USB and DC soldering irons can kill electronics when mains powered

[Gripless]

When running from battery there is no issue since nothing is grounded. Same applies to running from power banks.

 

TLDR;

keep them away from car electronics when powered from the wall.

Wires etc are ok to solder if not connected, eg making a loom disconnected from the car.

Anything with integrated circuits, chips will likely suffer some damage.

 

 

Seems this is well known in electronic circles but not communicated widely outside.

When powered from wall socket they have floating ground which while super low amperage can be in the 40-70v range between tip and you skin. You won’t feel or notice this at all.
Wearing a grounding strap actually make it’s worse as then all that voltage will have somewhere to go.

 

The irons are built correctly and connect the tip to usb shielding, it’s a power supply issue.
The problem comes from the fact modern USB or DC power adaptors do not ground the shielding of the cable that the iron needs to discharge the static ESD. Eg Apple used to ground there adaptors but newer usb-c ones some are some aren’t.

 

Seems the USB standard does not specify which end should be grounded as grounding both ends and having more than one thing plugged in can cause more issues.

 

 

There are fixes I won’t link to as playing with wall plugs even if just plugging into the earth terminal needs some understanding.

 

Many irons now come with special grounding wires to plug into the wall so if you have this then you should be ok.

[boon]

No serious electronic work should ever be done with a soldering iron that can run off a USB port anyway.

[Gripless]

32 minutes ago, boon said:

No serious electronic work should ever be done with a soldering iron that can run off a USB port anyway.

That used to be the case but the newer ones run of PD or QC so 20v 3-5a from laptop power supplies.

 

The one I have is 60 watts and some are 100w and they use the same changeable tips as the mains powered ones.

 

I only did a couple of speaker wires and some microcontroller stuff and it work very well. Other than the grounding issue that is solvable once you know it exists.