Chain Surge Protectors / UPS in series

[vanished]

Every piece of equipment that claims some level of surge protection is rated in how many Joules of energy it can absorb.  If you have several surge protectors, could you not chain them for moar protection?  I've done some reading on this and the consensus of people who seem to know what they're talking about is that in fact you should not.  Somehow the protection components will interfere with each other and could possibly even reduce your level or protection.  I'm not entirely sure how that's possible, but I'm going to follow that advice unless I hear convincingly otherwise, seeing as how it's easier to trust one unit to do what it claims than it is to combine many and take a chance that all these people were wrong.

 

So, is this true?  Should you not do it?  Does it change anything if you're attaching a UPS to a surge protector or a surge protector to a UPS, as opposed to using just two "normal" surge protectors?

[Ganz]

I personally wouldn't do it.  Just doesn't feel right to chain surge protectors together I don't know.  I would much rather have one that does the job really well than two that kind of due the job.  See scrapyard wars with Austin.  Totally different concept but the analogy applies.  There is a reason we don't see multiple PSUs per system!

[Mira Yurizaki]

There's nothing wrong with daisy chaining surge protectors and stuff as long as the total load on that circuit or protector isn't exceed by whatever safety margin there is.

 

If you are going to daisy chain them though, put the better one at the mains socket itself.

[W-L]

3 minutes ago, Ryan_Vickers said:

Every piece of equipment that claims some level of surge protection is rated in how many Joules of energy it can absorb.  If you have several surge protectors, could you not chain them for moar protection?  I've done some reading on this and the consensus of people who seem to know what they're talking about is that in fact you should not.  Somehow the protection components will interfere with each other and could possibly even reduce your level or protection.  I'm not entirely sure how that's possible, but I'm going to follow that advice unless I hear convincingly otherwise, seeing as how it's easier to trust one unit to do what it claims than it is to combine many and take a chance that all these people were wrong.

 

So, is this true?  Should you not do it?  Does it change anything if you're attaching a UPS to a surge protector or a surge protector to a UPS, as opposed to using just two "normal" surge protectors?

 For a UPS they have low level surge protection cause most are line active so they will directly cut itself off from the mains and use the battery backup if there is a spike or things get too noisy so it wouldn't require a surge protector before or after it, usually having it before can cause false triggers from what I've heard. 

 

As for chaining together surge protectors it's usually because people overload their circuits but not unheard of for one surge protector to trip another. 

[AresKrieger]

The chain will be as weak as the weakest link (generally the ground protector connected to the wall), so which every surge protector give you the least protection is likely the most you'll get out of it, or you'll simply only be protected by the one in the wall which is connected to ground, now if you connect the ups to a single surge protector it should protect the ups some since the surge would go through the protector first.

[alpenwasser]

This will probably not be the same for every surge protector. For example, if a certain surge protector works based on one or several capacitors, your overall capacitance in the chain might indeed sink below what a single one can provide (depending on how specifically the circuits are designed), according to the law for connecting capacitors in series:

 

1/C_total = 1/C_1 + 1/C_2 + 1/C_3 + ...

 

Good surge protectors should be more complex than a simple capacitor, of course, which makes the overall outcome less predictable. So yes, I'm inclined to agree with whatever people advised you against this.

 

If you want to know with a higher degree of confidence, take a specific surge protector apart and analyse the circuitry (or have somebody do it for you).

 

EDIT:

I'm bringing up capacitance because a capacitor's capacitance influences how much energy it can store (0.5 * C * V^2).

 

EDIT 2:

Also, here's a DIY homemade surge protector, as an example of one implementation:

http://www.brighthubengineering.com/diy-electronics-devices/90219-build-a-simple-whole-house-surge-protector/#imgn_0

 

One could try to simulate this circuit, then connect two in series and see what happens.

