Surge protectors don’t last forever. Like lightbulbs, they need to be replaced every few years when they wear out. Just because your old surge protector passes power to your devices doesn’t mean it’s still actively protecting them—in fact, you probably need a new one. After assessing more than 30 hours of research, and 32 hours of testing by an electrical engineer, we found that most surge protectors that cost just above $20 will provide adequate protection from surges. But our new top pick is the Tripp Lite TLP1008TEL, because it stops passing power when it’s no longer effective at blocking surges.
Most surge protectors rely on an easily ignored LED indicator to tell you when they’ve ceased protecting your gear. We picked the TLP1008TEL because when its ability to block surges wears out, it cuts the power off entirely. So long as your devices are energized, you know that surge protection remains in place and there’s no ambiguity as to when it needs to be replaced. (If you want to protect equipment that will likely be damaged if power is abruptly removed, we recommend an uninterruptible power supply, or UPS. For more details, see Who this is for.)
The TLP1008TEL’s 10 outlets offer enough space to satisfy most home office or media center needs, and provide plenty of protection to those outlets to safeguard your electronics from the most common electrical threats. Even though there are bigger and more expensive surge protectors available, our extensive research and testing showed that they didn’t provide enough additional benefit to be worth their higher cost.
If the Tripp Lite is unavailable, the Belkin PivotPlug is also a capable surge protector and has an excellent design that offers more outlets at a similar price. But, unlike the Tripp Lite, once its MOVs fail it puts your electronics at risk from further surges by providing power even after the protection ceases being effective, which it marks by an indicator LED not being lit (though you might prefer this if you’re plugging in hard drives or other sensitive electronics that you fear might be harmed by a sudden shutdown). With 12 total outlets, the Belkin model includes eight tilting outlets along the sides that allow you to fit all manner of power blocks at myriad angles. It’s as clever as it is useful.
For lighter duty, like under nightstands or side tables, the Accell Powramid D080B-015K is the way to go. It has two USB ports and six outlets in a comparatively small package. The USB ports put out a combined 2.1 amps, enough to charge one smartphone or tablet at high speed or two devices at low speed. The Powramid has a clever-enough design that makes all the outlets usable, even with larger plugs. Despite the silly name, the Powramid packs some serious protection and tested almost as well as our larger pick. To fit that much protection in a small package, Accell used a compact circuit that might not last quite as long, but offers a great deal of protection. Even at this lower price, Accell products safely prevent power from passing through when the protection has failed—you’ll know when it’s time to replace it in a few years.
Tripp Lite’s SpikeCube is perfect for traveling in areas with spotty grids. It covers just one outlet, but has performance comparable to the bigger picks squeezed into a pocketable package. If you want something on the go with more outlets than the SpikeCube and are less concerned with surge protection, check out our full travel USB surge protector guide.
While researching this guide, we found a huge amount of outdated or incorrect information scattered around the Internet. If you want to learn the the facts, the surge explainer at the bottom of this guidewill lay it all out for you. But don’t feel bad if you skip it: We placed it at the end, since you don’t need to read it in order to follow this guide.
Why you should trust us
In order to separate fact from fiction about surge protectors, we reached out to some pros. We talked with Mike Hyland, a 30-year veteran of the utility industry and senior vice president at the American Public Power Association, to learn about power grids and utility-scale surge protection. We checked in with Nick Platsis at Anthem to find out what he uses to protect his high-end A/V gear. We emailed with Jack Loppnow, an insurance pro who has been in the industry since the 1960s, and got advice on what part homeowners’ and renters’ policies play in protecting your technology investments. And after all that, we put our top picks to the test with Lee Johnson, an electrical engineer with more than 10 years of experience designing and testing electronics.
Who this is for
A surge protector offers peace of mind when you’re concerned about sudden power spikes that could fry your expensive electronics. You may live where severe weather regularly causes power fluctuations (though don’t expect a surge protector to help you in the event of a direct lightning strike), or be on an electrical utility’s system that can’t provide good, consistent power. You may also just want figurative insurance—more about actual insurance later—against an unlikely event that requires a small investment to forestall.
Because a surge protector is a “better safe than sorry” device, experts recommend getting one that stops providing power the moment the internal circuitry that protects against surges stops working. For most people, that isn’t a problem, because most modern hardware can cope with the sudden loss of power—and better the loss of a power strip than the destruction of hardware that could cost thousands of dollars to replace.
