Replacement power supply adapter doesn't have ground prong - dangerous?

February 20, 2014 8:31 PM

The replacement power supply adapter I purchased for an older laptop came with a two prong cord instead of three, which the original had. Is this dangerous? Details and model number within.

Due to a frayed cable, I bought a replacement power supply for an older Dell laptop, making sure to buy one that stated OEM/Genuine instead of the off market "Replacement for..." that I saw a lot of on ebay.

But when it came, it has a two prong power cord instead of three. Is it dangerous not to have the ground prong? I don't know much about electricity, except that I don't want to be the guy that burns down my apartment complex because of a crappy power supply or, say, a cheapo laptop battery. In every other regard (craftsmanship, design, stickers) it appears to be a legit OEM part, it just says Revision A07 instead of Revision A00, like my original.

It's a Dell PA-12, 65W adapter. Here's the ebay link.

Thanks for your advice.

posted by bluecore to Computers & Internet (9 answers total)

It is not inherently dangerous to have a two-prong cord versus a three-prong cord. Many laptops have them. On the other hand (and while this is not to say it's necessarily unsafe for this reason either) it's probably not very likely that you're actually getting a genuine adapter when you buy from overseas on eBay.
posted by karbonokapi at 8:41 PM on February 20, 2014 [1 favorite]

Bettin' on it will be just fine.
posted by Freedomboy at 8:41 PM on February 20, 2014

Your adapter is entirely safe. It may not meet EMC requirements.

Article on why three prongs are often used.

Article on cheap AC adapters and EMC requirements.
posted by Confess, Fletch at 9:00 PM on February 20, 2014

On the other hand, cheap crappy AC adapters definitely cause fires. My daughter just had the one on her Macbook burn up (not an Apple device, no-name, bought cheap online.) A few years ago the neighbors almost lost their house to a burning wall transformer igniting some curtains.
posted by billb at 9:24 PM on February 20, 2014

my elderly sony vaio laptop has a two-prong plug, it's some concern when my cat screws with the plug, no concern that it will electrocute me.
posted by bruce at 9:34 PM on February 20, 2014

That is a real dell charger, and you should be fine. Ebay has a serious ban on counterfeits, and you can't use the phrase "genuine" without getting slammed pretty damn quickly.

The fake chargers are half that price, $20~ is the price that gets you a real one.

I came in here to warn you about fake cheapass chargers, but this isn't one.
posted by emptythought at 10:50 PM on February 20, 2014

Keep in mind, too that the standard mac charger has two prongs when plugging directly into the wall, but the cord attachment has three. Mix and match.
posted by Admiral Haddock at 3:04 AM on February 21, 2014

When I worked at Dell there were extra power plugs in the supply closet. Although the power brick to the notebook is specific to the model, the removable cord from the brick to the wall plug could have either 2 or 3 prongs (or European or Asian plugs). I preferred the two prong since it was more universal in that I could plug it into any extension cord.
posted by birdherder at 6:49 AM on February 21, 2014

Assuming the power supply is compliant with regulation all a two prong plug means is the power supply is double insulated and doesn't require a connection to ground. It's really popular in power supplies because by their nature they isolate the DC output from the mains power.
posted by Mitheral at 10:18 AM on February 22, 2014