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PC plugged into an outlet with no ground...

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July 23, 2009 7:42:52 PM

Hi,

I feel like I should preface this with the fact that, while I don't think this is the right forum for this post, I couldn't find a better section on the site. Similarly, I know of no other sites for competent computer discussion.

Anyway, a bit ago I built myself a $500 PC from new components (I can supply a list if it matters). Recently I have moved, and through carelessness (much carelessness) I neglected to check that not one outlet in this apartment has a ground (I've become so accustomed to the ubiquity of 3-prong grounded outlets that it never crossed my mind). To my dismay, after having tested each outlet with a neon tester, none have the ground wire available. The cost to rewire some of the outlets is at least $1000 from what I understand (this is a very rough figure, the idea is, it will cost more than my PC).

I have yet to plug my computer in out of fear. I understand that a surge protector is a must, but what else might occur without a ground? Is there a safe, legal way I can avoid some of the negative effects of not having a ground? I am not particularly knowledgeable on the topic, and I haven't been able to gather any concrete facts about this problem from Google. My fear is not as much surges as these can be controlled. For some reason I have this idea that a PC will build up static/excess electricity that it needs to discharge. Really I have no idea what is true about the situation though, which is why I've come to this community for help.

Thanks much,
Ryan

More about : plugged outlet ground

July 23, 2009 8:00:32 PM

$1000 bucks to wire a ground? o.0

connect a wire to some copper pipe, bam, grounded.
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July 23, 2009 8:11:06 PM

neon neophyte said:
$1000 bucks to wire a ground? o.0

connect a wire to some copper pipe, bam, grounded.


Phhh... if electricity was so easy, we wouldn't need engineer to design the electrical building circuitry.

I am sorry... but if a surge happens, I cannot guarantee the outcome... as an electrical engineer...

The owner of the building absolutely needs to redo the electricity. If he can't, he should take down the whole place.

Still, you should probably found another apartment... seriously. I would not risk 5000$ of electronics knowing the electricity is as old as WWII.
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July 23, 2009 8:25:04 PM

redgarl said:
risk 5000$ of electronics knowing the electricity is as old as WWII.


Well it's $500, not $5000 thankfully. I will definitely have to try to be more assertive about getting some legitimate wiring run through the place. That seems like the only viable option. On the outside wall of the back of the apartment there is a grounded outlet, so I know the box has a ground, which is uplifting. Of course the only grounded outlet had to be inaccessible...

I understand the problem with surges, but still I wonder what other issues arise from lack of a grounding outlet.

Thanks very much for the replies,
Ryan
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a b B Homebuilt system
July 24, 2009 3:46:11 AM

If I'm not mistaken though, even on 2 prong outlets, one prong is positive, one negative, I think the negative essentially works like a ground. If you are concerned, consider purchasing a UPS, aka battery backup. That should help even out voltage spikes t your rig.
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a b B Homebuilt system
July 24, 2009 3:59:37 AM

Unfortunately if the apartment building is old enough to have no grounds in the outlets it likely never even had grounds run to the outlets and may even be old aluminum wire which would require a rewire of the entire building. There is no safe way to simulate a ground unfortunately.

i agree with the suggestion of the battery backup as your best option as a surge suppressor, if you get one that goes AC-DC-AC it will even out some of the voltage spikes but if you get a power surge you will have a 5 pound lead acid battery exploding in your room so thats not too good either.

Talk to the town or city you are in and find out the rules regarding wiring in rented buildings, many will require the landlord to cover the expense to bring it up to code.
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a b B Homebuilt system
July 24, 2009 4:06:17 AM

110 works like this, one of the plugs is hot, 110 volts.
The other is called the common, or ground, and is grounded at the power company.
The third, is an extra safety measure in case of improper wiring, and it is the round ground plug, this is physically grounded at your house. It literally is like someone said already...attach a third wire, hook it to a copper pipe and stick it in the ground.
You can buy an adapter that will allow you to connect a ground wire to the screw in the center of the face plate. Of course that will do nothing if the box it's self is not grounded. But, at least you can plug it in. Although the electric in your building is not up to current code, I would put a good surge protector on the plug in, and not worry about it too much.
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a c 84 B Homebuilt system
July 24, 2009 4:20:01 AM

A ups will test for being plugged into a grounded outlet, and complain bitterly if one is not supplied. Two wires were common some years ago. It is unsafe only if the equipment attached to it fails in a bad way.

If you can't get the apartment to fix their problem, then you can try to jury rig a remedy yourself.
My suggestion is to buy a 3 prong outlet and a spool of green insulated ground wire. Wire one end to the ground on the outlet and the other to a cold water pipe or a metal radiator.
Then test with your tester.
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July 24, 2009 3:02:47 PM

geo, im glad im not the only makeshift electrician in the bunch here. ^^
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a b B Homebuilt system
July 24, 2009 4:29:08 PM

You have several issues to deal with here, starting from the apparent situation that there is no reliable Ground anywhere in your new apartment. A Ground is used for two purposes: part of a protection system for wiring or circuit faults that mistakenly send real power to the computer's chassis that is accessible to people; and removing static charges and electrical signal noise while they are at low levels, before they build up to troublesome.