However, if you have equipment that could be damaged by a sudden loss of power, mission-critical gear that can’t ever go down or needs a specific shutdown or power-up sequence, or even just a desktop computer with a hard disk drive (HDD) susceptible to data corruption in the case of sudden removal of electricity, then you shouldn’t be looking at a surge protector at all. Instead, you want an uninterruptible power supply, or UPS. A UPS is basically just a big battery that you place between your outlet and your gear, and most of them have surge protection built in. You can read about our top UPS picks here.
Many surge protectors keep power flowing when their protection fails and the only way you know that they have failed is if you notice the “protected” LED that should be lit up has gone out or changed color. Because the circuits that protect against surges in affordable power strips have a non-linear failure curve (they’ll die suddenly one day during or after a surge), there’s literally no way for a device to track its own lifespan and know when it will fail. The best estimate available is only the end of an equation that adds up the capabilities of various internal components. This is why a hypothetical smart surge protector couldn’t warn you, even if it had Bluetooth, ZigBee, Weave, or Wi-Fi built-in—or even a bleeping alarm—though it could alert you after it failed.
If you live in an area with a stable power grid and a mild climate, you can probably skip the surge protector without too much risk. That’s what Nick Platsis, product manager at Anthem AV does, and Anthem makes receivers that can cost into the five figures. Ultimately though, the low cost of surge protectors makes them worthwhile for a vast majority of people looking to stave off this one type of catastrophe.
How surge protectors work
It’s easy to pick surge protectors based on the number of outlets or a snazzy design. But without reliable protection, all you have is a power strip. All power strips offer are more outlets, while a surge protector is first and foremost a safety device that also has extra outlets. It treats out-of-control electricity like a runaway truck ramp on a mountain road, diverting it before it crashes into your TV, computer, or other pricey piece of equipment.
Instead of water barrels or piles of sand, a surge runs into a series of metal-oxide varistors (MOVs). These components sacrifice a little of themselves each time they take a hit, and how much they can take over their lifespan is expressed as the joule rating of a surge protector. Many small hits—or one giant one—reduce or eliminate a surge protector’s effectiveness.
The better the MOVs are and the more that are crammed inside, the longer it should last, but make no mistake: Surge protectors don’t last forever–they’re consumable devices, like lightbulbs. But most people don’t know that, because they’re typically not marketed or explained that way. That gunk-covered surge protector you bought at a Circuit City years ago? It probably isn’t providing any protection at this point, even if it does supply power.
If, like our top pick, your surge protector safely shuts down (forever) once it’s protection capabilities have been expended, then you don’t have to worry. Just replace it when it stops passing power. If not, replacing your surge protector every three to five years would likely be on the safe side in most areas. If you experience a major blackout, utility problem, or natural disaster, consider replacing your surge protectors as soon as possible.
MOVs are worn away slowly by many unnoticeably small surges over time, and the more worn they are, the smaller a jolt needs to be to burn them out completely and deal a death blow to your sensitive electronics. So if you haven’t been replacing your surge protectors regularly, you may still be just one big jolt away from frying your TV. The number of hits your protector can take before dying is loosely correlated with its joule rating. Indeed, if you’re staring at a shelf full of surge protectors, the marketing departments would have you choose based on this figure alone. This seems like a really concrete measure, but buying a surge protector based on nothing but the joule rating is like buying a car based on nothing but the horsepower. And unlike clamping voltages and response times, which are tested and certified by the independent labs at UL, each manufacturer is allowed to calculate joule ratings in its own way.
Electrical components also have variable tolerances—they’re not manufactured to exact specifications, but to function with an acceptable range. For instance, when our electrical-engineering consultant, Lee Johnson, opened the Tripp Light and examined its varistors, he found the components are designed for a 10 percent tolerance above or below their rated clamping voltage. “That means a 330-volt UL-rated unit could test between 363 volts and 297 volts coming out of the manufacturer,” he said.
How we picked
In choosing which surge protectors to bring in for testing, we examined and disregarded a lot with common features that we found would add no value at all or add very little, or which cost far too much relative to the benefit for nearly everyone.
Many home office and home theater surge protectors come with ports that promise to protect your cable or phone lines, but we feel comfortable without them on our main pick. While phone and cable lines certainly can carry surges into your home, many technicians and Internet providers discourage running data lines through surge protectors because, they say, it can introduce noise and degrade performance—a claim we weren’t able to prove or disprove. Our testing and teardowns showed many manufacturers put wimpier protection (if any at all) on these auxiliary ports, so skipping them probably puts only a slight risk to your modem or cable box.
