linda@wpg.com (Linda Guidry) (03/22/89)
One of my non-net neighbors has had some *serious* surge problems
lately and has asked me to post a query to the net requesting advice.
Given the fact that there are a jillion different surge protectors
on the market these days, she'd really appreciate some suggestions
from electrical engineers and/or knowledgeable consumers concerning
the names of the better brands.
Also, what features should my friend be looking for to protect
computers and laser printers?
--
Linda Guidry, WP Group, New Orleans (504) 443-5000
{uunet,killer}!wpg!lindawjm@mruxb.UUCP (mitchell) (03/23/89)
In article <1099@wpg.com>, linda@wpg.com (Linda Guidry) writes: > > One of my non-net neighbors has had some *serious* surge problems > lately and has asked me to post a query to the net requesting advice. > > Given the fact that there are a jillion different surge protectors > on the market these days, she'd really appreciate some suggestions > from electrical engineers and/or knowledgeable consumers concerning > the names of the better brands. > > Also, what features should my friend be looking for to protect > computers and laser printers? > -- > Linda Guidry, WP Group, New Orleans (504) 443-5000 > {uunet,killer}!wpg!linda When looking for a surge protector, consider the following. To start, the unit should be listed for safety by UL or another recognized electrical testing laboratory (such as CSA in Canada). Listing only determines that the samples submitted for testing met the applicable specification of the testing laboratory and were free from the safety/fire hazards covered by that standard. It does not cover performance as a surge protector. Therefore, you should also look for a unit that complies with IEEE (the Institute of Electrical and Electronic Engineers) Standard 587. IEEE 587A provides a minimum level of surge protection, while IEEE 587B provides a higher level of protection and would be recommended in high surge areas. Also, you want a unit that provides surge protection in 3 places 1 - between the hot and neutral wires 2 - between the hot and ground wires 3 - between the neutral and ground wires Some cheap units only protect between the hot and neutral wires, leaving you vulnerable to surges coming in using the ground for one conductor. Desirable features: Indicator lights to let the user know that the surge protection is working - some types of surge protection devices will self-destruct to protect your computer, and have to be replaced after a major surge. Also, if you have a modem, you should provide surge protection on the telephone line as well as the power line. A basic surge protector will protect against spikes and surges, but will not protect your computer against RF noise that comes in on the power line. I would recommend getting a unit that also provides RFI/EMI filtering as well as surge protection. Unfortunately, in surge protectors, like everything else, you get what you pay for - a good surge protector is going to cost around $50 or so, more if it has other conveniece features like additional outlets, switches for periphials, phone line protection, etc. Even the best surge protector/EMI filter won't protect your computer against blackouts and power dips. To protect against that you'll need (in addition to the surge protector/EMI filter) an uninterruptable power supply or UPS. UPSs aren't cheap - a unit that will run an IBM AT or similar model for 5-10 minutes during a power failure, giving you time to save your work and do a controlled shutdown of the system, will cost several hundred dollars. Regards, Bill Mitchell Disclaimer - these are strictly my personal opinion and are not necessarily those of my employer, this VAX, or my dog (but she finds blinking lights on electronic equipment mildly interesting when she can't beg any munchies off her owner.)
jwi@lzfme.att.com (Jim Winer @ AT&T, Middletown, NJ) (03/24/89)
In article <1099@wpg.com>, linda@wpg.com (Linda Guidry) writes: > > One of my non-net neighbors has had some *serious* surge problems... > > Given the fact that there are a jillion different surge protectors > on the market these days, she'd really appreciate some suggestions > from electrical engineers and/or knowledgeable consumers concerning > the names of the better brands. > > Also, what features should my friend be looking for to protect > computers and laser printers? Depends on what *serious* means: If you have frequent power-outs, you need a UPS (Uninteruptable Power Supply). If you only have power-outs twice a year during thunder storms, you don't. (But don't use the machine during thunder storms.) They include back-up power, voltage stabilization, spike protection, and RFI/EMI interference protection. They come in both square wave output (cheap) and sine wave output (expensive). Which you need depends on what you are plugging in -- I think (but am not sure) that a switching power supply as used in most computers will not care. Anything with an actual motor running off the power line will care. If you have frequent brown-outs, but not power-outs, you need a line stabilizer. TrippLite makes them in 600VA, 1200VA and 1800VA ratings. They automatically adjust for low or high line voltages. They include voltage stabilization, spike protection, and RFI/EMI interference protection, but not back-up power. I use the 1800VA version with my printer plugged in to the first stage filter and my computer at the 3rd stage filter. (See below.) If you have frequent power drops when the fridge or the furnace starts or another appliance starts, you need a private circuit to your computer or possibly a higher amperage service from the power company. Spikes will always accompany electric motors starting so you must have at least spike protection. If you get strange results when the vacuum cleaner is running, or when electric or radio equipment is in use, you need RFI/EMI filtering. It is available in the better spike protectors. If you think you can get away with a spike protector, be sure it includes RFI/EMI filtering. In general: It should have both common mode and transverse mode spike protection. The cheap ones have only one mode because it requires only 1/3 the parts. The good ones are protected from both wires to ground and between the wires -- 3 times the parts. The cheap ones start at $7.95. The good ones start at about $35, but price is not a guarantee. RFI (radio frequency interference) and EMI (electromagnetic interference) are filtered out by a whole bunch of little parts. Again there is common mode and transverse mode. In addition, there is multi-stage filtering where the outlets are isolated from each other -- you plug the printer into the first level filter and you plug the computer intothe third level filter. Unfortunately, the advertisers tell you the clamping time in nanoseconds and the power dissipation in joules. If that's all they tell you, don't buy it. Look for common AND transverse mode clamping and EMI/RFI filtering. A reliable brand is Tripp-Lite (no affiliation) which was an editor's choice in PC Magazine. If you want specs on these things, you will have to look in the reviews. The manufacturers don't provide them. Jim Winer ..!lzfme!jwi I believe in absolute freedom of the press. I believe that freedom of the press is the only protection we have from the abuses of power of the church, from the abuses of power of the state, from the abuses of power of the corporate body, and from the abuses of power of the press itself. Those persons who advocate censorship offend my religion.
smh@alux2.ATT.COM (S. Henning) (03/29/89)
> In article <1099@wpg.com>, linda@wpg.com (Linda Guidry) writes: > > > > One of my non-net neighbors has had some *serious* surge problems... > > > > Given the fact that there are a jillion different surge protectors > > on the market these days, she'd really appreciate some suggestions > > from electrical engineers and/or knowledgeable consumers concerning > > the names of the better brands. > > > > Also, what features should my friend be looking for to protect > > computers and laser printers? I installed a primary surge protector in my breaker box. These are available at most electrical supply houses. They provide gas tube protection at the point of entry. Gas tubes can absorb an enormous amount of energy but are not as fast as zener diodes. At the point of use another good protector is desirable. It usually has a surge absorber made from either a gas tube or a zinc oxide MOV and also an electronic surge barrier formed from inductors, capacitors and zener diodes. This 2 level surge protection is the only level that will survive a close lightning strike. My house is full of electronic goodies and before we installed the above system, we were sending things back to the manufacturer to be repaired all the time. Now we have no problems. Don't forget that surges come in the phone line and cause problems. The phone company installs primary protectors where the wires enter your home. These are designed to keep the voltage on the phone line from rising above 600 to 1000 volts depending upon the model, and the number of times that it has been zapped. I found out the hard way that this is not good enough to protect some modems. Now I use a secondary lightning protector on all lines with modems. These are available from such places as Inmac for $59. I have had two of the Inmac protectors smoked (burned up) by lightning strikes but they saved the modem in each case. If some one knows of a better protector I would be interested. I am on the end of a long telephone line that runs through a valley. Whenever a storm hits the valley, our phone rings on every strike. However, only when we get a strike in our yard do we get the protectors smoked. As to brands, stick to ones backed up by you local computer store. The world is full of inexpensive clones that are not UL rated. Avoid these. In addition to UL rating, look for the IEEE 587 rating. This pertains to the effectiveness as a surge protector while the UL rating is for fire insurance purposes. The best point of use protectors meet IEEE 587 class A & B. The gas tube protectors that fit in the breaker box only have a UL rating. Cheers, Steve Henning, AT&T Bell Labs, Reading, PA UUCP: att!alux2!smh **** Lang May Your Lum Reek ****
apranger@jarthur.Claremont.EDU (L. Alex Pranger) (03/31/89)
I also am in need of similar information, but from reading the postings I'm not really sure what exactly my needs are. I work at a Boy Scout summercamp, and I would like to use my computer. by one of two Disel generators. This system is prone to frequent "Brown Outs" the surges. I am not really worried about the Brown outs as much as I am about money (my editor is giving me problems ignor glitches) to spend. So will it be better to get a suicide fuse, then just keep replacing it, or should I get the into a battery then giving battery power to the computer. (at least this is how I think it works). Cost is an important factor, but the life of the computer is more important. Please recomend brands too. Respond by post or e-mail, Thanks in Advance: L. Alex. Pranger apranger@hmcvax.bitnet apranger@jarthur.claremont.edu apranger@jarthur.UUCP
rk@unify.UUCP (Ron Kuris) (04/03/89)
It seems to me that you are more interested in Line Regulators than
Surge Protectors. You mentioned about "brown outs"... how can a
surge protector protect against this? Either you should be looking
for an Uninterrupted Power Supply with Line Voltage Regulation or
merely a Line Regulator. They've been around for some time.
You mentioned that cost was a factor -- you may be in for a surprise.
Only the most expensive UPS units have line voltage regulation! Check
the specs before you buy.
It would also be useful to know what type of equipment you are hooking
up to the unit.
--
Ron Kuris (916) 920-9092
rk@unify.UUCP
{{ucdavis,csun,lll-crg}!csusac,pyramid,sequent}!unify!rk