Power Filter/conditioner, needed or not?

you definitely need surge protection. all else is snake oil

Joules are a very rough indicator of longevity. I wouldn't overly obsess over this but I'd expect something that has say 2,000 joules to last signficantly longer than something that had 200 joules.

1 joule = 1 watt-second

so, say, 2000 joules = 20 watts × 100 seconds, or 5 watts × 400 seconds, or 200 watts × 10 seconds.

Point?

I'm not sure where the OP gets the impression that living in an MDU will result in cleaner power than in a home. I would think the opposite.

That said, APC is a foolproof proposition. You will get good filtration with the surge anyway. They make a few nice pieces that are slender and fit behind the rack, and work great.

I happen to agree about APC. Their products are solid.

To assume you do not need any power filtering is completely wrong. Everybody has dirty power for the most part. I could not imagine how bad my setup would look and sound without proper filtration.

In my experience the person that knows the most about this topic is Alan Maher. Not a big name company with poor products in fancy boxes. Just solid products in plain boxes that just work really well.

Here's his web site if you're interested.

http://alanmaherdesigns.com/default.aspx

This statement is just plain wrong!!

Power supplies on the majority of appliances, electronic devices, etc. have a high degree of 'built-in' filtering due to their switching power supplies. Surge suppression is certainly needed... power conditioning/filtering- that is another subject altogether.

Actually, switching supplies are more susceptible to power transients. Big hoonking transformers with big caps were almost immune.
You need to consider speed of suppression. A 50 cent MOV will take a lot of current, but they are slow. Milliseconds. Spark tubes or fast diodes can be as quick as 5 nanoseconds. If you are protecting a transformer, a simple MOV suppressor is fine. Modern electronics, like a TV I had that got hit, had no isolation at all. I use Panamax, Trip-Lite, and the lower end Monster stuff. Remember, a transient can come from many places, power lines of course, but CATV or phone lines can nail you. Most phones installed in the last 30 years have the outside box that has fast suppressors in them so they are already protected from that path. A TV antenna can nail you easy. Ground block, loop over ground, usual tricks there. I have never been a fan of APC.

After looking at the above reference, I go back to one of my original rants. Products should be designed for the environment for which they are intended. Powerlines are designed to deliver power to light bulbs and motors, not sensitive electronics. A consumer product, if it has a plug, should be suitable to plug into the wall. "Dirty power" is either a crap product design with a bad power supply design, or snake oil sales pitch.
In the computer industry, we know power is crappy, and we put in big filters.,UPS and distro systems. We are systems engineers, we know how to do that. The computer makers tell us, and demand it in the spec. Consumer products are supposed to just plug in. The consumer should not have to be a systems engineer.
I have no doubt the above reference does make a quality filter product. It is that it should not be needed for a quality consumer product.
End of rant.

Ooooohhhh...they're voiced. Too bad it's not spell checked too.

Joules are an irrelevant metric for Transient Voltage Surge Suppressors (TVSS). The Joule rating only predicts the total amount of energy that can be absorbed by the TVSS; it does not tell you how quickly it can absorb it, nor how effectively it maintains a safe Voltage for your equipment.

The things you should care about are:

1) Clamping Voltage. This is the minimum Voltage at which the TVSS begins to conduct (which is what clamps the transient). This tells you how much residual Voltage your equipment will see. Lower is better, but only to a point. If the clamping Voltage is too low, the TVSS may conduct during a steady-state overVoltage condition; this results in premature TVSS failure. [Caveat: This is the clamping Voltage at the TVSS terminals, so it does not guarantee that this is the Voltage your equipment will see.]

2) Peak kA. This is the amount of current that the TVSS can handle during a transient event. This tells you how rapidly the TVSS can absorb the energy in the transient; if you exceed the kA rating during a transient, the TVSS fails, and your equipment gets the rest of the surge. [The Peak kA rating also gives you a rough idea of the lifespan for most common TVSS designs.] Higher is better. [Caveat: The wiring to your TVSS must be short and non-inductive enough to allow the Peak kA to actually get to the TVSS. If it is not, then you are not getting the full protective benefit of the device.]

3) Clamping time. This tells you how rapidly the TVSS device begins to conduct, which tells you how much of the transient rise time will be let through to your equipment. Faster is better. [Caveat: A slower device mounted at the service entrance will often outperform a faster point-of-use device, due to system impedance.]

Some other background info:

TVSSs of the sort used in almost all consumer products are MOV-based, which is perfectly fine for just about any home use - IF SELECTED AND INSTALLED CORRECTLY. MOVs are sacrificial devices; as they absorb transient energy, they degrade over time. This degradation slowly increases the clamping Voltage, and eventually results in catastrophic failure of the MOV device (invisible from the outside of the device). Thus, an older TVSS may not be providing effective protection even though it still appears to be operating correctly.

