powerstrip blinking

[PROCOBOB]

Hi, At the risk of asking a stupid question, the red light on one of my power strips is blinking erratically. Is this something to be concerned about? Bob

[Bert Byfield]

No. It's just the neon bulb showing its age.

[Joseph Meehan]

It is likely flickering and that is because the light is old. If that power strip is being used as a surge protector, it is likely too old to be working any more. They don't last forever.

[PopRivet]

light on one of my

something to be

light is old.

protector, it is likely

forever.

Irish Math needs updating. The blinking neon bulb had ZERO to do with surge protection! Surge protectors, usually varistors, are solid components and NOT subject to aging the same as a bulb or an electrolytic capacitor. That stip's surge protection, which is minimal in most power strips anyway, is 99.9999% likely to be just fine! Please don't use irish math that costs people money when it's not warranted.

Pop

[Tom Baker]

agreed. When I asked, the technician laughed at me. TB

[PrecisionMachinisT]

Bingo....

Give that man a cigar!!!

========

The varistor in them surge strips is a protection device, usually a one-shot deal, and is wired in parallel with the protected load--in theory, if line voltage ever goes over at certain definate set point, they short out.....thus tripping the circuit breaker or blowing the fuse to the branch circuit feeding the unit.

Having relatively high dollar computerized equipment in our machine shop, we always add a set of them just downstream from the mains fuse block whenever the machine wasnt already equipped with a set as supplied from the factory.

[Dan Hartung]

As others noted, it's just the bulb. The power strip is likely aging, though, and if it makes you feel better you can move it to a place where it's serving lesser-value equipment. Think of it a little like the "penny test" for tires.

You didn't note if it has built-in surge protection; usually a "power strip" so named does not. It may not be offering you any equipment protection to begin with.

A computer, for instance, should be on a high-quality surge arrestor such as those made by ADP or Tripp-Lite, ideally isolating different parts of the system from each other. Every time you turn on your printer, for example, you could be adding a surge to the line that is damaging your computer. Personally, I think the added peace of mind from buying a $50+ surge device is worth it, considering the value of my computer equipment. But not everything needs that kind of protection.

[Greg]

A lot of these strips use a neon light and cheap neons do flicker.

[Joseph Meehan]

True. ... Sort of.

After years of service and many small, surges those inexpensive surge protectors tend to loose their abiltiy to protect.

[Pop Rivet]

inexpensive surge

Since you want to be specific: No, very specifically and emphatically, the blinking neon bulb has ZERO to do with the condition of the surge protection, which was my original point. Additionally, varistors et al have a "knee" or breakdown area where they begin to conduct. That "knee" does vary within percentages with age, but it does NOT negate the protection afforded; the full breakdown point is stable to wihin 5% as a rule, of the specified voltage, over the life of the component, The unfortunate and uniknown state of the varistors in the surge protection however, plus how the protection is installed, is, in the cheaper strips, completely and totally unknown unless there are monitor LEDs to indicate their condition. Once stressed, a varistor DOES lose its ability to dissipate the amount of joules it was rated for at manuifacture. When overtstressed, the varistor opens up completely, and there is no protection form the OPEN varistor. Usually there are 3 varistors: One from hot to earth, one from neutral to earth, and one from hot to neutral. IF one if hit hard enough to cause it to go short , after which the normal 120V ac current burns it out and it opens up, you still have the other two in place, BUT for practical purposes, protection is compromised, although not lost, because of the triad of components. Even with one gone there is still SOME protection left, in all three directions. It's non-intuitive, but is the case.

For those who might be interested, surge protection is measured in joules; the higher the number of joules it can handle, the better the protection. Current and/or voltage are NOT an indication of how MUCH surge protection is being provided. So look for the joule ratings; it's sort of like watts, but more indicative of the strength of the protection at any current or voltage combination.

Pop

[Pop Rivet]

on one of my power

concerned about?

likely aging,

a place where

like the

usually a "power

equipment

surge arrestor

different

on your

line that is

peace of mind from

value of my

protection.

>

[Tom Baker]

I didn't read Mr. Meehan's post to l1. Power strips become less reliable surge protectors with age.

1. Power strips aren't very good at surge protection in any case, not withstanding money back guarantees. TB

[Joseph Meehan]

Which is true, as I tried to indicate. However there is a type of relationship. A flickering neon light is a good indication that it is old. All authorities I have read, with the exception of you have indicated that age and use of surge protectors does tend to point to a greater likelihood of reduced protection.

I offer no personal or verifiable objection to your arguments that appear to suggest that age is not a factor in the reliability of surge protectors. I only note that others have appeared to offer different opinions.

[clifto]

Sort of, but not exactly. They also "clip off" short transient overvoltage pulses. Each time they do, they take a little "hit" and degrade a bit.

