Will a UPS Work Properly on an Ungrounded (2-wire) Circuit

Discussion in 'hardware' started by Aaron Here, Oct 12, 2008.

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  1. Aaron Here

    Aaron Here Registered Member

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    I would like to buy and use a UPS for the PC in my home-office, but the electrical wiring in my old home is not grounded (it's a 2-wire circuit and a ground-tester does not show a ground on any outlet)!

    I've been told that a properly grounded electrical circuit is required for a UPS to detect the power-drop and take-over in a timely manner. I would appreciate knowledgeable feedback as to whether or not a UPS will work properly in my home environment. :doubt:
     
  2. Peter2150

    Peter2150 Global Moderator

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    I also am in an old building. The circuit testers on my APC Backups 1500's glow red indicating same thing you have, and yes they do work.

    Pete
     
  3. Rmus

    Rmus Exploit Analyst

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    A couple of years ago, I asked the same question and received conflicting answers. Soon thereafter, I installed a Belkin 1500 joules power strip and one indicator light stayed dark because of no 3rd ground wire, so I decided to have a new circuit pulled to my home-office room.

    ---
     
  4. Aaron Here

    Aaron Here Registered Member

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    Pete, have you actually proven that by yanking the PC's power cord and have the UPS take-over without interruption?
     
  5. Aaron Here

    Aaron Here Registered Member

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    I've had quotes from 3 electricians - all 3 bids were well in excess of $1K to do just that. That's unaffordable for me at this time.
     
  6. JRViejo

    JRViejo Global Moderator

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    Have you thought about installing a Ground Fault Interrupter outlet? Finding an electrician to do it might be another story.
     
  7. Aaron Here

    Aaron Here Registered Member

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    I don't see how a GFI-outlet has anything to do with what I'm asking. :doubt:
     
  8. Dark Shadow

    Dark Shadow Registered Member

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  9. Arup

    Arup Guest

    Ground is needed for the surge protection in the UPS as far as I know.
     
  10. Peter2150

    Peter2150 Global Moderator

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    Haven't had to. I'll be sitting here and my A/C unit slows for a minute, and then comes back. All three UPS units switch.

    Pete
     
  11. Peter2150

    Peter2150 Global Moderator

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    I don't rely on the UPS for surge protection. I have a Zero Surge unit in front of them.
     
  12. Arup

    Arup Guest


    Thats the best way, unfortunately in India, you can't find them, not even the APC surge protectors and have to rely on the one built in to the APC UPS.
     
  13. Aaron Here

    Aaron Here Registered Member

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    Pete, I take it you are speaking of occaisions when you have experience an actual power outage?


    Pete, I would be very interested in learning how a Zero Surge unit can do the job in an ungrounded AC environment (like yours and mine)! o_O

    Thanks,
    Aaron
     
  14. Peter2150

    Peter2150 Global Moderator

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    Hi Aaron

    I can't begin to give you a technical answer, as I honestly don't know, but I just know that given the screwy power situation here at times, since I went to the setup of the Zero Surge units followed by the APC Backups 1500's I haven't had anymore issues.

    Pete
     
  15. appster

    appster Registered Member

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    Aaron, the answer is Yes, BUT the built-in surge protection in almost all UPS units will not work, as they all work by shunting electrical surges to ground (and you apparently don't have an earth ground). Furthermore, when you plug the UPS in your ungrounded AC line it will likely have an LED that will glow indicating the absence of a ground and any 'insurance-policy' offered by the UPS manufacturer will not be honored because of that.

    Solution: Going to your fuse or circuit-breaker box, you could find and open the circuit to the outlet supplying your PC and monitor. You could then replace the 2-prong outlet with a 3-prong outlet, adding an insulated copper (heavy guage) wire to the ground (3rd) connector. Then route that wire to the closest cold-water pipe and clamp the wire to that pipe (you can buy a clamp for this specific purpose at Home Depot or the like). An alternative (but somewhat more difficult) solution is to clamp that wire to a grounding-rod that you drive several feet into the ground outside your house. Either method will provide the missing earth ground, eliminating the fundamental problem from the AC-line supplying your PC.

    If you feel uneasy or uncertain about doing the above yourself, call an eletrician or handyman; this job should not be expensive!
     
    Last edited: Oct 16, 2008
  16. OLDXTECH

    OLDXTECH Registered Member

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    Re adding a ground line to earth-

    In some really OLD systems, there was NO ground at the Service Panel where the fuse or circuit breaker is located. This is a potential danger. In addition to connecting an earth ground at the cpu/ups plug, an additional ground should be added to the case of the Service Panel and bonded to the neutral [as in 3 wire drops from the main line]. If you don't understand this, then get an electrician to do it! This will not have anything to do with the operation of the ups/gfi at the cpu, but will be safer in case of REALLY excess voltage dropping down to the Service Panel from the main lines. I know the hard way - almost fried my whole house years ago!!! It would also be a good idea to ASK the UPS mfg for the unit in question.

    Cheers. Jim
     
  17. cortez

    cortez Registered Member

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    If you have a metal based conduit ( or BX ) system with metal boxes a grounding adapter will be just as good as an a three prong outlet (make sure the screw is nice and tight). Most hardware stores have them the look like this: http://www.radioshack.com/sm-3-prong-grounding-adapter-2-pack--pi-2104010.html

    If you have a metal system replacing the 2 pronged outlet with a three pronged outlet is not too difficult and it instantly grounds your system as long as you correctly re-screw the outlet back into the box and make sure that the screws are nice and tight. Turn off the electricity to the outlet before attempting this.

    The one warning is to watch out for old wires that may shed their cloth/asbestos insulation when working on them (hot shrink tubing is the usual remedy for this problem).

    If in doubt an electrician is called for ( the average cost in my area is 65 to 95 dollars an hour for licensed electricians and about 30 to 50 dollars for an hour for unlicensed ones.

    A handy man is the cheapest way to go and many are well qualified for adding outlets or entire lines, ( as a contractor I do my own electrical work but do occasionally hire out to subs and sometimes to "handymen" [many are moonlighting factory maintenance men with multiple talents]). A recommendation is called for on handy men as well as electricians (many electricians prefer to replace everything rather to repair as they can charge much more).

    If you get 3 estimates expect 50% difference in prices. If you get 6 estimates you can expect 100% difference in prices.

    There are of course other ways to ground your system but it all depend on your type of dwelling: A house is easy and a multi story apartment is a different matter altogether. Many of these remedies are out of code ( and thus "illegal" ) but that has not stopped untold numbers of people from using these remedies.

    If you are going to add a copper rod for grounding it should go into the ground with only a few inches above ground (get them at Home Depot or a hardware store) in good conducting soil. See http://www.acehardware.com/sm-grounding-rods--fi-1303010_cp-2568454.2632222.html

    Some experts maintain that more than one ground ( in different locations) for a dwelling can cause fires as it allows for the insulation of a wire to melt and cause sparking and melting the conductor before blowing a fuse/breaker (the "phantom ground" theory is used to explain unexpected/unknown reasons for fuse/breaker "failures").

    I have seen this happen on a dwellings with only one ground at the service entry location. As you can see there is a reason why it is called electrical theory.
     
    Last edited: Oct 18, 2008
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