Burn marks on Apple charger plug pins

[bd139]

Noticed this today. Thought it was interesting. If you look at my Apple charger here there are burn marks on the plug pins. Clearly due to the inrush current when plugging in. I dread to think what this does to the switches in the socket face plate.

See attachment

[Halcyon]

You don't have switched outlets?

[bd139]

I do however I'm lazy some of the time and I wonder what this actually does to the switched outlet contacts.

[Zero999]

I do however I'm lazy some of the time and I wonder what this actually does to the switched outlet contacts.

It's better to use the switch because it's designed to make/break the load. Whilst UK mains plugs will withstand this kind of abuse, it's not good.

[bd139]

Fair points.

I think this lazy happens because the blocks I have aren't individually switched per socket.

Can anyone recommend a half decent individually switched trailing socket block at all? (Not Brennenstuhl / generic crap)

[Electro Detective]

All the apple gear I've come across, does to not like to be jiggled into a live power point

Best to use a switch, unless you like apple's replacement prices 

[glarsson]

All the apple gear I've come across, does to not like to be jiggled into a live power point

Large (most?) parts of the world do not have switched sockets. We don't, and I have never seen this cause problems for any of my Apple gear.

[Electro Detective]

Australian 240 volt 'non-round' slit style sockets must be different to yours, they can be very unforgiving to plugs that are forced/jiggled in with power applied

Anyway I'm sick of cleaning black spark gunk and filing down welder style metal spikes from appliance plugs and troubleshooting abused power sockets,

so here in oz it's   'plug in, then switch on'  for me!   

[JPortici]

All the apple gear I've come across, does to not like to be jiggled into a live power point

Large (most?) parts of the world do not have switched sockets. We don't, and I have never seen this cause problems for any of my Apple gear.

Or any gear at all. same for me

[RGB255_0_0]

I'm not sure what metal/alloy they make their plugs from but it doesn't look like brass to me. My MagSafe charger features those same black marks.

[bd139]

At least it's not just me.

My other apple charger (diddy one for phone) doesn't have these burn marks

[electr_peter]

Plug does not look too bad in the pictures. I have seen laptop power supply with Euro plug C (CEE 7/16) in much worse condition (pitting on pins). See added pictures.

[Ampera]

I live in the US with NEMA outlets (flat prongs, normally seen on cheap chinese crap). We don't have switched outlets (we barely just got shutters on US outlets) and I have never in my life seen anything of this sort. I have never had burnt plugs, and I've never seen it before on US, Europlug, or Shucko (I use all three in my house) plugs.

[bd139]

You don't have as many volts over there though

[Ampera]

You don't have as many volts over there though

But wouldn't it be the current doing it? To be fair a normal UK ring mains circuit is I think around 32A, and a standard european is around 16A while ours are 15A.

Whatever, I don't have the EE knowledge to figure that out. I'm here to learn about it, less teach it. I've got computing experience for that.

[bd139]

I think the higher voltage is more likely to form an arc during the bounce that happens when you plug something in.

[alm]

What bd139 says, maximum arcing distance (dielectric breakdown of air) is pretty much linear with voltage (obviously depending on socket construction and other factors).

Whatever, I don't have the EE knowledge to figure that out. I'm here to learn about it, less teach it. I've got computing experience for that.

Teaching is an excellent way to learn a subject.

[vodka]

Noticed this today. Thought it was interesting. If you look at my Apple charger here there are burn marks on the plug pins. Clearly due to the inrush current when plugging in. I dread to think what this does to the switches in the socket face plate.

See attachment

When did you insert the pins on the plug , you didn't hear any sound like spark? I have two charger of laptops when i plugged to plug , it made sounds seemed to sparks(i confirmed that its pins are erosioned).
Too, i realized that this trouble always  is produced by  the Switched Power Supplies, never by the Linear power supplies.

[G7PSK]

I have seen burn marks like that before on UK plugs, it's due to the sockets, the sping tension on the contacts slacks, it can even lead to fires with a bigger load. Happens more frequently with cheap Chinese sockets and extension leads.

[TheDane]

Too, i realized that this trouble always  is produced by  the Switched Power Supplies, never by the Linear power supplies.

It is most likely due to the low ESR of the capacitor inside, after rectification from mains AC to DC.
230Vac rectified is normally over 300Vdc, and most caps have ESR values below 0.1 ohm... The initial inrush current is enormous, if plugged in at max voltages.
Protection costs, and Fox Con   

I wouldn't recommend freezing your SMPS before powering it up, but that effectively raises ESR value, if it's an electrolytic cap 

[Gyro]

Yes, that looks like high inrush current to me too. It reminds me of the crack you hear when you plug the IEC lead into a laptop adapter. A bit surprising for an adapter of that size though.

[Zero999]

Yes, it's the high surge current, when it's powered up. It's poor design, they should have added something to limit the inrush current. Another option is to not have a big smoothing capacitor and using an active power factor correction unit, but that would probably be too expensive.

[bitseeker]

This happens to me on 120V with both MacBook Pro and iPad power supplies. Poor design for such "high tech" and expensive wall warts. Granted, the fake Apple chargers are even more poorly designed, but it's highly disappointing that a brand name charger arcs so often. I don't have that problem with my Acer, Samsung, and LG chargers.

[bd139]

My (genuine) Lenovo one does it as well by the looks. No burn marks but lots of pops.

I imagine it stresses the front end rectifiers as well.

[Electro Detective]

Loose, tight, misaligned sockets,

silly socket safety shutters that never work properly, or are just plain fkt by improper usage or design (usually the former PLUS latter) 

bent plug pins,

corroded or tarnished contacts

cheap crappy -Made In Chynna Allleyways- powerstrips/boards   

all contribute to DIY fireworks that isn't doing your equipment any favors 

Might even blow an internal fuse or trip a sensitive circuit breaker or RCD/GFCI etc

Not worth the hassle or drama stressing your electronics every time you plug in and gamble it will work 'like last time' 

get a switch into the equation ASAP