How to Properly Add Outlets to a UPS

I have seen alot of people plugging in surge strips to UPS's in order to add plugs for additional hardware (I have been guilty of this in the past as well). The act of adding outlets to a large battery backup (1500w) for small devices is perfectly acceptable but you should not use surge strips. I decided to do some research on the subject and it seems APC has answered this question in one of their articles. They specifically recommend using some type of PDU (Power Distribution Unit) to add outlets to a UPS. A PDU does not have surge protection or filtering but it does make sure each plug gets a balanced amount of power. APC and several other manufactures specifically recommend against plugging in surge strips to UPS's (see article below for reasoning). I just purchased two of the AP9562 PDU's for my APC 1500XS UPS. Now I will have enough room to plug in all those damn wall warts (ProCurve Switch, SnapGear VPN, Linksys Cable Modem, Linksys Wireless Access Point, etc.) Just thought I would post this if anyone ever has the same question or worry.


http://emea-en.apc.com/app/answers/detail/a_id/1372/~/using-surge-strips-with-apc's-back-ups-and-smart-ups-products.

"APC 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: 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.

However, please note that the UPS is designed to handle a limited amount of equipment. Please be cautious about plugging too much equipment into the UPS to avoid an overload condition. To understand the load limit of your particular model UPS please consult the User's Manual, or visit APC's Product Page at www.apcc.com/products.

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.

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.

If you have any additional questions regarding your set-up, please call APC technical support at 800-800-4272 (Mon-Fr 8am-8pm EST)."

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.

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This is hogwash. Odd that APC is spewing this crap. A surge protector is going to have some EMI filtering at one and then a power bar of some sort that all outlets plug into... all outlets are going to be effectively the same.



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Yes you need to be careful of overloading your UPS.

A crappy simulated sinewave surge protector may act really weird, unexpected behavior due to how the EMI filtering reacts to the unusual waveform.

How does a PDU distribute amperage more efficiently or more evenly than a plain power strip made of 3 heavy brass strips with the AC outlet socket connections stamped right into them?

I'd just use an ordinary power strip and be careful not to overload any of its outlets or the UPS outlet it's plugged into.

I've been looking for related info and could not find ANYTHING approving these last two comments above.

does anyone have any knowledge / experience for a plain power strip made of ~3 connecting to a battery-backed outlets of APC UPS PRO 1500?

is it a real safety hazard or could immensely quicken the degradation of battery? even if I'm not exceeding overall watt/power available for backing-up?

None of my equipment has cared about power strips off battery backups.

I'm not saying it's the "Right" way, but I haven't had any problems doing it... like was said, don't over load it though.

thnx for sharing, ToddW2.
one answer is quite better than none. much appreciated.

surely I'm not planning on overloading the battery which would simply lead to a failure.
it's just that I'd prefer additional 2x monitors hanging on a battery-backup. and I have like ~400 watt extra with my current setup (obviously, it would not hurt powering those).

going to risk it.
if anyone has any thoughts with experience on this, please share. I bet this info would help some others too.

I have been running my modem and router off an extension cord with a few extra outlets at the end connected to my UPS for a few years now. No issues as I am under the power limit and those use less than 50W total. I did this since I didn't have the cable length and was one outlet short.

Just buy a non-surge protecting power strip then. This is what I do. I have my main 900W UPS and I have 2 power strips with no surge protection plugged into it. If you open up one of these power strips, it's basically just a bus bar connecting everything in parallel.

http://www.newegg.com/Product/Produ...&cm_mmc=TEMC-RMA-Approvel-_-Content-_-text-_-

is the one I have. Made of metal, has a flip door to protect the power switch from accidentally getting pressed.

Good stuff. One is running all my monitors and sound system. The other is powering my desktop and watercooling pumps.

All outlets on a UPS that are on the battery backup (not all are, some are just surge protected) are on a common bus. So there is no method for the UPS to determine that one outlet can get more power than another.

Overloading a UPS won't hurt the battery. It will cause your UPS to get less run-time, for sure. That being said, you absolutely can overload a UPS - the inverter (the piece of electronics that takes the battery and turns it into an AC waveform of some sort) will get overloaded. Most UPSes will just shut down, rather than overload and damage (much like a computer power supply, if overloaded they will just shut down rather than damage themselves).