 

EDIT 2:

Here's another one:

http://www.eleccircuit.com/diy-surge-protector-circuits/

 

[vanished]

36 minutes ago, alpenwasser said:

 

EDIT 2:

Here's another one:

http://www.eleccircuit.com/diy-surge-protector-circuits/

 

 did you actually read that one!? Look at this shit:

Quote

When has a thunderstorm. Electrical is off, or power surges the extreme, but sometimes we need to use the electrical appliances. And in sensitive electrical appliance damaged easily. Power surges a little. Might make it wastes. In particular surge. At you firstly turn on the switch. Should have the power to delay, gradually release it into these appliance. I would like to introduce the concept of a two ac delay circuits. Which both two circuit is designed in easily ideals for all people.

lmao  

[alpenwasser]

5 minutes ago, Ryan_Vickers said:

 did you actually read that one!? Look at this shit:

lmao  

Yes, I did read it. Bad English does not equate bad circuit design.

 

And it is just an example.

 

Although I would simulate and test any circuit you pick off the internet before hooking it up to something important. If not for safety, then at least to properly understand it.

[AresKrieger]

55 minutes ago, alpenwasser said:

 

1/C_total = 1/C_1 + 1/C_2 + 1/C_3 + ...

 

 

The grounds should all be the same, so in essence they (the grounded capacitors) are in parallel, not series, however additional protectors would be worthless due to components failing after reaching a given power threshold in the first guard, thus ceasing to impede current after a certain power level resulting in hardly any energy dissipation before hitting the next one (unless the surge guard acts as a breaker in overload situations), also each additional surge protector down the line would provide less dissipation when the original surge guard doesn't fail due to the ground being charged by capacitors further up the chain (ground can only discharge so quickly)

 

So in essence more surge guards shouldn't make things any worse dissipation wise (minus some impedance and more draw from the wall) but they are rather pointless, you could use 1 additional (further up the chain) if your ups is not good at surge guard.

 

 

 

[alpenwasser]

@AresKrieger Oh, good point about the common GND.

 

[vanished]

@alpenwasser @W-L @AresKrieger @M.Yurizaki @Ganz

 

So if you had to choose between a UPS (line interactive, pure sine wave, AVR) with ~1000 joules of surge protection or a regular old surge protector with ~1750 joules, which would you say is better on just protection alone (I know the UPS obviously offers other benefits)

[AresKrieger]

If a product has 1,000 joules of protection, that means it can take ten 100 joule hits, or one 1,000 joule hit. So take that as you may, also does the UPS still have functionality once surge protection is no longer functioning? If so I vote UPS due to the additional functionality (I'm leaning that way anyway though)

 

[W-L]

5 minutes ago, Ryan_Vickers said:

-SNIP-

The UPS, the AVR is really good if your power fluctuates a lot and isn't stable as it can correct for that, in terms of protection the UPS does do surge protection just a little differently as it will just switch of mains and into battery backup if things get really bad with as mentioned lower level surge built into most units. 

[vanished]

2 minutes ago, AresKrieger said:

If a product has 1,000 joules of protection, that means it can take ten 100 joule hits, or one 1,000 joule hit. So take that as you may, also does the UPS still have functionality once surge protection is no longer functioning? If so I vote UPS due to the additional functionality (I'm leaning that way anyway though)

 

Actually that brings up another question I hadn't even considered.  Does 1000 joules mean it can take spikes up to 1000 joules, but any amount (assuming they are sufficiently spaced out) or is it like the surge protection gets "used up" so after absorbing that it's no longer providing any protection?

 

As for the bolded part, I would think so unless they designed it to stop functioning

[vanished]

2 minutes ago, W-L said:

The UPS, the AVR is really good if your power fluctuates a lot and isn't stable as it can correct for that, in terms of protection the UPS does do surge protection just a little differently as it will just switch of mains and into battery backup if things get really bad with as mentioned lower level surge built into most units. 

So the surge protector will try to absorb the shock or redirect it to ground or something, and the UPS will just disconnect itself from mains to stop the propagation?

