Switch melting when charging Leaf

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ajbw

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#298443 17-Jun-2022 18:10

The two pictures are of the inside front and back of a PDL 10A mains switched double socket.

If you look at the back picture, you will note that the two squares at the top corners - where the switches are - have a 'bumpy' appearance. This is because the plastic has started to melt.

I first noticed some months ago that the area around the switch was getting warm after an hour or two of charging, so used the other socket of the pair. Now both are unusable.
In the pictures, the internal contact rockers are (just) visible below the switch. They are significantly burned.

The charging system is an OEM audio portable charger rated at 8A. My measurements, and the display, say that the charging current never exceeds 7.5A.

I have replaced this with a 15A switched socket - we'll see how that goes.

But I have couple of questions for the electricians amongst us:

1) The socket has been operated within its rating. Why has it burned out?

2) Should some agency be investigating the manufacturer's safety and spec conformance claims?

3) Why are there 10A and 15A sockets which appear to be identical from the outside, and what is the actual difference?
( and I know the 15A has a bigger earth pin,but that is not relevant here, as no current has ever gone down that).

Please enlighten me - and check your mains sockets!

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#2931137 17-Jun-2022 19:40

Do your measurements include power factor? I would not expect power factor to make over 25%+ difference so just asking.

gzt

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#2931187 17-Jun-2022 19:52

Disclaimer: not an electrician.

Any aspect of high resistance in the contact paths can make a difference. Heat tends to migrate to the weakest point and make things worse. Installation/maintenance can be a factor if terminals are loose or otherwise badly done. I've seen this kind of issue occur with low current loads on multi-boxes and the like. I've seen it once on a wall socket.

Obviously it can be even worse with high current devices. My advice is have this checked by an electrician.

tweake

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#2931188 17-Jun-2022 19:59

i would be inclined to check the amp draw of the charger. 7.5 amps charging, add extra due to efficiency loss and your right at 10 amp or so. short term loading is not an issue (like a welder, big amps but short time frame).

i would upgrade to 15 amp sockets, they typically have better contacts, better bars, better pin connectors etc.

ajbw

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#2931202 17-Jun-2022 20:53

Thanks for your comments.

I've measured the power factor. It's pretty close to 1,
and in any case I'm measuring current here, and it's 7.5A.
Charging efficiency doesn't come into it - this is the current measured at the mains socket.
The socket was installed by an electrician, and I did check the screw terminal tighness. But as I mentioned, there is no heat at the terminals or at the plug pins. The heat is at the switch itself, and the switch contacts are obviously burned.

tweake

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#2931206 17-Jun-2022 21:06

7.5a is not much of a load. the contacts don't look bad, seen much much worse than that. but the burn marks on the rocker connection is of concern.

the other possibility is cost cutting on the rails. a lot of cheap ones now are plated steel instead of copper.

recently i've had a relay go bad at work. 6.4a through a 14 amp relay (good euro brand) and its cooked, and didn't trip the breaker either. bad materials in the supply chain???

Tinkerisk

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#2931259 18-Jun-2022 04:46

ajbw:

The charging system is an OEM audio portable charger rated at 8A. My measurements, and the display, say that the charging current never exceeds 7.5A.

Please enlighten me - and check your mains sockets!

Do you have the switch conntected on the primary (AC) or secondary (DC) side of the charger?

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gregmcc

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#2931260 18-Jun-2022 05:53

You can get sockets without a switch.

Ask for a specification sheet as it seems the switch mechs are not lasting like they should.

What brand/model is this socket?

Tinkerisk

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#2931262 18-Jun-2022 06:02

Tinkerisk:

ajbw:

The charging system is an OEM audio portable charger rated at 8A. My measurements, and the display, say that the charging current never exceeds 7.5A.

Please enlighten me - and check your mains sockets!

Do you have the switch conntected on the primary (AC) or secondary (DC) side of the charger?

I mean, I just ask because the housing of the switch clearly states A.C. only and here is why D.C. could be the problem.

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Daynger

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#2931335 18-Jun-2022 11:27

gregmcc:

You can get sockets without a switch.

Ask for a specification sheet as it seems the switch mechs are not lasting like they should.

What brand/model is this socket?

Looks like a PDL 600 series, 692w vertical.

The switch part will be the weak point in the power outlet for sure as that is always where they burn out first and they usually show heating on the back as shown in the first picture.