Grounding is the single most important part of surge protection. If you don't have a solid earth ground, or if the impedance between the TVSS and that ground is too high, the TVSS will not be able to operate effectively.

Most properly designed devices today have internal surge protection sufficient to handle a reasonable level of transient energy (within the CBEMA/ITIC limits). In fact, anything with a CE mark will have to have been tested to meet the Low Voltage Directive (LVD), so it will have passed a basic EFT test. HOWEVER, this does not mean that a TVSS doesn't help. The equipment power supply probably has MOVs in it; since the MOVs have a finite lifespan, using a TVSS to absorb the bulk of the surge energy will incerase the life of your equipment's power supplies.

Transients come from many sources, not just lightning. Switched capacitors, noisy motors, arcing fluorescent tubes, etc., can all cause transients on your power lines.

The absolute best transient (surge) protection will be accomplished through the following:

1) Put the primary TVSS unit at the service entrance or main panelboard, tied directly to the main building ground. The wiring should be as short as possiblem, and it should be connected either directly to a dedicated breaker in the panel or the main feed. Putting the TVSS at the main service entrance will reduce the Voltage let through to the equipment far more effectively than putting the TVSS in the equipment rack, because the impedance of the in-wall wiring works in concert with the TVSS to reduce the let-through. Look at it this way: Assume the TVSS lets through a 1 ms 800V spike. If the TVSS is in the rack, your equipment will see 1 ms at 800V - exactly what the TVSS lets through. OTOH, if the TVSS is at the panel, the impedance in the in-wall wiring will reduce the remaining spike by some amount, so your equipment will see something more like 0.7 ms at 500V. A local rack-mount TVSS can help to reduce the remaining transient levels, but the whole-house system is the main and best source of protection.

2) The main TVSS unit should cover all signal lines from outside the building, including anything that is connected to your equipment. All of these should be tied to the same groundnig point. It does no good to tie your power line to ground if a transient takes the whole ground plane up by 1500V and the cable stays at 0. Your equipment will be just as fried as if the 1500V spike had come in on the cable line. [Caveat: DO NOT install a second ground system into your house - this can be extremely hazardous. High-speed, high-energy current flow operates very differently than the "normal" electrical circuit theory everyone understands - don't risk it unless you have serious experience in grounding and bonding distribution systems.]

3) Series filtering is a good idea, and is a "premium" adder to many TVSS devices. However, it may not make any difference if you didn't have a noise problem to begin with.

Yes, yes to all that Mauney but my comment was to the poster who asked a rather specific question on a limited subset of plug-in devices and it looks like that's all he's about to use. You'll generally get greater longevity with a unit that has a higher joule rating.

This is true, but you often will find cheap TVSSs with very high Joule ratings that do a lousy job of actually clamping transients. I don't want a surge suppressor that outlives my equipment rack - what's the point?

...and exactly which of these brands use anything other than MOVs for transient suppression?

I would also suggest that you look over UL1449, then look at the performance of MOV-based TVSS systems that are properly designed and installed.

As for speed, MOV-based TVSS units respond FAR faster than "milliseconds" - have a look at the C3 combination wave and the clamping time required to meet the specs and get the UL listing.....

Within the brand subset he was considering do you think there's a clear winner? Also, since he live in an apartment complex of some sort, for all one knows (maybe building management does) they may already have installed a facility wide suppression system. I also don't want a surge suppressor that's going to be compromised in a short amount of time due to baby hits. IMO, he'd be adequately served by devices from Panamax, APC, Tripplite, and a few others. Should be a wide variety to choose from that have joule ratings >2000. Myself, for my HT, I've got a device from Transtector that's based on Silicon Avalance Diodes. Not sure if they make it any more.

Well, he said:
..so he's already decided based on brand as opposed to specification. Having been in the PQ industry for a couple of decades, I can tell you that I certainly DON'T see APC as "THE" TVSS company. I don't mean to bash them - their products appear to me to do what they say they do - but there are quite a few other companies that specialize in TVSS and have really great products. [I see APC as a big name in single-phase UPS for small business applications - that's their real claim to fame.] There are also several companies that sell junk backed up by a bunch of marketing pseudo-science. Unless you have some basic understanding of the physics behind what the product does, you cannot make a rational decision about a specific product. Chu, you should be one of the first to see this - you're generally right on top of the underlying principles.


I wouldn't expect this at all - I'd never expect a landlord to spring for the cost of a suppressor. Even if they did, I have no confidence that it would be checked and replaced if/when it reaches end-of-life. Also, I would be more worried about high source impedance, noisy HVAC compressors, etc. in that sort of environment than in a single-family suburban situation.