[AresKrieger]

4 minutes ago, Ryan_Vickers said:

Actually that brings up another question I hadn't even considered.  Does 1000 joules mean it can take spikes up to 1000 joules, but any amount (assuming they are sufficiently spaced out) or is it like the surge protection gets "used up" so after absorbing that it's no longer providing any protection?

 

As for the bolded part, I would think so unless they designed it to stop functioning

It can take a 1000 joule spike once, but is only rated for 1000 over it's lifetime (unless otherwise stated on the device), it will have an indicator to say whether the surge guard is still functioning (or should but I doubt it is a cheap one)

[W-L]

3 minutes ago, Ryan_Vickers said:

So the surge protector will try to absorb the shock or redirect it to ground or something, and the UPS will just disconnect itself from mains to stop the propagation?

Yes in general that will be the case sometimes if it's small and the voltages varies the AVR can correct for it automatically, the surge protector just suppresses it and will slowly wears out so as mentioned it needs to be replaced after a while if you have poor mains power. 

[vanished]

1 minute ago, W-L said:

Yes in general that will be the case sometimes if it's small and the voltages varies the AVR can correct for it automatically, the surge protector just suppresses it and will slowly wears out so as mentioned it needs to be replaced after a while if you have poor mains power. 

so in theory the UPS will last longer because the way it does surge protection doesn't get worn out?

[W-L]

2 minutes ago, Ryan_Vickers said:

so in theory the UPS will last longer because the way it does surge protection doesn't get worn out?

Yes, the most times you see voltage surges or changes the AVR is what will be doing most of the work:

[Scheer]

Just throwing this out there in case you are actually looking to buy a surge protector that is actually going to do something... its going to be $100+, and cannot say Monster on it. If it doesn't click when you plug it in, its an el-cheapo with about $0.10 of electronics inside of a plastic housing (with a few exceptions of course).

 

Innovolt makes some good ones, we have thousands of PP15/PP20s, and I only know of one that has ever failed. It was from a direct lightning strike on a building that melted most of the wire in the building.

 

As for UPS, I've had three of them fail on my in my home alone, and about a year ago at work we had one of the ~$15k APC units go out and take a few servers with it. That being said, I still run UPS units at home because its convenient, although not the best protection.

[vanished]

28 minutes ago, Scheer said:

Just throwing this out there in case you are actually looking to buy a surge protector that is actually going to do something... its going to be $100+, and cannot say Monster on it. If it doesn't click when you plug it in, its an el-cheapo with about $0.10 of electronics inside of a plastic housing (with a few exceptions of course).

 

Innovolt makes some good ones, we have thousands of PP15/PP20s, and I only know of one that has ever failed. It was from a direct lightning strike on a building that melted most of the wire in the building.

 

As for UPS, I've had three of them fail on my in my home alone, and about a year ago at work we had one of the ~$15k APC units go out and take a few servers with it. That being said, I still run UPS units at home because its convenient, although not the best protection.

I guess this is one of those things where you could spend an almost infinite amount of money approaching 100% protection, and it just comes down to how far do you want to go down that road before it's enough.

[Huntsman]

It all depends on the topology. And generally, you wouldn't get more "protection" by daisy chaining them. Why? Because a good UPS is designed to sacrifice itself and take the whole surge load and contain it, even if it exceeded the ratings. The ratings are a guarantee of how much energy it can take without failing but any more than that it is supposed to just sacrifice itself.

 

Also, although the lines are blurred with recent products, specific devices are actually meant to do specific things:

 

AVR (Automatic Voltage Regulator): They regulate voltage so that the perceived voltage remain constant regardless of voltage surges or brownouts. They don't do well with large surges since they are meant to regulate within a small window of fluctuation.

 

UPS (Uninterruptible power supply): These are supposed to ensure that the devices connected will not immediately lose power on a brownout or power outage.