[Pop Rivet]

had

those

neon

surge protector.

age.

any case,

Item 2: Correct. Literally, a "power strip" only has a switch and some outlets. It says nothing about any kind of surge protection. A few lo-joule varistors is NOT very good surge protection for anything but everyday inductive load switching, etc as in motors, xfmrs, and so on. They do little to nothing for outside surges coming into a house mains or telephone line. Most, not all, damaging surges to computer equipment comes in on the phone line anyway, not via the mains where there is a stepdown xfmr to help limit them, and more inherent stability.

Item 1: Isn't really a very mean ingful statement. Coming from the MTBF and failure compliance world, "age" is relative, and without a reference, meaningless. How much aging? How long does it take for surge protectors to become less reliable? Etc. I think, if htat guy knows what he's talking about, he's actually saying not to trust them because the surge protection can be "used up" if you will, and no longer present, after a surge, and the user never gets any kind of indication that such an event has occurred. So, if it happensw again, Blammo! And the surge protector didn't work! Not the second time, anyway. Shelf life of varistors, tridacs, etc., is in the order of decades, and useful, non-surged life is nearly equivalent. The -problem- is not being able to tell WHETHER any damage/loss of protection has occurred. They're not very useful, but at the same time, very important to have. The life of a computer is so short that a new surge switch with any new computer is more than en ough to keep things current. Obviously, as you said, if it really matters, spend the $50 or so to get a good one or better yet an UPS.

Thanks, I'm disabled and like to talk "shop".

Regards,

Pop

[PrecisionMachinisT]

Thats why I said "in theory"..........

[w_tom]

Pop Rivet accurately describes how MOV protectors must fail. MOVs degrade as intended and as speced by charts in manufacturer data sheets. That is 'degrade' which is completely different from a catastrophic failure also known as 'vaporize'. A vaporized MOV has operated well beyond what the manufacturer requires and does not even appear on those data sheet charts. A vaporized MOV is so ineffective as to be called grossly undersized and completely ineffective.

There is good reason to grossly undersized a protector. A properly sized protector with more joules will earth a surge. Human should never know the surge even existed. But with grossly undersized (and overpriced) protectors, then the naive will *assume* a protector failed to protect an adjacent appliance. In reality, protection that already exists inside appliances was not overwhelmed by the same tiny surge that catastrophically (unacceptably) destroyed a grossly undersized protector. With or without the adjacent protector, that appliance internal protection would never have been overwhelmed by that tiny surge. But now a misinformed human is recommending a grossly undersized and overpriced protector. How to increase profits (get the naive to recommend a product) without installing sufficient MOVs.

Any protector damaged by one surge was grossly undersized and should have never been purchased - too few joules. And yet that is what so many naive will recommend only because it vaporized - was grossly undersized. The only acceptable failure mode for MOVs is degradation. Vaporization means the human bought a defective protector. Not just undersized. Grossly undersized. Too few joules. Grossly overpriced and defective.

There is no difference between a *high quality* protector from ADP, Tripplite, or Monster and the $5 protector if all have same joules rating. All are simply a $3 (retail) power strip with some $0.10 parts installed. Some are then grossly overpriced at $50. Only other part that makes a quality difference is the power strip's circuit breaker. A 15 amp breaker that has nothing to due with surges and must be provided on every power strip for human safety reasons. Some grossly overpriced protectors do not even have the essential

15 amp breaker.

Surge damage is being promoted as if surges were daily events slowly degrading the electronics. Nonsense. Look at the numbers on that protector. Threshold or let-through voltage of 330 volts. Protector rarely sees or responds to anything. For a typical eight years, protector can remain inert - do nothing. A surge is a rare event that occurs maybe once every 8 years (varies based upon weather, underlying geology, etc). Furthermore, all appliances have internal protection that make daily noise transients on utility wires irrelevant. The surge protector never even sees that noise. Protector is sized so at to remain fully functional after that rare event. Joules is the rating. How many joules on the recommended ADP or Tripplite protector? Joules is the ball park number for a protector's life expectancy.

Ne> PROCOBOB wrote:

[rck]

As mentioned, the cheap power strip surge protectors don't protect much. When lightning hit the pole in front of my house. I saw a spark jump from one prong to the other on an outlet. It also came in on the phone line. The surge protector power strip was left in smoking ruins. However, I had a battery backup power supply for the computer and the computer survived because on the battery backups, the ac charges the battery and in turn a DC to ac switching supply creates the ac for the load, thus isolating the load from the incoming power. At the time I had an external modem and the incoming high voltage smoked the modem. Because it was an external modem, it provided enough isoation to protect the computer. Aside from having to replace the modem, two phones, a power strip, and all the lightbulbs that were on at the time, there was no other damage. I had turned all appliances off and unplugged the stereo from the power strip when the storm approached. I think that's the best protection in an electrical storm. I don't think the surge protector in the power strip would have offered any protection.