1. Assume you have no Ground anywhere. Even the one three-prong outlet you have MAY have been especially installed properly, but quite possibly not. It's an old and BAD habit to replace a two-prong outlet on an ungrounded system with a three-prong one just to allow using that kind of plug, but NOT actually provide any Ground connection! So unless you can verify that the 3-prong one is done correctly, assume it is not.

2. Here is how 110 VAC house wiring in Canada and USA (and others) is supposed to be set up. It's based on what is called a Grounded Neutral system. Both at the transformer out on the power pole, and at the fuse or breaker box in the house, the Neutral line is connected to a true Ground to the earth. So at those two points the Neutral line is at zero volts potential compared to the earth. Anywhere else in the house the Neutral line is NOT guaranteed to be the same as ground. It is carrying current supplied to the user's device (a computer or a tea kettle) back to the Neutral bus in the fuse box. Since the wiring in the wall has a very small but non-zero resistance, there actually is a small voltage present at the wall outlet on the Neutral line, compared to true Ground.

3. At the house fuse box or breaker panel there is a true Ground connection to the panel box itself. As I said, that also is connected to the Neutral bus in the box. In modeern designs there is a separate Ground bus in the box, and all wiring running out to circuits everywhere in the house is done with cable containing two current-carrying conductors (insulated) plus one bare copper wire for Ground. This is how Ground is provided at every outlet box in the house. And in all of these, NOTHING (except a Ground lead) should be connected to that Ground, so it never carries any current under normal circumstances. In older systems there was no Ground lead extending beyond the main fuse box, and no Ground bus in the box.

4. Today's design with 3-prong outlets etc. has a cable coming into a box in the wall with three wires (although the wire is labeled something like 14/2, indicating that it has 14-gauge wire in it and has two current-carrying insulated wires, PLUS a bare Ground wire). The color code is: black for Hot (the "supply" of power), White for Neutral (for returning current) and bare for Ground. When a 3-prong outlet is mounted in the wall box so the round hole is at the bottom of a triangle of holes pointing down, then the round (bottom) one is Ground, the left one with the wider slot is Neutral, and the right one is Hot. That way you cannot plug even a 2-prong proper "Polarized" plug in wrong, because the wider (Neutral) blade won't fit into the narrow (Hot) slot. In older non-grounded systems, there is no Ground, but there still are Hot and Neutral. However, often these sockets were made with no difference in slot widths, and there was no standardization on whether Hot was left or right. In a modern system if you use a neon tester you will find 110 VAC from Hot (right) to Neutral (left), and also 110 VAC from Hot to Ground, but no apparent voltage from Neutral to Ground. That is because the tester cannot show you very small voltages between Neutral and Ground. In an older ungrounded system, you'll still detect 110 VAC from Hot to Neutral, but there appears to be no voltage from either of those slots to the metal box in the wall. That is because the metal box is not connected to anything! There is no Ground available at the box.

5. Now to start on solutions, other than moving or persuading the landlord to re-wire the place. For the purposes of getting rid of low-level voltages, either static charges or electrical noise signals, you can try to connect a separate (green) wire from the computer outside case to a reliable Ground. Best place to look is a water pipe. Water supply systems run a pipe though a lot of soil, thus providing good electrical contact to the earth. Older systems are ALL metal piping, so it works. However, some have been modified with plastic piping components in odd places, so it is always possible that a water tap may NOT be a reliable Ground, and it is nearly impossible for an amateur to tell. But that's still your best bet.

6. The other function of a good Ground is in electrical supply system safety. One way a Grounded system protects you is that any part of your appliance that is exposed to people should be connected to true Ground. Then if anything goes wrong in the appliance and the Hot supply comes into contact with that exterior, the Ground lead does two things. The most important is that it provides a high-current-capacity route for the power to be taken to Ground - so high that the current will exceed the limit of the fuse or Breaker in the panel that supplies the Hot lead, and it will blow out. That stops the current. The second is that, during the very short time all that takes, the exterior case you can touch will be VERY close to zero volts anyway, so you are unlikely to be shocked. Now, if you install a green grounding wire to a nearby water tap, it may or may not be able to carry all that current and provide the protection a real Ground system can - it depends on how good the substitute ground connection is. But it should be able to handle the small currents from electrical noise and static charges IF it is actually connected to the earth.

