Question Should a Universal laptop power adapter be grounded?

Rodion15

Distinguished
Sep 11, 2011
701
6
19,015
7
May be I should have asked:
Should ANY laptop power adapter be grounded?

As a computer repair tech, I always wondered why some power adapters for laptops come with a ground pin on the AC plug and others don’t.

Example: Macbook Pros in the UK have 3-prong AC plugs with an actual metal ground pin.

Other laptops I’ve seen have a plastic (dummy) ground pin or no ground pin on the AC plug.

I’m planning to buy two Universal Power Adapters:
  • USB-C Power adapter (up to 100w with USB-A and USB-C ports)
  • Multi-tip Universal Power Adapter for all laptops (barrel tips).
Should they have a ground prong on the AC plug?

Any advice much appreciated.
 

Rodion15

Distinguished
Sep 11, 2011
701
6
19,015
7
May be I should have asked:
Should ANY laptop power adapter be grounded?

As a computer repair tech, I always wondered why some power adapters for laptops come with a ground pin on the AC plug and others don’t.

Example: Macbook Pros in the UK have 3-prong AC plugs with an actual metal ground pin.

Other laptops I’ve seen have a plastic (dummy) ground pin or no ground pin on the AC plug.

I’m planning to buy two Universal Power Adapters:
  • USB-C Power adapter (up to 100w with USB-A and USB-C ports)
  • Multi-tip Universal Power Adapter for all laptops (barrel tips).
Should they have a ground prong on the AC plug?

I also noticed that most US plugs for laptop adapters don't have the ground pin, while UK ones sometimes have it. I wonder if the UK ground prong is really grounded to the metal case on the laptop or to the internal ground such as on the motherboard.

Any advice much appreciated.
 
Last edited:

AntonyLovric

Distinguished
Aug 4, 2014
342
25
18,890
48
One thought, if there is ANY chance you're working outside / exposed to moisture, it would be safer to have a ground plug. I think ARC Fault / GFCI's will also be able to provide more coverage / safety if ground is present.

Side note: Even if you have a ground line on the power adapter the ground may or may not terminate at the power brick, (the +/-DC output might or might not be tied to ground through the negative (-) terminal.
 
Reactions: Rodion15
May be I should have asked:
Should ANY laptop power adapter be grounded?

As a computer repair tech, I always wondered why some power adapters for laptops come with a ground pin on the AC plug and others don’t.

Example: Macbook Pros in the UK have 3-prong AC plugs with an actual metal ground pin.

Other laptops I’ve seen have a plastic (dummy) ground pin or no ground pin on the AC plug.

I’m planning to buy two Universal Power Adapters:
  • USB-C Power adapter (up to 100w with USB-A and USB-C ports)
  • Multi-tip Universal Power Adapter for all laptops (barrel tips).
Should they have a ground prong on the AC plug?

Any advice much appreciated.
They don't have to have a ground pin, but if you're using a laptop with an aluminum chassis, you're going to want one.

When I worked at Razer on the first version of Blade, we wanted to make the adapter as small as possible so we used a C7 power cord (no ground pin). Now, when I was testing, I was either wearing shoes or standing on a carpeted floor. :D But apparently, some people use their laptops with sweaty bare feet and they were complaining about feeling a tingle through the Blade's aluminum chassis. We had to go back and uglify my beautiful power brick by making it larger so it could utilize a C5 power cord (with ground pin).
 

Rodion15

Distinguished
Sep 11, 2011
701
6
19,015
7
Thanks for your great answers.

I made some tests with a multimeter, confirming that NO, the laptop chassis is not connected to the AC mains ground.

I tested on a Macbook Pro 2015, a Windows laptop and a Chromebook.

The negative on the laptop charger is connected to the chassis/motherboard on these.
 

Rodion15

Distinguished
Sep 11, 2011
701
6
19,015
7
They don't have to have a ground pin, but if you're using a laptop with an aluminum chassis, you're going to want one.

When I worked at Razer on the first version of Blade, we wanted to make the adapter as small as possible so we used a C7 power cord (no ground pin). Now, when I was testing, I was either wearing shoes or standing on a carpeted floor. :D But apparently, some people use their laptops with sweaty bare feet and they were complaining about feeling a tingle through the Blade's aluminum chassis. We had to go back and uglify my beautiful power brick by making it larger so it could utilize a C5 power cord (with ground pin).
Thanks for your nice answer.

I tested with a multimeter on my 2015 Macbook Pro and the metal case is not connected to the AC plug "mains" ground prong. So there's no grounding.
 

ASK THE COMMUNITY

TRENDING THREADS