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Author Topic: is this how you can tell if a powerstrip is bad  (Read 10730 times)

techidave

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is this how you can tell if a powerstrip is bad
« on: June 15, 2009, 10:04:40 AM »
Just wanting to double check what I read on the internet over the weekend.  It said if you are using a working powerstrip that the power light doesn't work anymore, then its bad.  it could be a possible fire hazard.

Anyone have any experience or thoughts dealing with this subject?

I could not find the site I read that on today.   :(


4wd

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Re: is this how you can tell if a powerstrip is bad
« Reply #1 on: June 15, 2009, 03:14:21 PM »
Just wanting to double check what I read on the internet over the weekend.  It said if you are using a working powerstrip that the power light doesn't work anymore, then its bad.  it could be a possible fire hazard.

Anyone have any experience or thoughts dealing with this subject?

I could not find the site I read that on today.   :(

If you're talking about a bog-standard power-strip with nothing more than a circuit breaker for output current overload protection then the options are:
a) the circuit breaker has tripped, or
b) the light, (or the circuit for it), is open-circuit.

If you're talking about a power-strip that has surge protection and the light is lit during normal, (see Note below), operation, then either:
c) same as (a) and (b) above, or
d) the surge protection circuit has failed.

The last option that affects all power-strips:
e) the mains lead is faulty.

In the case of:
(a) reset the circuit breaker - if it won't, replace the board.
(b) if it still supplies power and the breaker trips when you overload it then apart from the light not working there's no need to replace it unless having a non-working light is going to irritate you.
(c) same as (a) and (b).
(d) the only way to tell is pull it apart and look - the safe bet is to replace it.
(e) the only way to check and test is to pull it apart - replace the board.

Note: In the case of surge protected power-strips they can be wired to either indicate normal operation or failure.

I have two power-strips with lights that don't work, I still use them but only because I've pulled them apart and verified it's the light, (or circuit), that's not working.

What it comes down to is: Is it worth your peace of mind to replace them?
« Last Edit: June 15, 2009, 03:21:47 PM by 4wd »

40hz

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Re: is this how you can tell if a powerstrip is bad
« Reply #2 on: June 15, 2009, 03:38:51 PM »
Although it's not a hard and fast rule, I'd be suspicious of using any power strip with a burned out indicator light.

Your surge strip has two main components - a power distribution bus, and a surge suppression circuit. It is not uncommon to lose surge protection, but still have the strip continue to provide power to the sockets. So just because your strip continues to distribute power doesn't mean it's ok to use.

The surge protection component in your power strip uses one of two protection mechanisms - either a varistor or a 'gas discharge' arrestor. Most of the lower power (and lower priced) strips go with the less expensive varistor (also called an MOV) component.

These components age over time, and suffer varying degrees of damage each time they clamp down on a voltage spike. One big hit will kill them outright. But they can be also damaged, over time, by a series of much smaller hits. And once the damage to the varistor reaches its failure point, the component can fail catastrophically. You might hear a pop, and maybe even get some smoke, or find scorch marks on the casing should that happen. If it does, junk the strip immediately.

Although there is probably some risk of a fire following a catastrophic failure, I wouldn't be overly concerned about that happening. Any surge hot enough to fry your strip, and start a fire, will probably take out your house's service panel and power mains. If that happens, a baked power strip will be the least of your fire risk problems.

Fortunately, most strips don't fail catastrophically. Instead, they fail quietly, and just stop working. At which point, your "super-deluxe computer grade power management strip" becomes nothing more than a very pretty extension cord.

Which brings us to the little power light...

Unless your model has an indicator light showing the status of the surge protection component, you'll have no way of knowing whether or not it is working properly. Not having such an indicator light can be a real problem because it isn't possible to make that determination visually. Better surge suppressors have separate power and protection indicator lights. Some even have additional indicators for missing ground connections and hot/neutral lead reversal problems. If you have a less well engineered strip, all you'll probably have is a light built into the power rocker switch. And from a diagnostic viewpoint, that light could mean anything - or nothing much at all.

What you will need to do is locate some documentation for the strip you own. Each brand does things differently. On some strips, protection is working when a light is on. On other strips, a lit protection indicator means the protection circuit has failed. Browse the manufacturer's site and locate the user guide, or e-mail their tech support people if you can't find anything.

If your strip used to have a lit power indicator, and now it doesn't, something isn't right. It could be something as minor as the neon light inside the switch has burned out. But it could also mean your surge suppression circuit is no longer working. And it could also indicate some other problem as well. I've seen some surge strips have that light come on because of a bad plug ground connection. Try plugging the strip into a different outlet and see if the light comes back on. If it does, you might want to have somebody take a look at the outlet you originally had it in. Surges can damage wall outlets just as easily as they can affect what's plugged into them.

