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#81
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The power strip and circuit breaker (or fuse) will not
interact with the power wedge. In fact, any power strip that does not have the 15 amp circuit breaker should be removed from premises as a threat to human safety. Power strip surge protector are cheap power strips with a few $0.10 parts added. The active component (MOV) remains totally inert until 120 VAC exceeds something like 300 volts. Are you seeing 300+ volts on you AC main? If not, all power strips remain inert. Meanwhile, spend tens of dollars to convert a cheap power strip into a surge protector using $0.10 parts. Better is to save money; use the cheap power strip. The power strip will provide up to 15 amps to the power wedge (or anything else). Circuit breaker protects humans from making stupid (and therefore dangerous) mistakes. To the power wedge, cheap power strip looks like power is coming directly from the wall receptacle. Agent_C wrote: Joe Sensor wrote: What exactly is wrong with a "cheap power strip"? I just want a passive switch; nothing more. I'm uncertain how the fuse and surge protection circuitry in a 'cheap power strip', or even an expensive one, would interact with the PowerWedge. A_C |
#82
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APC makes that external surge protector stipulation in a
list of exceptions. They make a warranty claim. Then include numerous 'fine print' exceptions so that a claim need not be honored. Chains of protectors adversely affect protection only because those protectors add even more wire to earth ground. No short connection to earth ground means no effective protection from the typically destructive transient. All being irrelevant to Agent_C's original post. Since a power strip (with or without surge protector) does nothing (remains inert) when voltage is well below 300 volts, then either power strip will work just like a power switch. Steve Urbach wrote: Many $9.oo strips claim some surge protection :^) Note APC protection plan states that it is void if you use external surge protectors on either the line or load as they claim that it is possible for them to interfere with each other resulting in poorer protection than either one could supply. Make sence if neither sees the full surge to initiate full clamping. |
#83
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#84
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Mike Rivers wrote: If you want to use an outlet strip, take it apart (which might require a drill or file on an outlet strip that's too cheap to be held together with screws) and clip out the MOV. It's a round thing with two leads, about the diameter of a nickel. Is it normal for US socket strips to contain MOVs ? Over here it isn't. You have to pay more for that type. Btw - just bought 2 UK 4 way strips at the local supermarket for a total of £1.75 - USD ~ 3.20. Graham |
#85
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"Pooh Bear" wrote
in message Mike Rivers wrote: If you want to use an outlet strip, take it apart (which might require a drill or file on an outlet strip that's too cheap to be held together with screws) and clip out the MOV. It's a round thing with two leads, about the diameter of a nickel. Is it normal for US socket strips to contain MOVs ? No. It is more common than it was, but its usually part of a scheme to extract a higher price from the consumer. Over here it isn't. You have to pay more for that type. Ditto. Btw - just bought 2 UK 4 way strips at the local supermarket for a total of £1.75 - USD ~ 3.20. I think Home Depot still sells 2-packs of 6-way outlet strips for about 5.00 USD. |
#86
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#87
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The normal MOV failure mode is not to open, fail shorted, or
vaporize. Catastrophic failure occurs when the MOV is installed as not intended by its manufacturer. A condition known as catastrophic failure due to a grossly undersized protector. Manufacturer provides life expectancy data sheets. MOVs degrade according to number and strength of transient current. However, when selling ineffective MOV protectors to a naive public, some companies undersized them. Then when a grossly undersized protector fails (and when protection inside the appliance actually protects the appliance), then the human says, "The protector sacrificed itself to save my computer." Effective protectors degrade. Grossly undersized protectors are undersized to be sold at excessive profits; so that a human will recommend it and buy more. Take a $3 power strip from Home Depot or Wall Mart. Install some $0.10 components. Sell the modified $3 power strip for $15 or $50 as a surge protector. A naive public will suffer catastrophic protector failure - a completely useless protector - then buy more and recommend the overpriced and undersized device to friends. Protectors might be placed either on the input or output of the conditioner. On the input, a shunt mode protector would simply provide a destructive transient with more wires into or around the conditioner. If the conditioner is working as intended, then a power strip protector connected to conditioner output would do nothing. The 120 volt power strip protector should ignore everything until voltages exceed the let-through voltage (about 300 volts). "Should" because power conditioners may not stop or eliminate those typically destructive 300+ volt transients. If the power strip is connected to a typical computer grade UPS, well, those UPSes output excessive voltage spikes when in battery backup mode. For example, this 120 volt UPS outputs two 200 volt square waves with up to a 270 volt spike between those square waves. Spikes that do not harm computers. But spikes may degrade a power strip protector or cause conditioner component failure. (Note the word degrade; not MOVs that short, open, or vaporize.) Protectors are not intended for protection from repetitive spikes as demonstrated by MOV manufacturer's chart described in 1st paragraph. Is this UPS output destructive? Yes to some small electric motors and power strip protectors. But internal computer protection would make that 200+ volt spike completely irrelevant. It's 'dirty' electrical output during battery backup mode is why power strip protectors should not be placed on UPS outputs. Last few pictures demonstrates how to remove MOVs from a power strip. Note the caption. MOVs are removed and the 'OK' light still says the power strip is OK: http://www.zerosurge.com/HTML/movs.html Mike Rivers wrote: I suspect that one reason why they might want you to hang a surge suppressor on it is because when they're suppressing, they shunt current that might otherwise be drawn by the connected equipment when it gets more than its rated working voltage. This would put an excessive load on the UPS/Conditioner. Also, although the general failure mode of a MOV surge supressor is open (giving no protection once it's failed) they've been known to fail in the shorted (or more correctly, low resistance) state, which would put undue load on the source. I don't think it has to do with chaining anything, nor do I see a problem with an external circuit breaker in line with the load. If you want to use an outlet strip, take it apart (which might require a drill or file on an outlet strip that's too cheap to be held together with screws) and clip out the MOV. It's a round thing with two leads, about the diameter of a nickel. |
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