EatsShootsandLeafs
Posts: 710
Joined: Fri Aug 24, 2012 10:59 am
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Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 6:38 am

I have:

50 amp breaker
60 amp-rated wiring
14-50 socket

I have attached an EVSE to the socket. The EVSE is rated at 40 amp continuous. I charge at either 3.3 kWh on one car, or 6.6 kWh on my Leaf (max charging rate on the 2020 Leaf SV).

Last night I had the Leaf plugged in and it was charging at 27 amps or whatever it does (I remember distinctly walking past and the car was blinking as it charged). However, this morning it had barely charged. Turns out the breaker was thrown. I put it back and now I'm charging my lower-charge car at 3.3 kWh.

Possible failure points:
  • Breaker
  • wire
  • socket
  • evse
  • leaf's charger
As for failure point...It can't be the wire (most likely not). It could be a bad breaker (breaker is a year old and only been in use past two months), but that seems unlikely it would trip at barely over half its rating.

A pro electrician installed the breaker and the wire, but I put the 14-50 socket in two months ago. I'm thinking even if I did a bad job and stressed the cabling on this it would either now be creating a complete short (and an instant breaker throw), or excessive heat or something, but nothing to actually throw the breaker...?

I can't imagine the leaf's onboard charger briefly asked for more than 50 amps and the EVSE should have rejected that anyway, right? Therefore I'm thinking the EVSE for some reason briefly pulled over 50 amps. Is that a safe bet?

LeftieBiker
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 11:58 am

Defective breakers are pretty common, and you don't hear much about them because they usually - but not always - fail by failing to trip. It isn't a GFCI breaker, is it?
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ripple4
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 2:31 pm

The first step is to see if there is continuity between either line and ground. Next pull of the covers on the outlet and inspect what you can. Is it aluminum or copper wire? Since it happened after some time it could be those fat wires growing a little and making contact on a sharp edge.

EatsShootsandLeafs
Posts: 710
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 3:53 pm

It’s not a GFCI breaker.

The cable is aluminum.

I’ve run a couple more events and at 6.6 kWh rate it goes for about 30 (9% charge last time) min then trips. Surely this means there is good continuity and no catastrophic short or loss of circuit somewhere...?

I’ll check continuity... edit: done, but probably too stupid to know how. I know my multimeter is set to continuity mode as I was using it this week on an electric fence, and the electrodes when touched together confirm it. However, no combination of poles in the socket itself generate any apparent continuity. Since the charger works for a while I assume I’m just doing it incorrectly.

goldbrick
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 4:14 pm

Is the receptacle rated for Al wiring? Did you use anti-oxidant paste on the wire ends when installing the receptacle? Are the wire connections tight?

I'd guess it's a faulty breaker but check all those things first. If it still keeps happening I'd call the electrician back since this will wear out the breaker in time and may not be 100% safe at the moment.

SageBrush
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 5:19 pm

Working with Alu wiring is tricky.

Coward that I am, I would swap out the breaker for a new one and call in an electrician to reinstall the 14-50 receptacle.
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 5:28 pm

Do you have a amp probe? If so clamp each phase and see what ur drawing.
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EatsShootsandLeafs
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 6:02 pm

I definitely didn’t use paste but I only installed receptacle three months ago. I definitely made it very tight. I had no idea a 14-50 receptacle had to be rated for that or not.

I don’t have an amp probe.

The electrician was not somebody I want back (was a “get the job done quick” sort of guy, which is why he never installed the 14-50 either—house was a new build and he wasn’t very detail oriented ), but I am thinking a breaker replacement may be the simplest thing to try. I found installing the 14-50 to be a huge pain due to the stiffness of the wire so in no hurry to redo that!

Here's a pic of breaker for what good this is. I do not see indication of paste, whereas the 200 AMP wiring into the breaker does have some paste.

For what it's worth I have the car charging right now for about 10 minutes and the red wire here is very mildly warm. The black, however, is very hot. In fact, right next to the breaker I can only touch it for around 10 seconds before it's just too hot to touch. As I get further from the breaker it cools down, so a ton of heat is hitting that black wire right at the breaker.

Image

Flyct
Posts: 428
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 7:18 pm

You said it’s wired with 60 amp rated aluminum wire? That’s unusual to use aluminum rather than copper and that’s some thick stuff.

Sounds like a defective breaker or a poor connection at the breaker.

Does the breaker get hot to touch? If so after it trips I would feel each of the 2 wires at the breaker. A poor high resistance contact at the breaker will heat up the wire and the breaker.

A poor contact on a breaker can really heat things up. This is an example of a 15 amp double pole breaker with high resistance where it connected to the panel backplane. This is from my sub panel.


Image
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Flyct
Posts: 428
Joined: Tue Nov 03, 2015 12:04 am
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Re: Breaker thrown. I wonder what root source of problem was?

Fri May 07, 2021 7:23 pm

EatsShootsandLeafs wrote:
Fri May 07, 2021 6:02 pm
I definitely didn’t use paste but I only installed receptacle three months ago. I definitely made it very tight. I had no idea a 14-50 receptacle had to be rated for that or not.

I don’t have an amp probe.

The electrician was not somebody I want back (was a “get the job done quick” sort of guy, which is why he never installed the 14-50 either—house was a new build and he wasn’t very detail oriented ), but I am thinking a breaker replacement may be the simplest thing to try. I found installing the 14-50 to be a huge pain due to the stiffness of the wire so in no hurry to redo that!

Here's a pic of breaker for what good this is. I do not see indication of paste, whereas the 200 AMP wiring into the breaker does have some paste.

For what it's worth I have the car charging right now for about 10 minutes and the red wire here is very mildly warm. The black, however, is very hot. In fact, right next to the breaker I can only touch it for around 10 seconds before it's just too hot to touch. As I get further from the breaker it cools down, so a ton of heat is hitting that black wire right at the breaker.[]

Image


HIGH RESISTANCE CONTACT AT BREAKER WHERE BLACK CONNECTS.

turn off power, remove and fully reseat the black wire and retorque the set screw.

If it still gets hot replace the breaker.
Last edited by Flyct on Fri May 07, 2021 7:31 pm, edited 1 time in total.
2020 Leaf SL Plus (replaced totaled 2019:SL+)
2015 Lexus RX450h Hybrid SUV
2019 F-150 XLT Extended cab
2020 Ford F-350 Lariat Ultimate Crew Cab Short Bed Diesel- Tow vehicle
2017 Grand Design Reflection 337RLS 5th Wheel RV

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