installing new UPS for my office and needs electrical work...

[hecktic]

thanks for all the information and clarification. I guess ill just focus as much funds as possible on the bigger expenses like the whole house protector and as minimal as possible on a good power strip and/or UPS. The 2 UPS units we had just simply failed while the APC held up to the task. Ironically the APC was older and more worn out than the CyberPower and Tripplelite.

Anyways Im going to start searching for a whole house protector. How many AMPS should it cover to be worthy of a server/data room?

[hecktic]

Also I guess a whole house protector would have saved those 2 UPS/battary backups lol.. too bad we didnt think of this earlier...

[westom]

Anyways Im going to start searching for a whole house protector. How many AMPS should it cover to be worthy of a server/data room?

Protectors must earth direct lightning strikes that are typically 20,000 amps. So a minimally sized protector starts at 50,000 amps. That is for residential protection where power is shared by other homes. And when incoming power is limited to 200 amp service.

Protector life expectancy is ballpark measured by its current rating. Increasing a protector to 100,000 amps would exponentially increase the protector life expectancy.

A protector is also selected based upon service. For example home have single phase, split phase, or two phase electric (depending on the viewpoint of the observer). Commercial facilities may have three phase service. A 'whole house' protector is also selected by phase.

A 'whole house' protector is only secondary protection. Primary protection is provided by the utility. A picture of what should be inspected so that the primary protection system is also functional:
http://www.tvtower.com/fpl.html

Quality of single point earth ground mostly determines how a protector works during one surge. A protector's 'amps' mostly determines its life expectancy over many surges.

[hecktic]

Protectors must earth direct lightning strikes that are typically 20,000 amps. So a minimally sized protector starts at 50,000 amps. That is for residential protection where power is shared by other homes. And when incoming power is limited to 200 amp service.

Protector life expectancy is ballpark measured by its current rating. Increasing a protector to 100,000 amps would exponentially increase the protector life expectancy.

Alright so at least 50,000 amps but 100,000 amps would be better... I will look for the highest I can get at the best price. Maybe 150,000 to 200,000 seeing as the utility company we have is the same for the rest of the block and the whole block went down for a good couple of hours so I would probably guess the primary earth protections at the pole are of bad quality or need to be updated. My guess is they may have done this now after that whole incident last week when everything on the block was down. But I have no control over the utility company.

A protector is also selected based upon service. For example home have single phase, split phase, or two phase electric (depending on the viewpoint of the observer). Commercial facilities may have three phase service. A 'whole house' protector is also selected by phase.

Ah I see, but if I may ask, what is the difference among the phases or how do they work in respect to a commercial setting like the server/data room?

And pricing I am guessing goes higher with additional phases ?

(oh and I also gotta get a whole house protector for my apartment along with a dedicated 20amp line for my new Air Conditioner unit.... its a 14,000 btu, approx 1500watt unit)

A 'whole house' protector is only secondary protection. Primary protection is provided by the utility. A picture of what should be inspected so that the primary protection system is also functional:
http://www.tvtower.com/fpl.html

Quality of single point earth ground mostly determines how a protector works during one surge. A protector's 'amps' mostly determines its life expectancy over many surges.

yeah PG&E, our electric provider does a bad job in my area. I might have to call them up and ask them about the condition of the primary protection they have setup at the poles outside.

p.s. I appreciate your continued help and patience with me throughout this thread. I know these are probably very very basic questions and you probably dont get them a lot. But if there is anything I can do to thank you for your help, please just tell me. I am guessing you work in the electrical industry.

[westom]

... seeing as the utility company we have is the same for the rest of the block and the whole block went down for a good couple of hours so I would probably guess the primary earth protections at the pole are of bad quality or need to be updated. ...
Ah I see, but if I may ask, what is the difference among the phases or how do they work in respect to a commercial setting like the server/data room?

When power goes out, linemen typically don't look for reasons why. Their concern is to restore power ASAP. Grounds are generally (too often) handled as an afterthought. This was especially true of First Energy companies. The company that created that Aug 2003 blackout from Indiana, Michigan, Ontario, to NYC by simply violating basic procedures most everywhere. And that operated a nuclear reactor with a known potential Three Mile Island problem for many months; then discovered a hole in its containment dome.

