Is it safe to disconnect a SATA cable while PSU is on?

donaastor · 2025-02-08 03:41:43

I am very sorry for asking this question here while it can stand independent of Linux completely, but other forums reject it.
I know this forum has very nice people, so I ask for help, please.

While a computer is not running, but its PSU is connected to wall and switched on, can I disconnect a SATA cable from a HDD/SSD (the power supply cable of the disk would still be connected to the disk)? Can I do the same but now reconnecting the SATA cable? I am assuming it is safer to do this with the SATA cable instead of both the SATA and the power supply cable, is this correct?

seth · 2025-02-08 11:03:22

Depends on what you consider "safe" you're not supposed to deal w/ any major voltages here nor should there be any current on that cable when the system isn't powered on.
Problem is the shouldland part - if the hardware is damaged in any way, pretty much everything can happen.

That being said: if you trust the hardware you can do this while the system is running: https://en.wikipedia.org/wiki/SATA#Hot_plug but it's not a good idea to do this (or rather withdraw the power supply) while a HDD is spinning and pulling the conneciton while the disk is in active use by the OS will cause filesystem corruptions for pretty much sure.

Rather make sure you're earthed (I hope that's the correct english term, WP uses it) because otherwise you can fuse stuff with static build up inside you (though in reality I just briefly touch some earthed metal, preferably a radiator or so, to get rid of that)

ewaller · 2025-02-08 15:39:55

'Earthed' in the UK. 'Grounded' in the USA. I imagine Canada is Grounded and Australia are Earthed.

As to personal safety, if the supply carries regulatory markings (CE, UL, C-Tick) and is properly connected to the line (mains) you should be fine.

What do you mean by 'computer is not running, but its PSU is connected to a wall and switched on' ?. I take that to mean it is an ATX style power supply, it is supplying housekeeping power to the main logic board for power sequencing logic and standby battery charging. The supply is in standby mode and is not providing power to the computer itself (CPU, GPU, I/O, Memory).

In this state, you can connect and disconnect the disk cables to your heart's content. I like to attach the power cable first and disconnect it last. It provides a signal ground. The drive 'should' have a chassis ground by virtue of being mounted in the chassis -- if it is mounted in the chassis.

Disconnecting a cable while the power is ON could cause issues in power sequencing. Also, it could leave voltages on inputs that are beyond the power pins as should the power disconnect before the signal connection. But, most logic protects itself pretty well at the hardware level. The state of the file system, on the other hand, could be compromised. If this ever happens, DO NOT reconnect that cable while things are powered.

As Seth points out -- use an ESD wriststrap anytime you touch things. https://www.amazon.com/esd-wrist-straps … ist+straps

Last edited by ewaller (2025-02-08 15:40:51)

eriefisher · 2025-02-08 16:56:01

It seems completely crazy to be disconnecting/connecting things while there is active power to the device. Is there some reason you can't turn off and/or disconnect the psu? It may not hurt the device in question but what if the connection is tight ot troublesome and you slip and hit something else? Why take the chance for an extra two seconds of your life.

ewaller · 2025-02-08 17:04:32

However, disconnecting the computer from the mains also disconnects it from Ground/Earth.

Arch Linux

#1 2025-02-08 03:41:43

Is it safe to disconnect a SATA cable while PSU is on?

#2 2025-02-08 11:03:22

Re: Is it safe to disconnect a SATA cable while PSU is on?

#3 2025-02-08 15:39:55

Re: Is it safe to disconnect a SATA cable while PSU is on?

#4 2025-02-08 16:56:01

Re: Is it safe to disconnect a SATA cable while PSU is on?

#5 2025-02-08 17:04:32

Re: Is it safe to disconnect a SATA cable while PSU is on?

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