Noise filtering is a common “premium” feature on the more expensive surge protectors that we tested in last year’s guide, but since most models performed similarly, we didn’t test it on this year’s models. In any case, all power supplies, whether internal or external, have noise filtration built in—in most cases, enough already to prevent any noise coming in on the AC line from interfering with the operation or performance of your electronics. Noise filtration probably isn’t something you need to worry about unless you’re having some sort of noise problem (usually manifested as static) in your audio or video gear or computer peripherals.
While many surge protectors are sold with “connected equipment coverage,” we didn’t consider that in making our selections. We suggest you read the fine print, since often you’ll have to leap through a bunch of hoops to collect in the event of disaster. If you want financial protection you can count on, don’t get it from a tech manufacturer. Just make sure you’re covered by your homeowners policy or renters policy.
“Both homeowners and tenants policies cover losses caused by lightning up to the limits of the policy,” explained five-decade insurance veteran Jack Loppnow in an interview. Loppnow currently works in the Milwaukee offices of insurance broker Robertson Ryan & Associates. He cautions that you shouldn’t assume you’re covered just because you have a policy: “Many companies exclude loss to tubes, transistors, electronic components, or circuitry that are part of appliances, fixtures, computers, home entertainment units, or other types of electronic apparatus.”
Whether or not you’re covered by your policy or common riders that are added to protect your home’s contents will depend on your policy and local insurance conventions and regulations. Because there are so many variables, Loppnow advises that you double-check that your electronics are covered, and he added, “It is always a good idea to have receipts from the purchase of the items damaged.”
If your home theater costs more than a compact car, then series mode protection may be worth investigating, but the technology isn’t worth the huge price tag for most people. These surge suppressors are made by companies like Brickwall and Torus Power, and came on the market much more recently than the MOV-based protection that we considered. Series mode protection is superior to MOV-based protection on pretty much every point. Except for one big one: cost.
It would cost more than 10 times as much to replace our MOV-based pick with a similar number of series mode protected outlets from a reputable manufacturer. While the series mode protector will theoretically pay for itself after 30 to 50 years (depending on how surge prone your abode is), the upfront cost is simply too high to bear for most people. It’s not worth it for most people to spend $300 on a device to protect $2,000 worth of equipment from a rare disaster scenario. We think it makes more sense to spend roughly $20 for a device that stops passing power when it’s kaput and replace it every few years.
It’s also worth noting that most information touting the benefits of series mode protection is written by engineers or executives from the companies that make the products. If you jump into our deep dive on surges below, you’ll find that our research shows that small surges are less of a risk than they used to be, and the biggest surges—like lightning—are too huge to be controlled by any type of plug-in style device, whether MOV-based or series mode.
Once we had a good idea of what we could leave out, we wanted to find the contenders most likely to meet most people’s basic needs—based on factors like outlet count, outlet spacing, and cord length—before moving on to test their protection. To that end, we surveyed 835 of our readers to learn about their expectations and narrow the criteria. For everyday features, our survey responses showed similar results for home theater and home office use.
A majority of respondents have six to seven devices plugged in, but wanted between eight and twelve outlets if purchasing a new model. This let us rule out most models with fewer than 10 outlets. And since 70 percent of respondents would spend up to $50 on a new model, we used that as our price ceiling. Anything more expensive offers extra protection that most people don’t need, or extra features like network protection outlets that most people won’t use. For offices and home theaters, features like USB outlets are less important than designs that accommodate bulky power supplies. Ultimately, a surge protector needs to be capable, so we reached out to the manufacturers to verify clamping voltage, response times, and failure behaviors on top models. This left us with three models that we called in for testing.
For lighter-duty use, 54 percent of our survey respondents wanted a surge protector in the bedroom. Since most of those responses indicated just three or four devices in use and the desire for a couple more, we focused on units with six outlets that sell for less than $30. The smaller, lower-powered chargers used in a bedroom are less likely to have huge power bricks, so outlet spacing is less important than useful perks like USB ports. Once we checked the protection claims with the manufacturers, we brought in our three favorites to test right alongside the larger candidates.
Our final test list comprised the Belkin Conserve, the Belkin PivotPlug 12-Outlet BP112230-08, the APC P11VNT3 3020J 11-outlet SurgeArrest, the Tripp Lite TLP1008TEL, and the Tripp Lite Isobar HT10DBS for office and home theater use; and the Accell Powramid, the Accell Power Genius, and the Belkin PivotPlug 6-Outlet for bedroom and light-duty use.
