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UPS surge protection status

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jmblack6307_apc
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UPS surge protection status

This was originally posted on APC forums on 11/22/2010


How can one tell the status of ups surge protection since they do not have surge status led's like regular surge protector strips do?


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rau_apc
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Re: UPS surge protection status

This was originally posted on APC forums on 11/23/2010


Surge protection is given by MOVs and in either way, be it a surge strip or an UPS, the surge protection circuit can only tell you it is bad when it has completely failed which means a short circuited MOV, in surge strips this warning is given by an LED that turns off or turns on, depending on the make of of surge protector, and this LED is controlled by a thermal fuse that open the circuit due to an overheating condition of the MOVs. In the case of UPSes, if an MOV clamp short, many things can happen, the circuit breaker can turn off or any of the things said on the last message can happen. One thing is certain, you will know when and MOV short circuits for good, it you're gonna feel a bad burning smell.

Message was edited by: rau

See Answer In Context

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jmblack6307_apc
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UPS surge protection status

This was originally posted on APC forums on 11/22/2010


How can one tell the status of ups surge protection since they do not have surge status led's like regular surge protector strips do?

BillP
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Re: UPS surge protection status

This reply was originally posted by Angela on APC forums on 11/22/2010


good question. i am not so sure there is a way since a surge protector's primary function is to provide surge protection. a UPS essentially has surge protection as an added ability of being a UPS. i am not so sure any of our UPSs can tell you when the surge protection has failed but they do have lifetime equipment protection policies on most consumer level models if the protection does fail and a piece of attached load fails due to the APC UPS failing. there is also a warranty of course if a surge protection failure occurs where the unit "fails open" and sacrifices itself to protect your equipment. this should give you some peace of mind 🙂

[more information on equipment protection policy|http://www.apc.com/support/service/equipment_protection_policy.cfm]

rau_apc
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Re: UPS surge protection status

This was originally posted on APC forums on 11/23/2010


There's one big difference between surge strips and UPSes. The MOVs or Varistors put inside surge strips has the role of protecting against surges and suisteined overvoltages. The basic difference between these two power events is that the first one is high energy and happens very fast, comes and goes very quickly, the second one is low in energy, but comes and stays for a longer time. But what doest it have to do with anything? Wait, I'll explain.

Surge strips is prone to overheating since it has to protect the load using MOVs only (not necessarly, but that's the cheapst approach and mostly used). The MOVs used to protect against overvoltage in surge strips are usually 130V for a 120V wall outlet and 230V for a 220V wall outlet. The drawback of this approach is that while this "low" voltage MOVs can give protection against surges and sustained overvoltages, when there is a sustained overvoltage condition the MOVs heats up very fast, it conducts a lot of current and thermal fuses open the circuit so as to protect the load and the surge strip agains dangerous fire, the LED will tell you the surge strip is gone and you have to buy a new one. Now the UPS works differently, I'm talking about the APC UPSes that I have the chance to analize their internal components. So, the APC upses use MOVs right at the power input inside the UPS and these first MOVs are of a higher voltage, sometimes 230, 250, 300, 380, 530V MOVs. These high voltage MOVs will never conduct energy when there is a sustained overvoltage condition, what the UPS do is open the circuit via relay, not letting the sustained overvoltage reach your equipment and the sensitive components inside the UPS now right after the UPS transformer and relays, there's another MOV, usually 150V that is used to protect your PC against the smaller surges let through by the first MOVs. This 150V MOV will never see sustained overvoltages so it is unlikely the first MOVs and the one placed after the relays will ever burn down because of overvoltage like usually happens with surge strips, so no need to warn the user by the means of an LED or something like that. The higher voltage MOVs placed at the input will absorve most part of the surge and the last MOV will absorve the residual surge. One good thing of this approach is that you won't have a burnt UPS because of a sustained overvoltage condition, UPSes coast hundreds of dollars, surge strips can cost 15 to 50 dollars.

Message was edited by: rau

jmblack6307_apc
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Re: UPS surge protection status

This was originally posted on APC forums on 11/23/2010


I emailed customer service. Sounds like if surge protection fails, unit as a whole wont operate. Here is there response:

You are correct, if the UPS has encountered a surge event, it will no longer pass power through the outlets. All surge events are different, so it's difficult to say whether lights or alarms would indicate a surge. In some cases, the UPS simply will not power on and will have no power from the outlets and no lights. At other times the UPS might still be "on" with visible LEDs, but the outlets themselves will not pass power and another scenario might have the UPS in a solid tone alarm state that will not be silenced until the battery is disconnected. These are just some examples of behavior you might see if a UPS encounters a surge and sacrifices itself to protect your equipment. Unfortunately, there's no way to definitively tell how a particular UPS will react because the surge
events can vary so dramatically.

rau_apc
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Re: UPS surge protection status

This was originally posted on APC forums on 11/23/2010


Surge protection is given by MOVs and in either way, be it a surge strip or an UPS, the surge protection circuit can only tell you it is bad when it has completely failed which means a short circuited MOV, in surge strips this warning is given by an LED that turns off or turns on, depending on the make of of surge protector, and this LED is controlled by a thermal fuse that open the circuit due to an overheating condition of the MOVs. In the case of UPSes, if an MOV clamp short, many things can happen, the circuit breaker can turn off or any of the things said on the last message can happen. One thing is certain, you will know when and MOV short circuits for good, it you're gonna feel a bad burning smell.

Message was edited by: rau