Frustrated Tesla Fan
Apr 25, 2011
14,676
62,627
Ithaca, NY, USA
I've seen that happen when the wires were not terminated or tightened properly at the breaker.

My electrician told me that proper wire termination at the breaker box was absolutely crucial. While he was carefully tightening the neutrals and grounds. :)

- - - Updated - - -

@Kaivball- the last house I lived in had old-school fuses so actual circuit breakers are a step up :)

FWIW, if you know what you're doing, fuses are a lot more reliable than circuit breakers. The reason they went out of fashion is that so many people *don't* know what they're doing with fuses. There's a special tool for pulling bar fuses, for instance: wooden pliers. Did you know?

I grew up in a house with *beautiful* panels from the 1920s. Polished brass, with varnished wood mounting. Bar fuses in pairs of brass clips. Double knife switches (wood & brass) on each circuit. We replaced them with a circuit-breaker panel when we upgraded the electrical system -- partly to make the house more saleable, because the exposed electrical current scares current purchasers. (It's perfectly safe as long as you don't stick your fingers in it!) The electricians walked off with the panels. I hope they didn't go in a dumpster; I suspect, given the admiration that the electricians had for the 1920s workmanship, that they're on some electrician's mantlepiece. I wish I had pictures.
 

wraithnot

Model 3 VIN #2942 Model S VIN #5785
Dec 16, 2012
569
408
SF Bay Area
My electrician told me that proper wire termination at the breaker box was absolutely crucial. While he was carefully tightening the neutrals and grounds. :)

- - - Updated - - -



FWIW, if you know what you're doing, fuses are a lot more reliable than circuit breakers. The reason they went out of fashion is that so many people *don't* know what they're doing with fuses. There's a special tool for pulling bar fuses, for instance: wooden pliers. Did you know?

I grew up in a house with *beautiful* panels from the 1920s. Polished brass, with varnished wood mounting. Bar fuses in pairs of brass clips. Double knife switches (wood & brass) on each circuit. We replaced them with a circuit-breaker panel when we upgraded the electrical system -- partly to make the house more saleable, because the exposed electrical current scares current purchasers. (It's perfectly safe as long as you don't stick your fingers in it!) The electricians walked off with the panels. I hope they didn't go in a dumpster; I suspect, given the admiration that the electricians had for the 1920s workmanship, that they're on some electrician's mantlepiece. I wish I had pictures.

Believe it or not, some people don't even get the concept of a circuit breaker. A family friend got confused when her Christmas Lights weren't working so she found the breaker box and manually HELD the breaker in the on position to get the lights working again. If I remember the story correctly, she let go when things starting smoking. My dad had to go over and help her out by replacing the fried circuit breaker and explaining its purpose.

The panel you described sounds like some sort of steam punk / victorian work of art. The fuse box in our previous rental home was a small dirty metal box on the exterior of the house.

As for my NEMA 14-50 install, the car has been happily charging every night for the past two weeks with no further incidents. But I did install a smoke detector in the garage directly above the breaker box for some extra peace of mind.
 

aaronw

Member
Dec 19, 2012
292
0
United States
Research Federal Pacific boxes. You should definitely be concerned and replace it. They do not meet UL specifications and have an extremely high failure rate. The same goes for Zinsco boxes.
 

LaRamVan

New Member
Apr 19, 2016
1
0
Florida
I picked up my car at the factory on Saturday and had the electrician come over to install my NEMA 14-50 outlet bright and early this morning. After about an hour, he was finished and the install looked nice an clean. I wrote him a check, he went on his way, and I quickly plugged the charger in. I figured I would add a few miles of range before it was time to head off to work since the 120 V 12A overnight charge wasn't able to completely replace the charge used up by the weekend joyriding. As I was getting ready to go to work, I smelled something that smelled like burning plastic. I went over to the breaker box where the new breaker for the 14-50 was installed and I noticed some thin wisps of smoke coming out around the new breaker!:scared:

I yanked the charge cord out of the wall, shut off the breaker and quickly called the electrician back. He was properly concerned and raced back to investigate. Both the new breaker and the adjacent existing breaker had obvious burn marks. He drove back to the shop, got two new breakers, cleaned the bus bar, replaced both breakers, and then I plugged the charger back in and he waited there about 10 minutes to make sure everything was OK. After giving me the all clear, he went on his way again and I went to work. When I got home, I plugged back in and the car is now happily charging with no further incidents.

I'm still not sure if the new breaker was defective or just the act of messing around with the original 1954 electrical system in our house caused something else to fail. If you already have your car when you get your plug installed, I would strongly suggest having the electrician hang around for five or ten minutes while it's charging just to make sure nothing is out of the ordinary. If you get your plug installed before you get your car, you might want to hang around for a few minutes the first time you charge it. It would be a real shame to burn down your house- and your brand new Model S!

Dear wraithnot, New to forum and 40 years of electrical experience. I hope by now you have replaced your panel with a copper busbar type. I recognize from your photo an ITE panel probably with failing aluminum busbar and possibly too many circuits. "Clean" the busbar is a bandaid repair and most likely will return overheating problem.
Before we install a charger circuit, we perform a load calculation to discover if there is enough ampacity headroom for added load. This, along with electrical permits covers any liability and I have had cases where the service size would not accommodate 40 amp added load.
Thanks.
 

HotAir

Member
Feb 13, 2016
18
3
Louisville, KY
When it was time to add our charging circuit last month, we found out that our circa 1980's panel needed replacing. Although it was up to code when installed, the panel was no longer UL rated, and our electrician recommended replacement. It cost a few extra $$ but knowing it is safe is worth the extra cost now.
 

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