Phases: imagine a piston that goes up and down to rotate a shaft. Now imagine three pistons located every 120 degrees around the shaft so that one piston at any time is pushing the shaft. Obviously power to rotate the shaft is more uniform when three pistons share the work. That is three phase power.

Single phase power is simply one piston pushing and pulling on the shaft to rotate it.

Electricity from generators is delivered three phase - on three wires. Peak power pulse from any one phase at any time. A three phase generator is more efficient when driving three phase motors; each phase takes turns rotating the shaft.

Homes do not need all three phases due to no big motors. So one third of homes are powered by one phase, another third by the second phase, etc. Electricity delivered to your home is a power pulse 60 times every second - one pulse every 16.6 milliseconds. But your power pulse may be 5.5 milliseconds before other houses. And their power pulse may arrive 5.5 msec before the third group.

Meanwhile, commercial buildings get pulses every 5.5 msec on three wires so that big machines can operate more efficiently. Some lights in that building are powered by the A phase. Others by the B phase. A third group by the C phase. IOW each part of the building powered just like above groups of homes are powered.

Sometimes large equipment in a data center requires three phase. Most only connects single phase.

[little_scrapper]

Would plugging a surge power strip into a UPS or even a UPS into a power strip be bad?

[westom]

Would plugging a surge power strip into a UPS or even a UPS into a power strip be bad?

Why waste money on a device that does not claim to do effective protection?

Output from this 120 volt UPS in battery backup mode is 200 volt square waves with a spike of up to 270 volts between those square waves. Power so 'dirty' as to potentially harm power strip protectors and small electric motors. And ideal power for all electronics. Because electronics have long been required to be so robust.

What are you trying to accomplish? All electronics contain superior surge protection - as the 'dirty' UPS electricity demonstrates. Anything that might work on an appliance's power cord is already inside. Protection so robust as to make that 'dirtiest' UPS power into ideal clean electricity.

Your concern is a transient so major as to overwhelm existing protection. Only an earthed protector - where power enters the building - can divert such energy harmlessly into earth.

The power strip is not effective - which is obvious by reading its numeric specs. The best power strip is a $4 strip with zero protector parts inside. And has the 'always necessary for human safety' 15 amp circuit breaker.

Maybe view another problem sometimes created by power strip protectors:
http://www.hanford.gov/rl/?page=556&parent=554
http://www.ddxg.net/old/surge_protectors.htm
http://www.zerosurge.com/HTML/movs.html
http://tinyurl.com/3x73ol entitled "Surge Protector Fires"
http://www3.cw56.com/news/articles/local/BO63312/
http://www.nmsu.edu/~safety/news/les...tectorfire.htm
http://www.pennsburgfireco.com/fullstory.php?58339

Why do informed homeowners earth only one 'whole house' protector? Because even power strip protectors need to be protected. Why buy a power strip that does not even claim effective protection?

[little_scrapper]

Why waste money on a device that does not claim to do effective protection?

Output from this 120 volt UPS in battery backup mode is 200 volt square waves with a spike of up to 270 volts between those square waves. Power so 'dirty' as to potentially harm power strip protectors and small electric motors. And ideal power for all electronics. Because electronics have long been required to be so robust.

What are you trying to accomplish? All electronics contain superior surge protection - as the 'dirty' UPS electricity demonstrates. Anything that might work on an appliance's power cord is already inside. Protection so robust as to make that 'dirtiest' UPS power into ideal clean electricity.

Your concern is a transient so major as to overwhelm existing protection. Only an earthed protector - where power enters the building - can divert such energy harmlessly into earth.

I was having weird issues and wondered if I had brown power issues. Without an O-scope or even a good and fast true RMS meter I couldnt tell, so I just said hell with it and bougt a Cyberpower CP1350AVRLCD. The question stemmed from me being too lazy when I got my UPS. I simply pulled the plug for the power strip and plugged it into the back of my UPS.

The Cyberpower was "reviewed" (takes salt grain) to be one of the LESS crappy simulated sine wave ones (stepping sine wave). I never really considered the output effects on my power strip until after reading your guys thread here. Thus the question.