Bob

[PopRivet]

"rck" wrote in message news:K7aLc.9265$ [e-mail]

don't protect

house. I saw a

It also came in

was left in

supply for the

battery backups,

switching supply

from the

and the incoming

external modem, it

Aside from having

all the

other damage. I

stereo from the

that's the best

surge protector

protection.

Definitely wouldn't jhave made any difference. Since we're telling stories, a few years back we had a close by lightning hit; hair on the arms stood up, strong ozone smell, and also a LOT of smoke coming from the entertainment center, we quickl realized. Which was strange, because we'd unplugged everything and the plugs were laying right there on the floor in plain sight. Only ... we -didn't- disconnect the dc wiring going out to the satellite dish and it came in on that! The strike actually it a tree, and from the burn marks and blasted bark all over the place (tree wasn't damaged structurally but was butt-naked!), it travelled along a nearby farmer's barbed wire fence and jumped to our dish, from the look of it. Between the buried wires and the dish itself, a ten footer, we had a great entrance for those jewels, I mean, joules to flash along. Thank heavens for insurance! Another time it hit the phone in the kitchen at a neighbor's while we were there and a plasma ball jumped from the phone, ran down the wall and across the floor, finally dissipating into the wall on the opposite side of the room! The phone was toast, but no other damage. We never did finish supper; my sister didn't even do the dishes that evening. Then there was the time it hit a power transformer on a pole which my brother in law had just minutes ago parked his brand new Pontiac under. . Glass, metal, fibre, shards of wood & oil all over his previously beautiful car!

This was supposed to be a bad year for lightning in this area this year again, but so far hardly a flash in the sky. Knock on formica! We're far northeast NY state, on the St. Lawrence River. Storms here are low to the grouind, coming up oujt of the valley and sometimes spectacular. There's lots of places worse than here though.

Cheers,

Pop

[w_tom]

Long ago proven even by early ham radio operators. They would disconnect antenna and place antenna lead inside a mason jar. Still suffered damage. Then they earthed the antenna lead. All damage stopped. A lesson that even Ben Franklin demonstrated in 1752.

Earthing is what effective protectors do. Connect an incoming wire (the direct strike) to protection. Protection is not a protector. Protector and protection are two separate components in a surge protection 'system'. Protector (and that plug-in UPS) does not stop, block, or absorb surges

- except in myths. Will a protector or plug-in UPS stop or block what miles of air could not? Of course not.

Shunt mode protectors are not effective dams or surge absorbers. They are only temporary shunts - connection, short circuit, diverter - that connects an incoming surge less than

10 feet to earth ground - the protection. Why do we need such protectors? So that internal protection inside properly designed appliances is not overwhelmed. A surge must be connected to protection before it can enter the building. An effective MOV protector connects that surge less than 10 feet to protection.

Anything that can work adjacent to that appliance is typically already inside that appliance. This explains why both cheap (actually grossly overpriced) power strip protectors and plug-in UPSes don't provide effective protection. Without the less than 10 foot connection to earth, then where is that destructive surge to be shunted to?

In the meantime, computer power supplies must have some of the most resilient internal protection, as even demanded by Intel specifications. Protection that assumes a destructive transient will be earthed before transient can enter the building.

Review detailed numerical specs for a plug-in UPS. It provides same protection circuits found in power strip protectors. Notice the joules. Joules mean both (power strip and UPS) utilize the same protection circuit. Many big name, plug-in UPSes are even grossly undersized - too few joules - ineffective protection. But then a plug-in UPS manufacturer does not even claim to protect from a destructive type of surge. Read his detailed numerical specs - if manufacturer even provides detailed specs.

To protect an adjacent appliance, the protector must stop, block, or absorb the transient. But those are shunt mode protectors. They don't even claim such 'blocking' abilities. Shunt mode protectors are effective when connected 'less than

10 feet' to the same earth ground that all other incoming utilities connect to. This is how ham radio operators even in the early 1900s discovered effective protection. Earthing - and not a plug-in protector - is the protection.

Cheap power strip surge protectors don't protect much; nor do they claim to. Plug-in protectors cannot claim to provide that protection because the short, direct, and independent earth ground connection does not exist. Plug-in UPSes typically use a same protector circuit. They also do not stop or block destructive transients. Earthing is the technique well proven effective for over 50 years, is found in high reliability centers that must operate during every thunderstorm (telephone Central Office and 911 emergency response centers), was even demonstrated by Ben Franklin in

1752, and proven effective by early 1900 ham radio operators.

Protection is about earthing. MOVs are the devices that earth each incoming utility. Protection that also keeps an appliance's internal protector circuits from being overwhelmed. Protection that does not stop or block destructive surges - which is what a protector must do if adjacent to the appliance.

A shunt mode protector (power strip or plug-in UPS) cannot protect an adjacent appliance if it is too far from earth ground and too close to the appliance.

rck wrote: