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audiomuze
2009-12-24, 14:22
I'm hoping folks can shed some light on precautions they've taken/ can be taken to eliminate/ minimise the threat of damage to one's PC, network infrastructure, Squeezeboxen & other hi-fi equipment. Every time a thunderstorm is imminent I unplug the telephone line from my router and IP phone, unplug all of the abovementioned from the wall sockets and wait the storm out. The incoming mains also has lightening suppression installed for each phase. While it's obviously effective it's a pain in the butt because it always seems to coincide with listening time. What are my options? Oh, merry Christmas :-)

iPhone
2009-12-24, 14:39
I'm hoping folks can shed some light on precautions they've taken/ can be taken to eliminate/ minimise the threat of damage to one's PC, network infrastructure, Squeezeboxen & other hi-fi equipment. Every time a thunderstorm is imminent I unplug the telephone line from my router and IP phone, unplug all of the abovementioned from the wall sockets and wait the storm out. The incoming mains also has lightening suppression installed for each phase. While it's obviously effective it's a pain in the butt because it always seems to coincide with listening time. What are my options? Oh, merry Christmas :-)

It is my opinion and experience that the best thing is to eliminate a ground path for Lightening. Again my opinion on this is to use something like Richard Gary Power Company 220V Substation wired for 220. If its wired for 120, then there is a path to ground. By wiring so the transformer has 2 hots there is no path for Lightening to get to a ground via ones equipment. This also has huge advantages for ones equipment as in no line sag.

Power Strips are the worst things in the world if they have MOV in them. These devices take a few strikes and then are useless and there is no indication that the surge strip is no longer trying to protect anything.

One less expensive route then RGPC products is to use a product called Brick Wall (http://www.brickwall.com/) (warning, only order directly from the company there are scammers selling a box that looks like theirs but doesn't have the coils and components inside, just some cheap MOVs and a path to ground). These can also be placed around the house as they are outlet specific. Yes more expensive then most surge protector, but Brick Wall's are not surge protection they are Lightening protection. I have not lost a single piece of equipment protected by RGPC or Brick Wall. We use Brick Wall to protect the PCs at our cellular sites that take up to 200 strikes a storm during the summer thunderstorm season. Yes the towers have the best Lightening protection money can buy, but when you're the highest thing on top of the mountain, you're going to take strikes!

seanadams
2009-12-24, 15:39
I have spent a lot of time researching surge suppression as it is a real problem I have run into lately.

You didn't say what you're using now but one of the most effective solutions for whole-home protection is to get a "TVSS" module that is designed for your panel(s) and fits in the space of a dual-pole breaker (for example, here's one for a Square D Homeline panel: http://tinyurl.com/ydq736z ). These must be positioned only in the top-right slot to be maximally effective, so you will probably need to move all the other breakers down two spaces - usually that is not a big deal. These devices have LEDs on them which you should check every few months to make sure they're alive - if you are getting surges and they're doing their job, they will eventually expire. Also, cut their neutral pigtail as short as possible.

The only thing better than that is an large external TVSS **BUT** this will only be an improvement if you actually route the main feed THROUGH this device - and for that to work it must be rated for passthrough current equal to the main disconnect feeding it. If you are on 200A service then it's probably not practical, although I did once hang one off the side of a panel using a 60A breaker on the grounds that it would be better than nothing.

The reason wiring distances come into play is that a lightning strike is an RF signal because of the rapid rise of the voltage. Every foot of cable between your breaker panel and the TVSS results in about 150V of reduced clamping voltage. You you can still get some benefit from a "dangling" TVSS, but not as much as putting them right in the path of the surge.

If you have already put TVSS devices on your main/sub panels then you're probably already at the point of diminishing returns there as far as >500V suge events are concerned.

This still leaves brownouts and lower, longer duration overvoltages. These may not be a problem for you but they can be prevented by putting your most expensive equipment on good quality UPSes.

Finally, your phone lines (and cable TV, if it's an aerial feed) are a very likely vector for surges to enter the house but usually these only threaten the modems or data interfaces in the particular devices to which they're connected. APC makes a MOV-based device, but there is a new product from ELK which more sophisticated and supposedly better (http://www.smarthome.com/1298/Elk-ELK-952-In-Line-Telephone-Surge-Protector/p.aspx). That product is made for alarm panels - I don't know if it is OK for modem/fax/DSL. It is very important with these devices that they have a good ground connection - but also that the ground connection is close to the device being protected. You can put one in your phone box but it would be best to put them individually at your alarm panel, DVR, etc and connect them to the same nearby ground.

seanadams
2009-12-24, 15:49
It is my opinion and experience that the best thing is to eliminate a ground path for Lightening.

I don't think that's possible in practice, unless you live on a boat or are prepared to grossly violate the electrical code by removing ALL earth ground connections. Otherwise the "equipment grounding conductors" become the shortest path to ground for a common-mode surge, and you're going to cause much more damage because it's finding its way through your electronics to a chassis ground, rather than the neutral leg.

toby10
2009-12-25, 05:53
Good surge protection is like good security, best provided in layers.

At my main box:
- 8' ground spike
- Square D fast trip breakers
http://www.squared.com/us/products/circuit_breakers.nsf/unid/D6F176AE4B7FD96C85256C8600760A01/$file/QOcircuitbreakerFrameset.htm

At my AV rack:
- Furman PS-8R II (series mode surge protection, line filtering, sequenced switched outlets)
http://www.furmansound.com/product.php?div=01&id=PS-8R_II

At my flat panels:
- Furman AC-215 II (series mode surge protection, line filtering)
http://www.furmansound.com/product.php?div=01&id=AC-215_PRO

At my server:
- Brick Wall PW8R15 (series mode surge protection,)
http://brickwall.thomasnet.com/item/standard-surge-protectors/eight-outlet-surge-protectors/pw8r15?&forward=1

As suggested by others, stay away from anything with MOV technology. This is the same technology used in $3 "surge protectors" sold at drug stores. You want tested series mode fast clamping surge protectors.

seanadams
2009-12-25, 08:47
As suggested by others, stay away from anything with MOV technology. This is the same technology used in $3 "surge protectors" sold at drug stores. You want tested series mode fast clamping surge protectors.

Practically everything uses MOVs, including the products you just linked! See their marketing papers:

http://www.furmansound.com/pdf/pdfdata/furman_mov_facts.pdf
http://www.furmansound.com/pdf/pdfdata/FurmanSMPPlusWhitePaper.pdf

Yes, they _additionally_ include a series element to dissipate the surge, but so does any TVSS installation to some degree (the wire feeding it is an inductor, if nothing else).

Just because they use the same shunting principle doesn't mean all TVSS devices are equivalent to a $3 surge protector. Series circuitry can protect you from sustained overvoltages, but for lightning you need a high speed clamping element and MOVs are what the whole world uses.

[edit: Brick Wall uses a different clamping element but I'm skeptical as to how well it would handle lightning. Their test results highlight the lower clamping voltage in an idealized low speed event, which says nothing of how it responds to higher slew rate impulse. Also, you're not going to find something like that for the service entrance or subpanel.]

SamS
2009-12-27, 10:20
Sean is right on the money here.

I had an electrician install this TVSS at my breaker panel. It was only $60, and I think it will ultimately do a better job at the breaker than those $2K jobbers that go in your rack.

http://kirkwoodelectric.net/images/CHSPMAX.jpg