With my knowledge of MOV's and how they work, and what you say about the output of a UPS on battery(again i personally have never scopped one out), I could easily surmize that prolonged crappey battery output from the UPS could cause the MOV's in the surge strip to overheat, fail, and/or cause a fire. That is assuming that the peaks are suffecient, prolonged, and frequent enough. I guess I should just go ahead and pull out the strip until I can scope out the battery output of my UPS and see what the ACTUAL output looks like.

On a side note I really need to invest in a good meter that reads TRUE RMS.

[westom]

I was having weird issues and wondered if I had brown power issues.

Brownouts are voltages that drop well below 120 VAC. Surges are events that exceed maybe 330 volts. And exist only for microseconds. No meter is going to record a surge.

Best tool for finding brownouts is an incandescent light bulb. All electronics have ideal voltage even when that bulb is at 50% intensity. If having brownouts (low voltages), the bulb will make that problem obvious. If any major appliance powers cycles and causes the bulb to dim or brighten, then fix defective household wiring. In rare cases, that intensity change may report a serious human safety issue.

The strip is not at risk when the UPS is not in battery backup mode. The UPS connects directly to AC mains via a relay. That means power is cleanest. An also why protection is mostly mythical. Problems occurs when the UPS provides temporary battery power.

MOVs that "overheat, fail, and/or cause a fire" must never exist in a building. MOV normal failure is to degrade - a 10% voltage change. To promote sales, many power strips are undersized. A surge too small to harm any electronics causes the protector circuit to fail and disconnect. That gets the naive to assume, "My protector sacrificed itself to save my computer." Nonsense.

MOVs are effective when connecting a massive surge harmlessly to earth. And the protector must remain functional. Therefore facilities that cannot suffer damage earth 'whole house' protectors. And not use power strip protectors.

A minimal 'whole house' protector for residences is 50,000 amps. So that it can even earth the typical 20,000 amp direct lightning strike. And so that MOVs do not "overheat, fail, and/or cause a fire" - which would violate manufacturer absolute maximum parameters. Oh. And would also threaten human life.

[little_scrapper]

Ok so i understand the resons for grounding the power/telephone poles, and I understand the 'whole house' protectors. Are these also called lightening arrestor systems or is that something else?

Should one have grounded lightening rods on thier house or is this just "encourageing a strike" rather than routing errant lightening into the ground? Which is worse?

Sorry, im not trying to hijack the thread.

EDIT: ok I did a bunch of reading and according to the people that sell lightening rod systems, hehe, I definately SHOULD have them. Something like this.
http://lightningrodstuff.com/index_files/page0004.htm

[hecktic]

When power goes out, linemen typically don't look for reasons why. Their concern is to restore power ASAP. Grounds are generally (too often) handled as an afterthought. This was especially true of First Energy companies. The company that created that Aug 2003 blackout from Indiana, Michigan, Ontario, to NYC by simply violating basic procedures most everywhere. And that operated a nuclear reactor with a known potential Three Mile Island problem for many months; then discovered a hole in its containment dome.

Phases: imagine a piston that goes up and down to rotate a shaft. Now imagine three pistons located every 120 degrees around the shaft so that one piston at any time is pushing the shaft. Obviously power to rotate the shaft is more uniform when three pistons share the work. That is three phase power.

Single phase power is simply one piston pushing and pulling on the shaft to rotate it.

Electricity from generators is delivered three phase - on three wires. Peak power pulse from any one phase at any time. A three phase generator is more efficient when driving three phase motors; each phase takes turns rotating the shaft.

Homes do not need all three phases due to no big motors. So one third of homes are powered by one phase, another third by the second phase, etc. Electricity delivered to your home is a power pulse 60 times every second - one pulse every 16.6 milliseconds. But your power pulse may be 5.5 milliseconds before other houses. And their power pulse may arrive 5.5 msec before the third group.

Meanwhile, commercial buildings get pulses every 5.5 msec on three wires so that big machines can operate more efficiently. Some lights in that building are powered by the A phase. Others by the B phase. A third group by the C phase. IOW each part of the building powered just like above groups of homes are powered.

Sometimes large equipment in a data center requires three phase. Most only connects single phase.

Alright well its not that big of a "data center" although the power to the building and the rest of the block is considered for commercial purposes so Ill see if I can find a good three phase whole house protector. Going to try for 150,000amp protector if possible.

