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Do surge protectors actually work?

3K views 24 replies 11 participants last post by  imautoparts 
#1 ·
I've had surge protectors on my computers for years - you know, the kind you buy at Home Depot for about $20 with 6 or so plugs for power and computer cables.

We live in a lightning prone area and many, many times we have lost power and had nearby transformer strikes.

Never, not once, have any of my 5 power surge protectors required resetting.

Do these things actually do anything?
 
#8 ·
Cheap disposable surge protectors are a handyman level type of protection, so don't expect complete and utter protection under all conditions.

It is a very complex area with many variables to consider,
So for the highest level of protection all these need to be considered,
And then the most appropriate type of protectcan be employed,
This would require an experiencd electrician looking at what you want to
protect, and your electrical instalation, and it's grounding system.

Beleive me ! it really is that complex !
But some basic level of protection is better than none !
 
#9 ·
Yes....it is complex.....that why I said that if you wanted to have perfect protection...the cost of the gear would be more than the electronics in the house.

In real terms, the most you can hope for is protection from typical transients. That would be a whole house SPD on the load center and then individual SPD's at the point of use. Anything more than that and the cost goes up considerably.

If you have a central 'data center'...you know, router, server, TV and like....a properly sized UPS might give a bit more protection. A big enough transient to take it out should be stopped right there saving the other stuff.
 
#2 ·
Yes they do....one time.

The cheap ones you have use MOV's. They are typically a one time use device is the surge is big enough.

http://en.wikipedia.org/wiki/Varistor

Surge protection is one of those hotly debated subjects....I would suggest doing a search on grounding before you start asking questions. It's been discussed several times and more than once led to someone getting a timeout.

If you are really concerned....maybe consider adding a surge protector at your load center and replace all your old outlet strips with new ones. One of the issues with those cheap outlets strips is that there is no way to tell if the MOV is still good.
 
#3 ·
To add to DDawg's post

It is possible to buy high quality SPD (Surge Protection Device) with indicator of their operation. I have seen small power strips blown up as they did their job and I have seen many large commercial SPD have one or more of the phase devices blown apart.

An SPD can blow after a large impulse or may blow after many smaller impulses.

Multi level SPD offers the best protection at your panel any sub panels and at the point of use.

If you install a SPD at the main service the best option is for a plug in type, looks like standard circuit breaker. If you install an external SPD keep the leads as straight and as short as possible.
 
#4 ·
Adding to what KAL said....

I personally like the external types that connect to one of your circuit breakers....unless you have the empty slots....then go with the plug in type. Cleaner.

When you use the external type, you typically connect it to a large breaker...say 50A (or what ever the instructions say). That way, if you have an event where the impulse current is greater than what the breaker can take...breaker trips.

But not all is lost. In most cases, the magnitude of the impulse has been considerable dampened and the breaker protects the SPD for another event and tells you that you had an event. Of course, you also have secondary SPD's at the point of use. Right?

If your house takes a direct hit....there is not a whole lot you can do to save everything. Unless you want to install some aviation quality hardware.....which is going to cost more than all the electronics in your house.
 
#5 ·
Hmm.

I wonder if I shop hard maybe I can find a reasonably priced SP that will at least alert me to "events". The advice about replacing my array of 10+ year old SP's sounds like a good idea.

Regarding the ones that fit into the breaker box - sure, I have four or five open slots. Won't that just protect one circuit though? My electronics are on five different 20A circuits.
 
#6 · (Edited)
Either way you do it, they protect each leg. The best ones are the ones that fit between the Meter and Meter pan. As for the externals like Intermatic, they use a 20 amp breaker.

I have a Levitron Surge outlet for my power vent water heater & furnace connected on the load side of the outlet, so that I have those two protected.

As for power strips, I have everything in my house on Surge strips, and networking gear downstairs on a APC UPS, so that I have my U-Verse Gateway online when power goes out.

For incoming telephone, satellite, catv, antennas, Internet, you can purchase the L-Com Lightening protection for those devices.
 
#7 ·
I've been curious about this as well. Also they make whole house protectors, but those actually arn't even inline with the main feed, they use a breaker. I really don't know how those can do anything if they can't temporary cut the power to the rest of the house upon a strike.
 
#10 ·
I've been curious about this as well. Also they make whole house protectors, but those actually arn't even inline with the main feed, they use a breaker. I really don't know how those can do anything if they can't temporary cut the power to the rest of the house upon a strike.
In line surge protectors are made (or were I have not seen in years) but are very large devices and were very expensive. Most all new SPD's we see are the type you describe they work because the impedance across the SPD in very low at high voltages. They have a voltage rating where the SPD goes from being basically an open to closed as the surge/transient exceeds the voltage level.

Good high quality SPD's such as we see in hospitals, data centers and government installations are in the $12,000+ range.

In addition they typically utilize multilevel SPDs with different ratings as they get further from the main service.

http://www.tnbpowersolutions.com/current_technology
 
#20 ·
The intermatic IG1240RC3 is what I have in my house. It is a whole home SPD for less than $150. Like mentioned before, it connects to a breaker in your electrical panel. Along with surge plug in strips that's about the best protection you can get without spending a ton of money. However, the device should be installed by a licensed electrician just to be safe.
 
#21 ·
The device you mentioned, is allowed to be installed by the homeowner in most areas. Yes having a licensed electrician install it, should be done by those people that are not comfortable with working around electricity, or physically not capable in performing the work.
 
#24 · (Edited)
They might be non-functioning but you also don't complain of equipment failure. But these strikes may have shortened the life of your stuff.

You can check protectors with a curve tracer but a 240vac source and a high value resistor may do you as well. The resistor changes the voltage source into a current source.

http://www.google.com/search?client=safari&rls=en&q=isokeraunic+level+map+us&ie=UTF-8&oe=UTF-8
Your location is not exactly a hot spot. FL and the Ozarks are the worst and the FL power people had a pretty good deal for their customers. IIRC, they also publish the specs for their protectors; voltage, current, reaction time, energy absorption.
The Grainger catalog is also good for showing actual numbers, rather than adjectives, if they carry these things.

In any case a considerable chunk of the cost of these things goes into insurance coverage for when they fail to protect.
 
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