Alternatives to running a ground wire?

July 30, 2009 11:39 AM

Will a surge protector or UPS plugged into an ungrounded outlet do anything to protect my electronics in the event of a power surge?

There are conflicting answers to this question online.

Is there anything I can plug my computer/tv/electronics in to to protect them from power surges on an ungrounded outlet, or is the only solution to actually ground the outlet in question?

posted by nitsuj to home & garden (8 comments total)

You need to ground it. How surge protectors work. You can't just leave the ground floating - the surge protector won't do anything in that configuration. Well, it will let all the surges through, that's what it will do.
posted by GuyZero at 11:42 AM on July 30

Why not protect the whole house?
posted by Gungho at 11:53 AM on July 30

Well, leaving aside the question of whether a surge protector wll help even if the outlet is grounded…

Surge protectors can work in the absence of a ground (they crowbar between hot and neutral instead). Depends on exactly how your particular surge protector is made; they vary a lot. Of course, they wouldn't be able to do anything about a common-mode surge on the hot and neutral lines. But: (a) that's not a likely occurrence, since neutral and ground are tied together at your building's breaker box; (b) unless your electronics have some connection to ground, or ground-referenced wire, other than their power cord, a common mode surge won't hurt them or affect them anyway.
posted by hattifattener at 11:54 AM on July 30

I'm not an electrician, nor have much of an understandning of it, but was told by one that installing a 'GFI' outlet in place of the ungrounded one would get me 'up to code' if I wanted to plug in grounded appliances. (Ontario/Canada)

Though, now that I think about it (and have completed it), I'm not sure if 'up to code' means proper safety, or just 'made government / insurance co. happy'...
posted by csmason at 12:29 PM on July 30

A GFCI is up to code in that it will protect you if you drop a hair dryer in a bathtub but it still lacks a proper ground which is needed for a surge protector. I got corrected on this in an AskMe thread just a few weeks back.
posted by GuyZero at 12:49 PM on July 30

I thing GuyZero is right. I also suspect surge protectors, the ones you buy in the store as a Regular Joe(tm) don't do anything to protect your computer hardware. UPSes might. I think brown outs or interrupts are more likely to screw up your computer than momentary over voltage spikes.
posted by chairface at 1:24 PM on July 30

chairface, guyzero: A schematic of an actual suppressor (first one Google gave me). But like I said, they vary a lot.

Unless you know what kind of bad power you have and know that a given surge suppressor will actually help with it, they're probably not worth the bother.

Grounded outlets, on the other hand, are a very good idea.
posted by hattifattener at 5:54 PM on July 30

hattifattener's answers are right on the money.

That How Stuff Works article is okay, but there is a lot of misinformation..

You should definitely use a surge protector with your computer. It is filled with voltage-sensitive components that a power surge could damage very easily. At the least, this damage will shorten the life of your computer, and it could very easily wipe out all of your saved data or destroy your system. Computers are very expensive items, and the data they hold is often irreplaceable, so it's only good economic sense to invest in a quality surge protector.

That's ridiculous! First of all, the power supply has some, and sometimes a lot, of surge suppression capability built in. Second, a surge might destroy the power supply, but it is very unlikely to get past the power supply to have any effect at all on the rest of the computer. Also, "shorten the life of your computer"?!?!?! This reveals a complete misunderstanding of how semiconductors work.
posted by Chuckles at 8:03 PM on July 30