Slashdot Mirror
Ask Slashdot: Best Option For Heavy-Duty, Full-Home Surge Protection?
First time accepted submitter kmoser writes "Like most people, I have a couple of surge protectors for sensitive/important electronics, and even a UPS for a couple of items like computers. But I don't have surge protector on all outlets, and these consumer-grade devices don't cover things like 220 volt appliances. Add to that the fact that I live in a lightning-prone area and it's only a matter of time before one of my expensive devices has a major meltdown. I've looked into full-home surge protectors that install next to the fuse box but the prices vary widely and I have no idea how reliable they are or what brands are good. An electrician friend tells me they can still blow out, and when they do they're difficult to replace if they were installed behind a wall. Can anybody shed some light on the best options for protecting all the electronics in my house with a single surge protector?"
You're confusing current and voltage. Fuses and breakers are over-current devices, Transient Surge Suppressors are over-voltage devices. A high voltage at low amps can destroy all the electronics in the house without tripping a breaker or burning a fuse. The only thing that over-current devices protect against are short circuits in devices or in wiring, or excessive load that might overheat wiring.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
They get installed inline with the main house circuit breaker panel. Expensive.
Most people budget for the $$$ for the device. Then they forget the labor to do it right, and always forget to spend the $$$ for a good ground connection.
"Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
I have a surge protector connected to my power meter and the power company even guarantees your appliances against surges. Here is a link to FPL's "SurgeShield"
Effective lightning protection is layered. The socket surge protectors are actually meant to be used in combination with the other layers, not standalone. A close enough lightning strike will induce strong currents in the wiring between the fuse box and your appliances. The surge protectors are designed to protect against the resulting voltage and not much more, and obviously a central surge protector can not protect your appliances if it's not between the surge and the appliance. Stronger surges from lightning strikes into the power lines outside your house on the other hand will not be stopped by the small surge protectors alone. You need both. And then you'll also want a lightning rod to prevent direct strikes into your wiring, because no surge protector would be able to handle a direct strike.
We've got an observatory on a hill with air cabling and plenty of lightning. Our three-stage
protection has never failed through the power line. DSL connections have died many times through the
telephone lines.
First line of defence are large MOV devices with separate grounding installed at the nearest pole. Cost about 600USD.
Second line is at the breaked boxes, cost 400 USD.
Third line is done with 'normal' plug-level protectors for the most sensitive equipment.
Google for Phoenix Contact surge protection..
Unless your dealing with medical equipment or servers don't bother with some expensive custom solution.
This isn't an expensive custom solution. It's becoming more common in new construction. Home Depot has several models to choose from, some as low as $30.
The question is, how good is it?
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
Not at all. Parent post suggested a second option: Insurance. One option is to try to make sure nothing ever fails. The second option is to assume that things will fail, and have a recovery plan. This is a vaild suggestion.
The NEC these days has you drive a 6'-8' ground rod underneath the panel at the service entrance, bonded to the panel. You ALSO have to run bare copper back to the service entrance for water, and bond to that as well. In case one or the other fails, you still have a reliable path to ground. It's not simply a matter of bonding to grounds though. The panel itself needs to include a bus bar for tying all the individual grounds together, and providing a path to both both bonded ground points. So now you're basically looking at a service change, replacing the panel, meter, and mast (if applicable). It's not horribly expensive, but it's not cheap either (I used to do em for around $5k-10$k depending on the job, but that was years ago).
You don't install surge protectors to defend against a direct lightning strike --- there is no real defense against a direct lightning strike - you can make it less likely with a well-engineered lightning rod protection system.
You install surge protectors to defend against currents induced by nearby lightning in your wiring. This is protection against damage lightning can cause without actually striking your wiring, or your building. If lightning strikes a mile away from you, and hits the ground, or a tree: this lightning can still induce currents in unshielded underground and overhead power and data cables. If there is no surge protection, the induced currents may destroy sensitive electronics such as computer power supplies.
In a direct hit situation, lightning hitting a surged protected circuit can easily arc through any surge protector; human safety is paramount in the design of surge protection and electrical systems, anyways, so there are always compromises anyways, that is, surge protectors still share a common ground with everything else, and a direct hit clamped to ground can effect everything else tied to that ground --- Remember, with resistors in parallel, the amount of current is proportional to the resistance - the amount of voltage passing through the higher resistance path is not zero. Even if 99.9% of the lightning strike is clamped to ground, the 0.1% can still be 10000 volts.
No commercially available surge protector apparatus able to be fitted to a home electrical system and other utility lines entering a building with a price that is remotely affordable to the average homeowner is capable of providing remotely robust protection against a direct strike.