How we tested
Electrical power supplied through a standard residential outlet uses three wires: line (or “hot” or “live”), neutral, and ground. AC power comes in via the line wire, passes through a device that uses power, and “returns” through the neutral, forming a complete circuit. The ground wire serves to drain excess potential energy and protect against electric shock when there’s a wiring fault in a powered device of any kind. (Modern two-prong devices are heavily insulated against shorts, and typically use polarized plugs that have one blade larger than the other, so that they can only be plugged in with the line and neutral connections in the right place.)
Devices use AC power by making connections between these incoming wires; we call these combinations the “legs” of a circuit. Line-neutral, abbreviated L-N, carries voltage in normal conditions. But line-ground (L-G) and neutral-ground (N-G) can also carry power during surges or with faulty equipment. Surge protectors have separate circuits that protect each leg, sometimes in substantially varying amounts.
Lee Johnson, an electrical engineer with more than 10 years of experience, help set up our testing parameters and meticulously dissected our units for comparison, simulating surges and analyzing the results. He relied on a Solar 7054-1 600V Transient Spike Generator and ATTEN ADS1062C Digital Oscilloscope to inject spikes into each surge protector on each leg. He tested using a series of surges, from 100 volts through 600 volts at 100-volt increments until the surge protector began restricting or “clamping” the voltage. He repeated testing at this clamping voltage five times for each leg on each unit and recorded the whole process. We followed the same procedure on auxiliary ports for cable and phone, though starting at zero volts.
The difference between the ostensibly top normal AC voltage of 170 volts and where clamping begins (at 330 volts or higher) is called the “let-through voltage,” and that is our baseline for comparing surge protector performance. If a protector clamps voltage exactly at 330 volts, the let-through amount would be 330 minus 170—that’s 160 volts. The real-world let-through voltage we tested has a direct impact on how much damage electronics might incur.
Whenever we refer in this guide to let-through voltage on AC power legs, we’re using the voltage above 170 volts for consistency, including in our charts. With auxiliary ports, where clamping should be at zero volts, we subtract nothing. We didn’t want to see more than 160 volts in net let-through voltage.
We often rely on UL’s certification, and all the devices we picked have passed UL testing. However, UL certifies surge protectors at multiple levels, and some, like the Tripp Lite TLP 1008TEL, are certified at a less stringent 400-volt let-through rating. Tripp Lite’s own specs for this model, however, list 150 volts of let-through (320 volts total) as its actual clamping voltage level, and we were able to confirm that in testing. While we’d prefer the UL rating to be in line with the claimed clamping voltage, we’re comfortable that our testing confirmed it. The other picks all have a 330-volt UL rating.
Surge protectors also can put different amounts of protection on each of the legs we described earlier. Some have designs that put the highest protect on the L-N leg, the most likely path to damage equipment as it passes directly through the transformer or motor of a powered device.
In our chart, we show let-through voltage for each of our picks Johnson tested and across each leg. Both the best and the worst let-through performance came from Belkin, with its 12-outlet PivotPlug letting through just 126 volts of the surge and its remote-switch-equipped Conserve (not picked) allowing 190 volts through. Our top pick, the Tripp Lite TLP1008TEL, was in the middle, letting through 142 volts on the L-N leg.
We found the largest differences in protection on the N-G leg, where the Accell unit allowed 204 volts through but the Isobar only let through 104 volts. Of nine models we put through our tests, not a single one stood out as consistently the worst or the best on all branches.
Four of our tested units had auxiliary ports, which should let almost no power through above 0 volts, but only the Isobar’s telephone and Ethernet ports had real protection: those ports blocked 90 percent of a 600-volt spike. When we sent the same spike through the coaxial ports, they were basically unprotected, allowing 570 volts through. The APC Surge Arrest, on the other hand, let just 52 volts through on the coaxial line, but offered no protection on the telephone lines. Some manufacturers claim only to “filter” these ports, others claim to protect them. But the difference is often not clear, and the protection wasn’t consistent in our tests. Thankfully, while surges are possible on auxiliary lines, they’re far less common than on electrical lines.
Results of Let-Through Voltage Tests (Above 0 Volts) on Auxiliary Ports
|APC SurgeArrest 3020J||52||600||N/A|
|Tripp Lite TLP1008TEL||N/A||600||N/A|
|Belkin 12-Outlet PivotPlug||525||N/A||N/A|
In addition to our bench tests, we took into account Johnson’s feedback after he tore apart our top performers. The Tripp Lite and last year’s pick from APC had identical varistor components in slightly different configurations. And just like the more expensive Isobar unit, they all use the same diameter wiring—14 AWG—and they all have current limit fuses and filtering capacitors on the incoming AC line.