OP, you will likley find they are rated to a maximum of 10A but there may be a time limit on this to deal with heat soaking the outlet although i havnt seen anything like this.

Looking at your pics again you can see on the copper rocker that sits in the switch and does the connection it is all pitted, this will be from switching the high load and over time more pitting leads to a higher resistance connection which leads to heat.

Scott3

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#2931350 18-Jun-2022 12:55

Tinkerisk:

I mean, I just ask because the housing of the switch clearly states A.C. only and here is why D.C. could be the problem.

For clarity, the leaf charging setup is as follows.

File:Nissan LEAF Charge Port.jpg - Wikimedia Commons

AC charging:

Liquid cooled AC charger is mounted in the car, and the car is fed with via it's single phase type 1 AC port (the one on the right). The conversion to DC is largely invisible to the user. The two extra pins on that port are for communication with the EVSE (Basically a box with some electronics and relays. It is either wall mounted, or a brick in a charge cord). The car communicates with the EVSE, and tells it when the earth is good, and to liven the wires running to the car. EVSE communities with the car and tells it the Maximum AC current it can draw (typically 8A in the case of non thermally monitored cords that plug into 10A sockets).

Nissan leaf chargers onboard can handle a min of approx 6A, and a max of either approx 16A or 32A depending on version.

99%+ of home charging is AC, as DC chargers cost tens of thousands of dolars.

DC: charging.

Off board charger that is far more powerfull than the something / 6.something kW onboard chargers. Commonly used in public locations for a few. Most common units are 50kW.

Extremely rare to use at home due to cost.

In this case, OP is using a portable charge cord (A 10A plug wired to a brick style EVSE, wired to a 5 core cable, going to the AC type 1 port), charging the leaf with AC power going to its onboard charger.

Bung

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#2931370 18-Jun-2022 14:28

The Electricity Safety Regs don't allow the common 3 flat pin sockets to be used for anything other than 230v AC.

"61ARule about 3-pin flat-pin socket-outlets in low voltage installations
(1)
If a 3-pin flat-pin socket-outlet that has the dimensions specified in AS/NZS 3112 is, or is to be, installed in a low voltage installation, it must be installed in such a way that—
(a)
the socket-outlet may be supplied with electricity only at standard low voltage; and"

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richms

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#2931376 18-Jun-2022 15:14

PDL are not what they used to be. I have had ones in the kitchen start to have the switch feel gritty when moved and looked like that when removed. That was just running normal kitchen loads like deep fryers and kettles etc. These are ones I swapped over for some HPMs that had been in place for ages but were just looking old and tired.

Now have a 4 or 5 way deta in place, and so far those are holding up fine with the same loads.

Richard rich.ms

cyril7

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#2931381 18-Jun-2022 15:27

Daynger:

gregmcc:

You can get sockets without a switch.

Ask for a specification sheet as it seems the switch mechs are not lasting like they should.

What brand/model is this socket?

Looks like a PDL 600 series, 692w vertical.

The switch part will be the weak point in the power outlet for sure as that is always where they burn out first and they usually show heating on the back as shown in the first picture.

OP, you will likley find they are rated to a maximum of 10A but there may be a time limit on this to deal with heat soaking the outlet although i havnt seen anything like this.

Looking at your pics again you can see on the copper rocker that sits in the switch and does the connection it is all pitted, this will be from switching the high load and over time more pitting leads to a higher resistance connection which leads to heat.

Looking at the switch tops, it looks like an Iconic

Cyril

Tinkerisk

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#2931384 18-Jun-2022 15:36

Scott3:

For clarity, the leaf charging setup is as follows.

AC charging:

In this case, OP is using a portable charge cord (A 10A plug wired to a brick style EVSE, wired to a 5 core cable, going to the AC type 1 port), charging the leaf with AC power going to its onboard charger.

Thanks for clarification, my Twizy works as simple like that but I use an AC SSR to prevent electrical arcs instead of a mechanical switch. And I was wondering about the ‚OEM audio portable charger‘ that implied to me the use of a separate DC charger.

Then either the switch could be destroyed by time due to a higher inrush current of the AC charger or it‘s simple a quality issue. :-)

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Daynger

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#2931443 18-Jun-2022 17:14

cyril7:

Looking at the switch tops, it looks like an Iconic

Cyril

Nah, iconic has the three terminals side by side and they are in green plastic.

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