Battery determines run-time. The inverter determines the methods of protection (surge, low voltage correction, waveform shape, etc) and how much load you can put on it (usually measured in VA, which is typically a bit higher than the Watts rating by around a factor 1.25 or so). The number of outlets - regardless of if they are built into the UPS or added on via a PDU or power strip - only really determines how many things you can plug it. It does absolutely nothing to say how much power you can pull through a plug, how much power is delivered to each plug, the filtering or protection available on each plug, or anything else. Just strictly the number of plugs you can fit into the device.

The reason UPS manufacturers recommend you don't use a power strip is two-fold. First, it is because it makes it that much easier to overload a UPS, especially if you plan on plugging in 3 computers, a toaster, a hair dryer, and various other random high-power devices. Second, it's because they can use the lack of outlets to upsell models (or add-on components) to you. There is no good technical reason to not use a basic power strip, as long as you realize that adding in more outlets does not change the capacity of the inverter or the battery.

well, this sure sums up. great posts there, guys! much appreciated.

I bet this will be very useful for those like me looking this up on google and whatnot.

thanks again!!

I have my PC and HTPC plugged directly into the UPS and a powerstrip for the speakers, monitors, modem, router, switches, and my Xbox 360.
Been hooked up this way for probably 10 years now.

Zepher said:

I have my PC and HTPC plugged directly into the UPS and a powerstrip for the speakers, monitors, modem, router, switches, and my Xbox 360.
Been hooked up this way for probably 10 years now.

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and your battery still alive? or you mean, u have this setup scheme over these years?
I wonder if this has any impact on the battery degradation.
you know, we're talking about plugging a strip into a battery backup outlets, right..?

Batteries last about 3-4 years.
I have had it setup like that for that long with no issues, and yes, the strip is plugged into the battery backup outlets.
If the power goes out, I can keep on gaming online for 20 minutes or so.

A surge protector is not good to use for a UPS because you can damage the UPS if the surge protection trips (which shorts hot/neutral to ground inside the surge protector). A decent UPS will usually handle this with overload protection but overload protection is not perfect and will not always prevent damage. A proper transformer-based UPS will likely handle this situation better than a cheap/small transformerless like those Cyberpower cheapies that people on this board, for some reason, seem to like. If a transformerless unit does fail to invoke overload protection, you will not only possibly damage it but you will also trip the breaker in your distribution box ("circuit breaker box") which could interrupt anything else you have on that circuit.

Otherwise, it doesn't affect the battery - all it does is add some extra resistance meaning your load could see a lower voltage (maybe a volt or something) but if your power strip is heavy duty with 12 or maybe 14 gauge wires, it should be within acceptable limits.

Again, it is only a problem if it's a surge protector and the protection trips. So as previously mentioned, it's best to use a power strip with no surge protection. It is also much better/safer to use such a power strip on the INPUT of the UPS (if you HAVE to use a power strip on the input) if you have a transformerless UPS.

All that said, I have in a pinch used surge protectors on the input of transformer-based and the output of both transformered and transformerless UPS and have not had a problem. I just wouldn't recommend the surge protector as a permanent solution.

Also, if you do use a surge protector, it's better to use a higher quality one with series-mode protection and/or "protect or disconnect" type circuitry like Panamax uses. If the surge protector can use other methods like these to handle a surge rather than solely relying on MOVs to short hot+neutral to ground, it would be easier on the UPS and less likely to cause a problem.

And one more thing to note: If you do use a power strip (with or without surge protection) on the UPS, only use as many outlets as you need. Use all the outlets on the UPS before using any on the power strip. If your UPS had 4 outlets, your power strip had 6, and you need 6, use all 4 on the UPS plus 3 on the power strip. Don't use just the 6 on the power strip. As long as you don't overload the power strip or UPS outlet, this particular recommendation is not so much for safety so much as it is to ensure the highest efficiency and lowest amount of voltage drop to your loads. If you used the 6 outlets on the power strip in this example and only used 1 on the UPS (for the power strip itself), you'd have more voltage drop. And voltage drop across power wires is wasted power.