My Dad trained as an electrician when he was in the Navy. He had a rule of thumb for anything that got plugged into a wall:

"When in doubt - have it checked - or throw it out."

Over the years, I've learned that's pretty good advice. :Thmbsup:



« Last Edit: June 15, 2009, 03:41:45 PM by 40hz »

40hz

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Re: is this how you can tell if a powerstrip is bad
« Reply #3 on: June 15, 2009, 03:43:15 PM »
@Hey 4wd!

Shoot. If I knew you were going to write the book, I wouldn't have bothered to write the book! ;D ;D ;D

 :Thmbsup:


techidave

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Re: is this how you can tell if a powerstrip is bad
« Reply #4 on: June 15, 2009, 06:26:18 PM »
Wow, if I knew somebody was going to throw 2 books at me, I may not have bothered to ask the question.   :D

Thank you to both 4wd and 40hz for your very detailed explanations.  Your "when in doubt, throw it out" advise will give me a greater peace of mind.  So far I have found only 4 out of about 20 or so that I am not comfortable with.  For a price of $10 or so apiece, its not worth worrying about.

techidave

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Re: is this how you can tell if a powerstrip is bad
« Reply #5 on: June 15, 2009, 06:27:32 PM »
How about a power strip with an indicator light that flickers constantly?   I plug several others into the same outlet and they don't flicker.  So does this mean there might be something wrong internally?

4wd

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Re: is this how you can tell if a powerstrip is bad
« Reply #6 on: June 16, 2009, 01:13:35 AM »
@Hey 4wd!

Shoot. If I knew you were going to write the book, I wouldn't have bothered to write the book! ;D ;D ;D

 :Thmbsup:

I wrote the abridged version  :P

Quote
"When in doubt - have it checked - or throw it out."

I always preferred: "One flash and you're ash."  ;D

How about a power strip with an indicator light that flickers constantly?   I plug several others into the same outlet and they don't flicker.  So does this mean there might be something wrong internally?

Unless you're prepared to pull it apart and look or fix it, it could mean almost anything from:
a) the filament in the light, (assuming it is filament based), broken and making intermittent contact due to vibration;
b) the neon gas in a neon tube failing to ionise uniformly;
c) the, (omnipresent), voltage dropping resistor breaking down intermittently;
d) dry solder connections causing intermittent connection due to either heating/cooling effect as it makes contact or vibration;
e) etc, etc, etc.

As both 40Hz and I say above, it's your peace of mind at risk.

I'd pull it apart and fix it if it annoyed me enough but considering it would probably be tucked away under a desk or something I'd most likely wouldn't notice it in the first place.  Nor would it bother me if I did notice it, if it was only the light doing it - if it was all the attached devices as well then I'd pull it apart and fix it :)

Spend AU$4-7 versus 20 minutes of my time, I'd keep the money :P

Plus I don't believe in the throw-away society we seem to live in now.

"Pleased to meet you, my wife is called MakeDo, my name is Mend."   :D

Quote
Your "when in doubt, throw it out" advise will give me a greater peace of mind.  So far I have found only 4 out of about 20 or so that I am not comfortable with.  For a price of $10 or so apiece, its not worth worrying about.

Oh, one thing if you're throwing them out: If you don't think they're safe to use then that should apply to everyone else as far as you're concerned.

Before you toss them out, cut the mains lead into 150mm lengths starting as close to the plug and the strip as you can so they can't be used.  This should apply to anything mains powered that you throw out.
« Last Edit: June 16, 2009, 01:44:17 AM by 4wd »

techidave

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Re: is this how you can tell if a powerstrip is bad
« Reply #7 on: June 16, 2009, 02:20:44 AM »
Quote
Before you toss them out, cut the mains lead into 150mm lengths starting as close to the plug and the strip as you can so they can't be used.  This should apply to anything mains powered that you throw out.

I have learned to do this on everything I throw out, otherwise people will dig it out of the trash and try it at home.

4wd

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Re: is this how you can tell if a powerstrip is bad
« Reply #8 on: June 16, 2009, 02:24:57 AM »
Quote
Before you toss them out, cut the mains lead into 150mm lengths starting as close to the plug and the strip as you can so they can't be used.  This should apply to anything mains powered that you throw out.

I have learned to do this on everything I throw out, otherwise people will dig it out of the trash and try it at home.

Just don't do it around my area because I'll be one of those people  ;D