The differences are mostly in how the components are used. For instance, both the APC and Tripp Lite units have eight varistors, but the APC unit has 3 on the L-N, 2 on the L-G, and 3 on the N-G leg, while the Tripp Lite distributes them in a 4, 2, 2 configuration. The Tripp Lite model puts 200 V varistors on the critical L-N leg with two 470 V as backups after those burn out.
Overall, the APC had a slightly more robust design, but the differences weren’t glaring, nor were they decisive in light of its less-than-stellar performance in testing. Comparing photos from the last teardown, we didn’t notice any major component changes in the APC from year to year, so we can only attribute the drop in performance to our test unit being on the opposite side of the manufacturing variances this time around.
If you spend a lot more on the Isobar unit, you will get some internal upgrades, like 10 varistors that are each rated for double the voltage of the eight varistors in our picks, and larger capacitors and inductors on the incoming AC line, which provide greater noise and voltage suppression. Since our tests didn’t show a huge gain in performance when hit by individual surges, we suspect that the Isobar may keep protecting you for longer, but it isn’t necessarily better on a per-surge basis. Because the Isobar units tend to cost more than twice as much, we’d only recommend them if we could confirm they last twice as long, which requires extremely long-term testing.
Best for home theater and office
We picked the Tripp Lite TLP1008TEL because it offers plenty of outlets for most applications, provided solid protection in our testing, and, most important, has the safest failure state of the top candidates.
Most surge protectors continue to provide unprotected power to your connected electronics after their components are no longer capable of blocking a surge, but they give little warning when they do this—an LED may either light up or go dark. Instead of putting your gear at risk, the Tripp Lite safely shuts down all power, letting you know it’s time for a replacement. This might be inconvenient on the day it fails, but the situation is better than finding out your surge protector failed only after your home theater has taken the hit. (If you really need enough continuous power to shut down equipment after the surge protection fails, consider a UPS, which we discussed earlier.)
The Tripp Lite had the most consistent performance on all our tests when clamping surges. When testing let-through voltage, it was at or better than average on all three circuit branches. It shares many of the same components with our prior pick from APC, but arranges them in a slightly different design. It also adds two filtering capacitors on the incoming AC line along with additional voltage-suppressing varistors and current-limiting fuses.
The biggest drawback to the Tripp Lite is the lack of rotating or tilting outlets—you get only four of the 10 outlets spaced out well enough to fit large power supplies. Overall, though, it has enough for most theater and office setups with an outlet or two to spare.
Best for light duty or small spaces
We like the Accell Powramid for light-duty use around the house, even if we hate saying the name. Like our top pick, the Powramid safely shuts down power once its protection is expended, so you won’t put your electronics at risk and you’ll know when it’s time to replace it. In our tests, the Powramid had the most consistent let-through voltage of any of the smaller candidates, averaging 152 volts. The Powramid uses a three-phase varistor design that covers all three legs of the circuit, which is how it achieves its compact size and impressively consistent performance. However, it won’t last quite as long as bulkier, multi-varistor designs.
The single varistor is also what’s responsible for the near-identical results across all three legs—154 V, 152 V, 152 V. While the other candidates didn’t fare much worse on average, their results were never quite as good, and not nearly as consistent. While Accell’s Powramid varied by less than 2 volts from leg to leg, the company’s PowerGenius Rotating 6-Outlet Surge Protector (with a traditional multi-varistor layout) varied by 74 volts with a 130-volt let-though on the L-N leg and 204 on N-G. The shorter life of the single varistor in the Powramid is a fair trade for strong, consistent performance in such a small package.
The Powramid’s unusual design is actually useful, instead of just a gimmick. All six outlets are spaced and angled in such a way that you could comfortably plug power bricks into all of them at once. Further, it has two USB outlets so you can charge your phone or tablet without needing a power adapter at all. The only flaw in the design is the small plastic cover over the power button that seems made to be lost. But the cover is a bit superfluous anyway, so it’s not a dealbreaker if it disappears on day one.
Best portable protection
The Tripp Lite SpikeCube is the best protection you can get in a tiny package. It doesn’t have a cord and protects just one outlet, but that makes it perfect to plug in behind an appliance or to keep in your bag for when you need to plug your laptop into a strange outlet.
