Question about power/current in monitor cords?

W10 Tweaker said:

Changing connections between devices while powered is usually a bad idea, however; if both devices are powered by the same power source and have a 3 prong grounded plug, I suspect your little spark will disappear at 63%rh. Just an educated guess from working at large Com site's for many years.

Ok so I had a pretty good idea on what you was gonna suggest, so I plugged my monitor into the same power strip and no more sparks was seen by doing the same actions, but before I switched I touched the metal part of the HDMI cord while holding the plastic part to a case fan screw and got a spark these are super small sparks mind you but a spark none the less, anyways plugged in to same power stripe as mini itx build and no more sparks so I will double check again on my next break and update the post and when I get home too... However I have a question, why would it still cause a faint spark with the monitor unplugged entirely from the old source? Does the monitor keep a slight charge after being unplugged? If anything the strength of the mini spark has significantly been reduced I couldn't see any in the dark after plugging both monitor and pc into same power strip.

My brain is a bit tired and possibly not that sharp.

The test you just performed using the same power circuit, was this at work? If so, is your monitor rack mounted in a steel rack?

W10 Tweaker said:

My brain is a bit tired and possibly not that sharp.

The test you just performed using the same power circuit, was this at work? If so, is your monitor rack mounted in a steel rack?

Ill sum it up Monitor + Pc same strip = no visible sparks in dark
Monitor on different power strip = noticeable sparks, when running between GPU backplate and chassis / or touching case fan screw head.

This was tested at work, Government building and 3 prong power strip. No it is just sitting on top of a SFF dell PC.

P.S. Monitor has multi input and they have the work pc hooked up via VGA cable... I use the hdmi slot for my personal mini itx build I leave on my desk while im here lol.

https://www.amazon.com/Belkin-12-Out.../dp/B000JE9LD4
This is what I use at home.

W10 Tweaker said:

There is always the possibility of any device maintaining a very low amount of charge after being unplugged but having devices powered on different circuits is just asking for a potential difference resulting in some amount of sparc when the ground are connected such as through a cable or cable shield.


I again have to suggest reading up on ground loop for the theory behind potential difference. It often will appear as hum, however; potential difference is a potential difference and will equalize at the first opportunity through any ground connection, cables or fingers if you have good conductivity to a different ground d potential.

I will read up on this, Thanks for the suggestions go get some sleep! come back tomorrow evening ill update my home post and see if I get the same result!

I'm happy you're finally getting results and now have theory to investigate. Enjoy the adventure,

Michael

Next time touch the back of the work computer (Metal case part) without holding any cables or electronic devices. This will drain off residual static and then make sure that you are doing this before hooking up monitors.

Never grab the metal of any computer or TV connection cords. This can cause a static surge through that ground plane and fry sensitive electronics. Tv's and stereos get fried from surges and lightning storms because the surge travels through the ground of the cables, especially with HDMI cables daisy chaining multiple devices, the damage can end up worse.

We always used grounding wrist straps and stood on electrostatic mats while working on sensitive electronic items.

bro67 said:

Next time touch the back of the work computer (Metal case part) without holding any cables or electronic devices. This will drain off residual static and then make sure that you are doing this before hooking up monitors.

Never grab the metal of any computer or TV connection cords. This can cause a static surge through that ground plane and fry sensitive electronics. Tv's and stereos get fried from surges and lightning storms because the surge travels through the ground of the cables, especially with HDMI cables daisy chaining multiple devices, the damage can end up worse.

We always used grounding wrist straps and stood on electrostatic mats while working on sensitive electronic items.

I had on a static band from ifixit and was touching the metal chassis, static is easily and quickly discharged. This was a live current and was easily recreate-able I understand what you was saying about static but this wasn't static it was like... When you clash together the negative and positive cable of a car your jump starting. Just on s much smaller scale. So unless I was going super saiyan there should of been no static from me to machine between the bands and touching the metal chassis. However I didn't have a grounding mat but it was a tile floor, and my shoes was anti slip with dr scholls gel in souls, love those things... Lol

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Ok testing at home, same issue as at work they disappear once plugged into same strip/surge protector

Monitor off plugged in spark on case screw or chassis vent with club3d cable while touching the metal chassis myself.

Monitor powered on diff strip spark.

Monitor on same strip no spark

Pc powered on diff strip gives spark

Same strip no spark

In all my years of building pcs I have never come across this lol this is fascinating
I dont believe its static as its on a marble stand and repeated touching would dissipate the static charge

I did that, and there is nothing on either machine touching anything there shouldn't be. Both quality power supplies and modular, nothing more is plugged in then what needs to be, and all stand offs are screwed down snugly. The mini ITX is a newer build within the last 2 months. The home pc is months old now and performing well, ram checks out no errors even the event log and reliability meter is pretty clean.

Home, x470 gaming 5 wifi 2700x, amd flare x 2933, evga 1660ti
work, mini itx b450 I, corsair lpx dominator 3000, evga 1660ti

both on nvme samsung drives and gigabyte boards. Idk if this helps any.