Best solution for clean power to PC with only 2 prong outlets

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sdhaku

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I live in an older apartment with only 2 prong outlets. I'm also in southern California so there's little chance of lose of power due to weather. What I'm really looking for is a way to provide clean power to my PC and other equipment. I did buy a nice UPS but from what I've read without a ground it's pretty much a decoration.

What would you guys advise? Should I push my landlord for 3 prong outlets with grounds? Not sure on the odds of success with that option. Are there other devices that are better suited for my scenario? Thanks!
 
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Adding a ground does not improve the quality of your power - your existing installation already technically has a ground through the neutral wire. The reason for the third wire ground is safety: provide an independent path to ground for safety-critical stuff like chassis ground in case the neutral wire goes open or gets miswired to live.

With many SMPS having surge and noise suppression between live, neutral and ground, not having a ground wire may translate to your PC's chassis and other equipment with exposed chassis ground to become live at ~60V, which could get annoying and potentially dangerous if those Y-caps or line-ground MOVs fail shorted.

So, from a safety standpoint, I would highly recommend having the apartment re-wired...
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Titan
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May 18, 2007
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Adding a ground does not improve the quality of your power - your existing installation already technically has a ground through the neutral wire. The reason for the third wire ground is safety: provide an independent path to ground for safety-critical stuff like chassis ground in case the neutral wire goes open or gets miswired to live.

With many SMPS having surge and noise suppression between live, neutral and ground, not having a ground wire may translate to your PC's chassis and other equipment with exposed chassis ground to become live at ~60V, which could get annoying and potentially dangerous if those Y-caps or line-ground MOVs fail shorted.

So, from a safety standpoint, I would highly recommend having the apartment re-wired with proper ground. It may also reduce you and your landlord's insurance premium.
 
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gondo

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I'm an electrician. You can't add a 3 prong plug cause you only have 2 wires in the wall. No bond (ground) wire. What you need to do is install a GFI receptacle. $15 and you are good to go. The GFI will work without a bond (ground) and will protect you.

Next use the UPS. The UPS may give you an error that there is no bond but ignore that. At least the circuit is protected through the GFI.

In old houses without 3 prong plugs you install a GFI on the first device of each circuit after the panel and it protects all receptacles on that circuit. Some insurance companies will accept this, others will required a complete overhaul to 3 prong plugs throughout with new wiring.

 
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sdhaku

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I called CyberPower today and spoke to a support person there. They basically said a GFI would not work nor would a 3 to 2 prong adapter. They said the only way for me to be protected would be to have a grounded outlet. More importantly he said the device is not really for power conditioning which is really what I'm looking for.

I spoke to my landlord and it sounds like him might try to help me out by installing a few grounded 3 prong outlets.
 
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gondo

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A UPS is exactly power conditioning. Your computer runs off the battery 100% of the time and when plugged in it remains charged. You always have 100% clean power, a perfect 120V AC sine wave. When the power goes out you have 5-20 min of backup.

But you can't plug the UPS in because you have no 3 prong. The right way to do that is with a GFI. Use the 2 wires on the GFI and ignore the ground wire. A GFI will work without a ground, and the UPS will provide the conditioning and backup you want. $15 for a GFI is all you want.

The only problem you can encounter, is if the UPS has some intelligent circuit that detects no voltage between hot to ground. It may not operate and auto shut down since it doesn't detect the ground. This would only occur because of the design of the UPS.
 
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Titan
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That's not how a typical UPS works. Consumer units under $300 or so are "line-interactive" UPS that provide little to no line filtering and connect the loads directly to line voltage under normal circumstances. During moderate sags and swells, many units have an AVR transformer that will either buck or boost the line voltage by about 10% to bring it closer to nominal. When line voltage is excessively noisy or out of spec, the UPS switches to battery power which may be one of a handful of different types of waveforms, usually a bipolar square wave with some dead-time in budget-friendly units or a PWM approximation for higher quality units.

The only type of UPS that provides full line conditioning is online UPS, aka double-conversion UPS, and those are typically too expensive for the average consumer at over $500 for 1kVA. To that initial cost, you also need to add the 5-10% of additional power and cooling costs due to double-conversion losses.
 
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sdhaku

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Good news even though my outlets are 2 prong there is a line that runs back to the breaker so they are grounded so all that's needed is to swap for 3 prong outlets!
 
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