We put the SpikeCube through the same tests as its larger counterparts, and we saw impressive results for such a diminutive gadget. Its clamping voltage across the three legs was just 138 volts, 166 volts, 156 volts—second best on the L-N and N-G lines, and second overall when compared with the other four light-duty surge protectors we tested.
Inside, it’s a simple device. Its protective MOVs are about half the size of the ones we found in larger units, providing similar voltage protection but rated to last about half as long. A pair of them protects the main L-N line, and the L-G and N-G lines each get their own. While our engineer did find a noise-filtering capacitor on the incoming power line, he noted that it was substantially smaller than the one on the Tripp Lite 10-outlet model.
Even though there are sacrifices in longevity when you get a surge protector this small, it will still protect your devices from surges as well as units that are much larger and much more expensive.
For those worried about sensitive electronics
If you want your surge protector to continue passing power even after it has failed (say you have it connected to a device with a hard drive that you don’t want to risk damaging with a sudden shutdown), then we recommend the Belkin PivotPlug 12-Outlet Surge Protector. Even though it will supply power once the protective MOVs have worn out, it provides above-average protection in an innovative package. You’ll just need to check the LEDs on occasion to make sure it’s still working, so it’s not a great pick if you plan to use it behind a media center.
Our tests showed that in normal use the Belkin’s protection was as consistent and as good on average as our top pick—they both averaged 133 volts across all three legs. That’s likely because each leg uses identical three-phase MOVs, similar to the one inside our other pick, the Powramid.
We especially like Belkin’s unique pivot design: Eight of the twelve outlets along the side can rotate up to 90 degrees away from the top plane of the device toward the side. This feature makes it easy to plug power bricks into all eight pivoting outlets, alternating each brick’s angle. We tested Belkin’s six-outlet version as well, which has the same great design, but since it lacks the stopping power of the bigger unit, we aren’t recommending it. Anyone who needs the power-after-failure state and lots of outlets will get a lot of value from the Belkin PivotPlug 12-Outlet.
All about surges
If you’re going to obsessively evaluate surge protectors, you have to know a lot about surges. Unfortunately, a lot of the information out there is outdated, unsubstantiated, or just plain wrong. There are a few different types of surges that threaten your electronics, some from the grid, and (maybe) some from inside your house. Technically, “transient voltage” is the proper shorthand for the phenomenon we’re talking about, but because “surge” is the more common term, we’ve used it throughout this guide for better readability.
Surge-protector marketing may try to persuade you to fear “inductive kick,” a common surge that can be created by motorized appliances right inside your home. But it’s not a reasonable concern in modern times. There are a few different ways inductive kick can come into play; our electrical expert, Lee Johnson, explained possible test scenarios:
All appliances with a motor have inductive kick when they are shut down. This is from the motor windings acting as an inductor, which are coils of wire, storing energy in a magnetic field during operation. When power is removed, the field collapses and a voltage spike is generated. To prevent this spike from exiting the unit or damaging internal circuitry in the appliance or making undue electromagnetic interference, snubber components are placed across the motors. These snubbers redirect the voltage pulse and bleed it off safely.
e asked him to do a quick investigation, and even after plugging his oscilloscope into outlets shared with a residential refrigerator, a 1980s mini-fridge, a washer, a microwave, and a ½-horsepower stationary belt sander, he couldn’t detect anything greater than 2 volts above nominal AC voltage. As a phenomenon, we know that inductive kick exists, and it may be a common threat in industrial settings or anywhere else that relies on three-phase power, which isn’t used in home settings. But we’ve been unable to find any independent research quantifying it as a residential threat, and since we didn’t find it in our own investigation, we’re not so worried about this as a common cause of surges in your house.
Casual conversations about surges and electrical safety often jump right to lightning. It’s the flashiest threat, conjuring up images of exploding transformers and outlets bursting into flame. Lightning is a threat to most electronics, but probably not in the way you imagine. Household wiring in the US is designed to carry 120 volts on average. Lightning can pass millions of volts. No surge protector is going to save your TV if lightning strikes your house or wiring directly. “I don’t care what you have for a TVSS [plug-in surge protector], it’s blowing out your computers,” Mike Hyland, senior vice president of engineering services at the American Public Power Association, told us during an interview. The best you can do if you’re worried about a direct lightning strike (perhaps during a violent thunderstorm) is to unplug any valuable electronics, and make sure you’re properly insured.