True, but the kA rating still tells you more than the Joule rating.


SASD TVSS units are indeed fast, but they generally can't handle a very large surge. They are generally rated in the hundreds of amps, while MOV units are rated in the 10s or hundreds of kAmps. Most of what Transtector appears to be selling now is MOVs for the main panelboard, with SASD at the point-of use. This is a reasonable strategy - you get the speed of the SASD at the equipment rack backed up by the high surge current rating of the MOV device at the service entrance. The trouble comes in if you only have the SASD unit and don't have the MOV "heavy hitter" to absorb the really big transient if/when it happens.

Then you'll need an online UPS. Rather expensive and inefficient.

If you really need surge protection, then the whole house type of surge supressor that is installed where power enters your home is the way to go.

If you live in most urban settings, you don't need surge supression.

No argument here!


OK, for a $200 price point:

If you want a surge suppressor, go with a whole-house like the Cutler-Hammer CHSP or equivalent.

If you want a power filter (with nominal surge suppression), go with a Furman unit.

You won't get anything that can really stabilize Voltage and filter and provide serious surge suppression at that price point.

I know and considering he's living in Canada as opposed to say Florida, it's not the most terrible choice.

I don't see them as "THE" company either. But you know Mauny, I just haven't had it in me recently to get into the underlying principles thingie. I'd have to explain it in a very layman's kind of way, prioritize it, tell people that I don't know of one single place that tests them all the same so take what each company says with a grain or a ton of salt. I just didn't and don't have it in me.


Well a place that's got a building mgmt on top of things might go for it but that depends on the environment it's in. It's not entirely common but it's not unusual. Asking doesn't hurt much.


Assuming you can believe both, sure. But again, he asked about joules, I confined my reply to joules. Not saying there aren't other things but...


You'll find SAD's often quoted in specs for telco installs. Not by themselves but strategically placed. And I've got a MOV heavy hitter with the whole house. Besides it's cool to have something different. I just don't think about it anymore Mauney.

If you look at the spec, anything fast has more than an MOV. Look for a "response time". 5 to 10ns is what you want. The $12 strips have a single MOV in them. They can take a lot of energy, but are damaged in the process. Fine, as it means they died, not your equipment. My preference is Panamax. Trip-lite uses filters before the MOV for the same effect. With the filters, the also clean up any garbage on the line. My AV system happens to be on a Monster strip. It had the features I wanted at a fair price, and equipment warranted against power fault. My big power amps just have MOV's inside after the fuses as the Hafler's have big inefficient E-core transformers. They just plain don't pass transients! They are also plugged into a FURMAN sequencer that I believe also has MOV's in it.

It is quite correct that diodes and spark gaps can't take high power hits. That is why you still need the MOV behind it. The diode only has to last long enough for the MOV to start to conduct.

For protecting consumer equipment ( TV, Computer), When I lived in Colorado, we had proximity hits all the time. I lost 2 TV's. Bought several Panamax units. Still have them 20 years later and have never lost anything that was plugged into them.

The problem with the hole house unit is it should be installed by a licensed electrician. That makes it very not-cheap. It is amazing they are not required by code, they should be in every home. Maybe I'll put one in when I put in a RF blocking filter so the power company can't look for "smart" devices in my house and try and turn them off. They have technology, I have technology, he, he, he. (Picture mad scientist snicker)

Not necessarily.

That's actually not true. MOV-only units can be built to be fast enough to clamp almost any normal transient effectively - but it takes some design effort. The inconvenient fact is that the combination of PCB layout and installation wiring has a lot more to do with the clamping time than the technology used. (In fairness, the MOV units I'm referring to are fairly expensive industrial devices, but the point is valid.) I would rather have a well-designed and properly-installed all-MOV TVSS than one with combined technologies and a crappy PCB layout.


All of these brands make TVSS that perform pretty well, though I don't find Monster products to be a good value realtive to price paid. I currently have samples of Furman, Monster, and Tripp-Lite that I use or have used. The Monster unit died prematurely due to a contact failure that had nothing to do with the TVSS function - I can't say that it's inconsistent with my experience with Monster products.


That depends on local codes and the homeowner's level of comfort and experience, but it's a valid point. Truth be told, they're really not that hard to add to a panel, but you are correct that it's not appropriate for a casual DIY'er.


Why? Code is only about safety and preventing failures of the in-wall wiring. the NEC and inspectors couldn't care less about protecting your personal electronics. [That said, I think it's a good idea for any new house to have a service-entrance TVSS. I just don't know how to get it added to the NEC; if you can figure this out, let me know and we can make some serious $$$...]


ROTFL....