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Blu October 12, 2012 08:54 PM

UPS question
I've had a UPS for about a year now that I haven't put to use. I know what it is and all but was a little on the ropes with this question. I currently use a power surge enclosed bar (belkin I believe, pretty much tries to hide cabling) When using the UPS can I just plug my extension cord (only have one outlet in the room, behind the bed) that usually goes to the surge protector on it then plug the surge protector straight into the UPS without having to re wire everything? I mainly want to do this because in my area we've had alot of power problems. Some days the power will work ten minutes then go out for five and repeat for a couple hours. Just sorta want to avoid having to restart with a short power outage. I know I probably explained this in a hard to understand manner but I'll do a illustration.

Wall > Extension cord > UPS > Surge protector

Would it work?

Would that work?

Perineum October 13, 2012 12:12 AM

If I recall correctly UPS do not like having surge protectors behind them. If you went with a simple octopus plug it would work but anything with surge protection is going to cause problems.

Also, it had better be a big UPS to handle multiple plugs for 5 minutes at a time.

Mine is only a 700VA UPS but it'll run my server for over 3 hours if need be.

KaptCrunch October 13, 2012 10:46 AM

Wall > Extension cord[12awg] > UPS > computers etc

Peri correct

Using surge strips with APC's Back-UPS and Smart-UPS products.

Schneider Electric recommends against the use of any surge protector, power strip or extension cord being plugged into the output of any APC Back-UPS and Smart-UPS products. This document will explain why.

Plugging a surge protector into your UPS:
The noise filtration circuitry in a Surge Protector can effectively "mask" some of the load from the UPS, causing the UPS to report a lower percentage of attached load than there actually is. This can cause a user to inadvertently overload their UPS. When the UPS switches to battery, it may be unable to support the equipment attached, causing a dropped load.

Surge protectors filter the power for surges and offer EMI/RFI filtering but do not efficiently distribute the power, meaning that some equipment may be deprived of the necessary amperage it requires to run properly causing your attached equipment (computer, monitor, etc) to shutdown or reboot. If you need to supply additional receptacles on the output of your UPS, we recommend using Power Distribution Units (PDU's). PDUs evenly distribute the amperage among the outlets, while the UPS will filter the power and provide surge protection. PDUs use and distribute the available amperage more efficiently, allowing your equipment to receive the best available power to maintain operation.

Plugging your UPS into a surge protector:
In order for your UPS to get the best power available, you should plug your UPS directly into the wall receptacle. Plugging your UPS into a surge protector may cause the UPS to go to battery often when it normally should remain online. This is because other, more powerful equipment may draw necessary voltage away from the UPS which it requires to remain online. In addition, it may compromise the ground connection which the UPS needs in order to provide adequate surge protection. All APC Back-UPS and Smart-UPS products provide proper surge suppression for power lines without the need of additional protection.

Maintaining EPP and Warranty:
Plugging any non-APC surge protector, power strip, or extension cord into the output of an APC brand UPS could void your Equipment Protection Policy (EPP). However, the standard 3 year product warranty is maintained. If, after taking into consideration this knowledge base document, you choose to use an APC brand surge protector in conjunction with your APC brand UPS, your warranty and Equipment Protection Policy will be maintained.

Blu October 13, 2012 11:40 AM

Thanks peri and kapt. I do also have somewhat of a dumb question about externals and power. I currently have 9 externals connected to the pc and for there power I just have these 4 port little bars that have power plugs placed so block power plugs can be connected and not loose the outlet. Think this would be ok to put on a extension cord coming from the other room? I looked it up and they seem to only use about 10-15w per drive but just wanted to be sure.

Edit: Just checked the one I have, it's 1000VA, I believe it's this one,
Cyberpower CP1000AVRLCD 1000VA 600W UPS 9 Outlet 1080 Joules AVR LCD RJ11/RJ45 & 1 USB Serial Black

Perineum October 13, 2012 01:46 PM

If you are just powering the drives and computer with that then I'd say you'd get your 5 minutes..... providing there is enough time between outages to recharge your battery.....

westom October 14, 2012 07:14 AM


Originally Posted by Blu (Post 661814)
Wall > Extension cord > UPS > Surge protector
Would it work?

They don't like to talk about it since the reality will undermine popular myths. Some of the 'dirtiest' electricity an appliance might see comes from a UPS in battery backup mode. For example, this 120 volt UPS outputs 200 volt square waves with a spike of up to 270 volts. Ideal power for any electronic appliance. But potentially harmful to small electric motors and power strip protectors.

They will say why with numerours irrelevant comments. But the bottom line: that above sine wave output UPS is that 'dirty'; that potentially harmful to the protector.

NyteOwl October 14, 2012 09:47 AM

Not all UPS output square wave to the items they power. While the raw inverter output is indeed a square wave, better units use shaping circuits to provide an almost sine wave output virtually all electrical appliances can handle. As with most things, you get what you pay for.

westom October 14, 2012 10:03 AM


Originally Posted by NyteOwl (Post 662227)
Not all UPS output square wave to the items they power. While the raw inverter output is indeed a square wave, better units use shaping circuits to provide an almost sine wave output virtually all electrical appliances can handle.

A square wave is power that virtually all electornic appliances can handle. Electronics are required to be and are designed that robust. A shaping circuit still leaves most UPS outputs looking like a trapezoid with spikes - as in pictures below.

That square wave output is also called a pure sine wave. How pure? Only useful recommendation says how 'pure' with numbers such as %THD. Why do so few discuss %THD? The manufacturer often will not publish those numbers. Otherwise many would learn their 'pure sine wave' output was only square waves.

Due to how electornics are designed, then the 'dirtiest' UPS output is also ideal power. Meanwhile, UPS manufacturers only say to not power a power strip from that UPS. They never really say why. But these pictures (Tech Tip 03 from an AC utility) of a UPS output does:
Tech Tip 03 - Indiana Business-Duke Energy

Another posted the output from his sine wave UPS:

Ideal power for any electronics. But can also damage strip protectors.

How much for a truly pure sine wave UPS. On the order of $1000. So that one can use a $90 power strip? Better is to use the $7 non-protector power strip.

NyteOwl October 14, 2012 11:59 AM

Well, I put my APC UPS on an oscilloscope and the output is a sine wave, not a square wave - and it didn't cost close to $1000. I do have a cheaper model and even it is a stepped sinusoidal approximation rather than a simple square wave. YMMV. And most electric motors do not like square wave signals. Square wave is 100% duty cycle with generally results in overheating motor windings

westom October 14, 2012 07:11 PM


Originally Posted by NyteOwl (Post 662283)
Well, I put my APC UPS on an oscilloscope and the output is a sine wave, not a square wave - and it didn't cost close to $1000.

Sound like you got a good deal. What manufacturer and model?

Of course, if that UPS does output a pure sine wave, then the manufacturer would waste no effort defining it with a number. So what was its %THD in its specs? Maybe 2%?

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