Compared with the catastrophe of a direct strike, damage from a nearby strike might be preventable. But in this case, your surge protector isn’t the first line of defense—it’s the last. Hyland told us that aside from protecting customers, utility companies have a huge financial interest in preventing surges from any source. While your media center might cost $3,000, utility installations can quickly run into the millions.
To dissipate nearby strikes, utilities install lightning arrestors, “typically at every transformer where we’re going to feed a customer. … If a lightning strike hits the high side line … it will hit that lightning arrestor and not go through the transformer.” Utilities also protect those transformers with huge bay-o-net fuses and all manner of relays, breakers, and fuses, including huge current-limiting fuse canisters, filled with wet sand and 2 feet or longer, in areas where dangerously high currents are a risk. “What they do,” explained Hyland “is, as the current starts to rapidly increase in a situation where … a lot of joules are coming through that line and it’s going to be destructive, that sand actually turns to glass as the metal melts. So your fuse is melting, it’s causing unbelieveable amounts of heat because it’s happening so rapidly, and … what you end up with is a 2- to 4-foot length container of glass and that’s your bridge between the high side and the low side.” (Glass is an insulator—non-conductive.) Once the fuse has failed, a door opens and can be spotted from the ground during inspections.
All that fancy utility company equipment that helps protect against lightning strikes also smooths things out for more common occurrences. Power companies are constantly monitoring use in their service area and bring more power online to cope with peak demands, or switch sources for greater efficiency at an off-peak time. This switching can cause surges in the grid that are just as problematic as lightning. Grid surges can also happen before or after blackouts, which is related to why you sometimes find breakers flipped when the power comes back on. And sometimes grid surges result from simple accidents like storm damage or a car hitting a utility pole.
By the time a surge reaches your house, all those utility protections should have made it more manageable. Homeowners can opt to install a whole house surge protection device (SPD) that works in a similar manner to plug-in surge protectors, but provides protection at the service entrance. Hyland told us that this was actually an option pitched to people by utility companies in the 1980s and ’90s in an effort to increase revenue, but fell out of favor when the companies made investments in other areas. Estimates to purchase an SPD range from $500 to $1,000, and an electrician would need to install it, assuming your home electrical panel and service from the utility are modern enough to wire it in.
We researched readily available whole-house SPDs, and they are typically rated at a much higher let-through voltage, clamping at 600 to 1,200 volts (a 430- to 1,030-volt let-through), depending on the device and the leg, which is two to four times higher than our picks, which mostly clamp voltages at 330 volts or less (160-volt let-through). As a result, even if you installed a first line of defense with a whole-house SPD installed, we still feel you need surge protectors for clusters of or individual devices. If the surge from a nearby—but not too nearby—lightning strike still has juice left after passing through multiple layers of protection from the utility company and a whole house surge protection device, then it should be something that one of our picks can handle.
Johnson didn’t test specific equipment in this category, but suggests that only people who live in areas at high risk for routine surges, line downings, and other problems should research this option. These SPDs can also prevent damage to ground-fault protection circuits, refrigerators and other appliances, table lamps, incidental electronics, and and other equipment that isn’t sensitive to surges at the same level as computers and A/V equipment.
A good plug-in style surge protector should be enough to keep your electronics safe past where the utility has invested in keeping its grid safe. However, if worst comes to worst—again, you should have insurance. Hyland noted that a utility will pay out of pocket only on claims that are due to its negligence.
While Hyland said he uses surge protectors in case of a not-too-distant lightning strike, we also spoke to Nick Platsis, the product manager at Anthem, producers of premium A/V equipment. In his house “Everything is plugged into the wall except computers on battery backup.”
Care and maintenance
Whether old or new, there are a few basic guidelines that will help ensure that your surge protectors are and remain effective:
- Never plug one surge protector into another surge protector to add outlets. This is an easy way to exceed the current ratings on the surge protector, and even the wiring in your walls. The best case scenario is you trip a breaker or blow a fuse. The worst case scenario is something starts melting—that’s the opening act for an electrical fire.
- Never plug a surge protector into an ungrounded outlet using a three-prong to two-prong adapter. Bypassing the ground will render many of the benefits ineffective because two-thirds of the varistors are often tied to the ground leg. (Also, don’t mess with the wider blade on a two-prong plug: It’s polarized to fit in only one orientation in an electrical outlet to ensure line and neutral voltages pass through the correct prongs.)
- When you first plug in a surge protector, be sure the status lights don’t report any problems: Most protectors have a single grounding light, which indicates whether there’s a ground fault. If it shows there is one (typically by being unlit), that’s a reason to call an electrician as soon as possible to determine whether you have a wiring problem. A ground fault is a risk to your devices, health (electrocution), and safety (fire).
