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by aianus 3518 days ago
> Three-pin appliances require a ground to be safe

Can you elaborate on this?

My MacBook charger has both a two-prong and a three-prong cable. Why would it be any more dangerous to plug my MacBook into this power strip using the three-prong cable than to connect it directly to the wall with the two-prong cable?
1 comments
chx 3518 days ago
Your MacBook then is prepared for ungrounded operations. Now take a laser printer, it uses very high voltage on the inside and if something gets dislodged and touches an outer facing metal part and you touch that in turn, you are dead. That's why the outer parts are connected to a safety ground. Do note Xerox warns you not to use a "cheater plug" http://download.support.xerox.com/pub/docs/4400/userdocs/any... . Laser printers are also a great example of when that C7/C8 connection is a fire hazard because laser printers need a lot of power when heating up their fusers. This is also why you must not connect a laser printer to a UPS.
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spoiler 3518 days ago
It's also possible that op has a socket like this, so the grounding is on the side: http://i.imgur.com/lLM3gQO.png

However, there is also this: http://i.imgur.com/ftPT7sC.png, which grounds from either sides or in the middle for sockets like these http://i.imgur.com/FnXMndC.png

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aianus 3518 days ago
No, I have American sockets.

The charger looks like this: https://support.apple.com/library/content/dam/edam/applecare...

And also comes with a longer, three-prong cable that replaces the little two-prong piece: http://www.ebay.ca/itm/like/172352962036?lpid=116&chn=ps

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sveiss 3518 days ago
The MacBook chargers are designed to be safe without grounding.

The grounding pin does have a use, though: some cheap powered USB devices will put out a voltage relative to ground on their '0v' lines. If you touch a MacBook that's plugged into one of these devices, you can get a small shock. If you're using a 3-pin adapter, this doesn't seem to happen.

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