 

Surge/Spike Protector: They take the brunt of everything. Absorbs sudden bursts of energy and dissipate them as heat or destroys a part of itself. The protection component (usually a MOV or TVS but spark gaps work differently) can usually be reused depending on the energy it took. It works by presenting the extra energy a short in hopes that the energy would not propagate further down the line. If it's within ratings, the insulating layers will have a hole burnt into it and "heals" itself after the event. Else, the entire thing will do a kamikaze and take as much energy as possible down with it. After one big blow, a good protector will cut off power to the output to render itself useless since it will no longer be able to provide protection.

[leadeater]

@Scheer and @Huntsman have done a great job here, I would like to add a few points though. Apologies for reviving an old (ish) thread.

 

General surges can be dealt with rather well by a good surge protector or UPS but when it comes to something like lightning anything in the price range for home isn't going to cut it that much. If you get a direct strike there is so much energy that lightning will typically go right through a surge protector and take out everything behind it, the voltage is so high arching will happen and ionize the air which itself is conductive so it will find a way through directly or indirectly.

 

As for UPS's the type and quality matters a lot. Eaton has a very easy and good guide on this, 3-5-9. The only type I buy are Online Double Conversion, meaning I only buy 9 series or higher models from Eaton. Too many times when it's come to the crunch and a Line Interactive UPS is called on to protect the devices behind it they have failed to do so, also I've had way too many fail just from powered on hours but those were all APC and I never use them anymore. Not that APC don't make good ones but they have too many cheap rubbish that people insist to waste their money on.

 

See image for why Online Double Conversion is so much better.

http://www.eatonguard.com/images/9315/9315-graph01.jpg

 

In large installs like in server rooms there is usually a high quality surge protector in front of the UPS, generators also run through these, so yes it is safe and in my experience common to have have surge protectors in front of UPS's so long as both devices are of good quality. At work we have two 160KVa UPS's well apart from each other in a restricted access area that not even the general IT system engineers are allowed to go in to, not that you would want to if you understand just how big 160KVa x2 is .

 

The local hospital here is another step up from us, their IT is smaller but they have other requirements. They have three different power distributions within the buildings: General, Medical and Comms/IT. There are strict rules for what devices can be plugged in to each type. The medical and Comms/IT power is filtered through what I'll simplify as 'Medical Grade Filtering' which you can just think of as a power substation with damn expensive equipment in it. There are 3 main power feeds in to this, two from different national grid sources and the third is from onsite huge gas generators. Comms/IT also have Eaton UPS's locally in each cabinet but they are looking at centralising these in to a single large redundant setup per building, most medical devices have their own internal batteries.

[vanished]

3 hours ago, leadeater said:

In large installs like in server rooms there is usually a high quality surge protector in front of the UPS, generators also run through these, so yes it is safe and in my experience common to have have surge protectors in front of UPS's so long as both devices are of good quality. At work we have two 160KVa UPS's well apart from each other in a restricted access area that not even the general IT system engineers are allowed to go in to, not that you would want to if you understand just how big 160KVa x2 is .

All good to know, thanks

 

And yeah I can imagine - I remember from work the electrical guys getting on their bomb suits just to flip a switch on the 25 kV site supply  

[Huntsman]

On 9/4/2016 at 0:13 AM, leadeater said:

The local hospital here is another step up from us, their IT is smaller but they have other requirements. They have three different power distributions within the buildings: General, Medical and Comms/IT. There are strict rules for what devices can be plugged in to each type. The medical and Comms/IT power is filtered through what I'll simplify as 'Medical Grade Filtering' which you can just think of as a power substation with damn expensive equipment in it. There are 3 main power feeds in to this, two from different national grid sources and the third is from onsite huge gas generators. Comms/IT also have Eaton UPS's locally in each cabinet but they are looking at centralising these in to a single large redundant setup per building, most medical devices have their own internal batteries.

The "Medical Grade Filtering" isn't about damaging the expensive equipment, but about not injuring (this is an understatement) the patient when shit happens