- Always replace your surge protectors after any large event (lightning strike down the block, multiple outages in rapid succession), or if they show any signs of damage or burn marks.
- If your protector delivers power even after its MOVs have failed, plan to replace it anytime you have a major electronics upgrade, or at least every three to five years. Our pick avoids this, since it stops working when it wears out.
Last year’s pick
The APC P11VNT3 SurgeArrest 3020J was our previous pick for the best surge protector that supplies power even after the protection has been expended. However, we no longer recommend it for that purpose, as it behaves in a way that doesn’t match our criteria. In short, although we still consider it a good surge protector, you may want to replace it if you purchased it believing it wouldn’t cut power in the event of its protection failing.
Following feedback from a reader, we followed up directly with APC about how the unit behaves once its MOVs have exhausted their ability to block a surge. We found that the device’s published specs contradict its manual, and neither correctly describe its behavior: The specs say it cuts off power; the manual says it passes through power.
In truth, it does both. After the MOVs are fried on the main L-N leg, the most crucial power path, the APC will cut power. But if either the L-G or N-G legs’ varistors burn out, power continues to flow. This isn’t optimal since the device may well leave your sensitive electronics without power—contrary to the reason we’d recommended it.
Given that, it wasn’t in the running for either our best pass-through or shut-off pick. And its plug layout isn’t as useful as the Belkin PivotPlug for anyone trying to fit a handful of power bricks onto one device, which excludes it on ergonomic grounds.
In this year’s testing, we also found a newer unit tested worse than last year’s, and in fact placed last in our let-through voltage tests. The margin of error in components, however, is wide enough that we wouldn’t necessarily dismiss it based on results from a single model.
We tested the Belkin Conserve because we liked the remote power switch to shut off phantom loads—small amounts of power being pulled by supposedly shut-down devices—on six of its eight outlets. It performed worse, however, than the three other compact surge protectors we tested despite costing a few dollars more. In long-term testing since our last update, the remote switch has proved unreliable and sometimes doesn’t respond even after multiple toggles.
The Tripp Lite Isobar HT10DBS costs more than twice as much as our picks, so we tested it to see what kind of protection you get for the extra money. In our 600-volt test, the Isobar still let through 144 volts, 158 volts, and 104 volts on the L-N, L-G, and N-G legs, respectively. Overall, this wasn’t that different from more basic devices. When we tore it open, we found a few more (and slightly bigger) varistors, along with some upgrades to line filters and related components. In total, the upgrades that you get with the Isobar should make it last longer, but we’re still not convinced it’s worth an extra $50.
We tested the Accell PowerGenius Rotating 6-Outlet Surge Protector with Dual USB Charging with our compact group. It tested well on the main leg with 130-volt L-N let-through voltage, but had worst-in-class protection on the N-G leg with 204-volt let-through. Overall, it didn’t offer much better protection than our preferred model from Accell—the Powramid—and the PowerGenius design is much less useful. Outlets have to be rotated a full 90 degrees to work, and many average-sized plugs will easily block the rotation or simply won’t fit when the outlets are twisted in certain configurations.
We like the design of Belkin’s PivotPlug series, which is why we picked the 12-outlet model as a runner-up. We also tested the six-outlet wall-mounted version, the Belkin BP106000 PivotPlug Surge Protector. Despite being in the same family, the underlying protection is very different, and it ranked third of the four compact units we tested. It’s well reviewed on Amazon, and priced around $5 less than our pick, but we feel the lesser protection isn’t worth the discount.
We planned to test the 10-outlet Accell GreenGenius D080B-003K, but it was discontinued before we we could get a model. The eight-outlet version, D080B-017K, has similar specifications, but lacks both the 10 outlets we were looking for at a minimum, and has a slightly lower joule rating.
The Belkin BV112234-08 12-outlet Surge Protector is top rated on Amazon, and has 12 outlets, auxiliary protections, and an eight-foot cord. But we didn’t test it because the design lacks the notable features of our pick from Belkin and doesn’t offer any more useful protection.
We dismissed the Belkin SurgePlus 6-Outlet Wall Mount Surge Protector with Dual USB Ports before testing because it’s priced similarly to the PivotPlug model, and the PivotPlug’s design is much more useful. It has two USB ports, but so does our pick from Accell, which also fits more power bricks. The SurgePlus’s conventional design of two rows of three outlets is much too cramped to adapt to changing needs.
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