7. An alternative to a true Ground system for safety is a Ground Fault Circuit Interrupter (GFCI). You can actually buy the simpler one-circuit version of these at any electrical supplies or hardware shop. They look a lot like a normal 3-prong double outlet (but more expensive) and you mount them into the wall box in place of the old outlet device. (Obviously, before starting you MUST isolate power from the box before opening, by removing the fuse or shutting off the breaker that supplies this outlet box.) They are different on the front in that they also have a little indicator light, a TEST button, and a RESET button. If you don't understand house wiring you are best advised to have this item installed by someone who does, like an electrician. Once properly installed, what they do is to constantly measure and compare the currents flowing in both the Hot and Neutral parts of the circuit. Those ALWAYS should match. If they don't the GFCI interprets that to mean some current is leaking out of the circuit to somewhere else, and that could be a big problem. So it shuts off the power or "trips out", just like a circuit breaker does. Once you fix the original problem, you use the Reset button. You can test at any time with the Test button, and it will trip out for you. The intriguing part is that this device does not need a true Ground point to operate, so it can work in an ungrounded outlet box. It just uses a different measurement to decide when to shut off power. So it provides very similar safety protection for people and for many appliance malfunctions, but it does nothing for getting rid of electrical noise and static charges.

So, a combination of a GFCI for safety protection against malfunctions, and a ground wire from the computer's case to a water line for removing static charges and electrical noise, may work for you. These still do nothing for power system surges, but a modern grounded system does not, either. That's a whole separate issue.
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a c 113 B Homebuilt system
July 24, 2009 8:07:30 PM

That's really nice Paperdoc. Thanks for taking the time on this. Would you copy this (using the BBCode link at the top of the post or by editing) and make a new post here?:

http://www.tomshardware.com/forum/forum-28-175.html

Title it something like "What to do about poor or no electrical ground" (just something like that) and then PM me with a link to it? I'll include it in my troubleshooting guide and send it along to shortstuff to link in his new build won't post checklist.

That way we can preserve your hard work ;) 
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a b B Homebuilt system
July 25, 2009 1:41:51 PM

Far more information than the average person will ever use, or even need to care about, but a good detailed post non-the-less.
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July 26, 2009 7:49:23 PM

Thank you Paperdoc. As the two before me have said, your post was very helpful. I am especially thankful for your treatment of the problems outside of power surges.

I have a followup question. As others have previously recommended this in their replies, if I were to use a 2 prong to 3 prong adapter with a ground tab (such as this), and attached a wire from the screw to a water pipe, would this provide the same protection, or would I be better off running a wire from the case to the water pipes. The reason I ask is, I would like to use a surge protector strip to power everything for the computer. If I could ground it at the outlet like that, to me at least, that seems preferable.

Again, thank you so much,
Ryan
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a b B Homebuilt system
July 27, 2009 6:42:30 PM

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a b B Homebuilt system
July 27, 2009 7:11:04 PM

measure said:
Thank you Paperdoc. As the two before me have said, your post was very helpful. I am especially thankful for your treatment of the problems outside of power surges.

I have a followup question. As others have previously recommended this in their replies, if I were to use a 2 prong to 3 prong adapter with a ground tab (such as this), and attached a wire from the screw to a water pipe, would this provide the same protection, or would I be better off running a wire from the case to the water pipes. The reason I ask is, I would like to use a surge protector strip to power everything for the computer. If I could ground it at the outlet like that, to me at least, that seems preferable.

Again, thank you so much,
Ryan


Yo have the right idea. 2-to-3-prong adapters are potential trouble because you can't rely on whether or not the metal box in the wall is properly Grounded. But you understand this and propose to provide a good Ground connection. A nearby water tap or pipe is tempting and often quite suitable, but hard to verify. I'd have more confidence in a dedicated wire (usually only one wire, at least 14 gauge or 12, with green insulating covering) run all the way down to where the fuse box or breaker panel is. At that panel there should be a heavy wire coming out of the part where the main shut-off switch is and going to a nearby water pipe (or, maybe to a dedicated Ground cable that runs outside the house and into the ground). Usually there's a kind of 2-piece metal "saddle" fitting on the pipe with a place for the Ground cable to connect in. You can loosen off the cable connection and work your own new lead into it, then tighten up again. Or, you can buy another saddle fitting and some sandpaper, polish the pipe clean just above the existing fitting, and mount the new saddle right beside the existing one, then connect your wire to that. Either way you have made a solid connection to a (presumably) reliable Ground source, which may be better than a water tap 2 floors higher up in the building. However, I realize that it may be extremely difficult to run your new green wire down to the known Ground. If you can't, I'd still recommend the saddle device as the way to attach your new Ground lead to whatever water pipe you use.

By the way, if you look closely at a typical double 3-prong outlet device that you mount in the wall box, you can see that the metal frame of it (that holds its mounting screws to fasten it into the box) is connected to the Ground terminal, too. So once the device is mounted in the box, then the Ground Terminal, the device frame, and the box itself all are connected together as Ground. And that also includes the metal screw in the center that holds the box cover in place, which is why that screw sometimes is used as a Ground point. So, you could establish your new Ground lead from whatever source and mount a new 3-prong outlet in the box, using the Ground terminal of the double-outlet device as the attachment point for your ground lead. This is the proper way to provide a truly Grounded 3-prong outlet update for an old 2-prong ungrounded box.
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August 11, 2012 3:24:45 PM

paperdoc, if i want to ground my pc, and have 3 pin socket but not grounded room, can i connect my pc case with socket earth outlet? Will that work?
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!