Also I need to get one for my apartment since I got that new AC and it requires a dedicated line (15amp but Ill get a 20amp to be safe) and I also have a new home theator system which I want to put on its own dedicated line also (20amp should be enough I think but Im not sure how I would plug everything in since the physical connector wont match the 20amp outlet plug) I think a 50,000amp whole house protector would be enough for all of this but since this is a large apartment complex building next to four others, I think Im going to try and get a 100,000amp whole house protector (will try and get a double phase if its reasonable for the price)

Do you have any idea of what the pricing SHOULD be?

Sorry, im not trying to hijack the thread.

Thats fine. The MOV discussion is relevant to my project also. Before knowing this information I was not planning on putting primary earth protection via the copper rods around the data room (esp. near the breaker box and whole house protector), but now I am going to.

[westom]

Ok so i understand the resons for grounding the power/telephone poles, and I understand the 'whole house' protectors. Are these also called lightening arrestor systems or is that something else?

Should one have grounded lightening rods on thier house or is this just "encourageing a strike" rather than routing errant lightening into the ground?

Lightning hunts for earth no matter what anyone does. A lightning strike down the street is a direct lightning strike to all household appliances. So we earth all incoming wires directly (cable TV, satellite dish) or via a 'whole house' protector (telephone, AC electric). Other sources of these transient include high voltage wires falling on local distribution, transients created by utility switching, stray cars, etc.

Lightning strike to a building is diverted (connected to earth) via lightning rods. That strike will occur with or without lightning rods. You simply choose what the path to earth will be. How much protection do you need? Neighborhood history for the past ten years is one indication for how much (or what) you might need.

Best price for a 'whole house' protector is in Lowes and Home Depot. Larger protectors for commercial installations may be $200. Best is to consult the electrician for what he usually installs. Installation in an apartment building (should) require an electrician. Pricing also available at electric supply houses. Some examples if they have not changed the link again:
http://www.eaton.com/ecm/idcplg?IdcS...ILE&dID=287147

[little_scrapper]

Let me ask you this. The wires/cables; should they be solid or stranded? I figured they should be solid, but everything I see listed online has braided copper or aluminum for the wires.

[westom]

Let me ask you this. The wires/cables; should they be solid or stranded? I figured they should be solid, but everything I see listed online has braided copper or aluminum for the wires.

To be a better surge conductor, a ground wire is best flat. But the ground wire must also remain intact over decades of weather. Therefore ground wires are typically solid round copper so that corrosion and other damage does not subvert that connection.

[little_scrapper]

Why flat? Does the EMF produced by AC component of the strike cause the skin effect. If thats the case then I can understand why everyone is pimping the braided conductors (more surface area). But it would seem that once the dielectric breakdown of the air is completed and the current starts to flow into the ground, its a completely DC current, and thus a solid copper wire would be best. It must be the delta C then. The drop in current causing the change in EMF.

Realistically we didnt cover lightening all that well in Physics I or II. Hehe. My physics book has a whole 1.5 pages on lightening and 1 paragraph on lightening rods. Lightening: Consisting of charges built up in 50m steppers and 'bang'... lightening. Rods: you need a sharp point to ionize the air around the tip. phht how phlimsey is that.

[westom]

Why flat? Does the EMF produced by AC component of the strike cause the skin effect. If thats the case then I can understand why everyone is pimping the braided conductors (more surface area).

Science says blunt rods are significantly better than sharp pointed rods. But urban myths live on long after the science is discovered. Unfortunately most of us are only educated by advertising - much less knowledge comes from science.

Surges are not DC. Surges are radio frequency transients. Protection is always about impedance - not about resistance.

It was an old joke in engineering school. The DC transient. No such thing exists. Switched DC is a sum of sine waves (Fourier Series) - is not DC current. Lightning is about sine waves at many radio frequencies - is not DC current.

Braided wire does not have appreciable lower impedance compared to solid wire. To significantly lower impedance, each wire in the braid would be separated. Braided wire breaks down, corrodes, or fails faster. Any advantage in lower impedance is irrelevant compared to environmental damage.

Impedance is why a wire with sharp bends compromises protection. Impedance is why wire length (not wire thickness) is the relevant parameter. Why an effective protector must be located so close to single point ground. Why better protection means electronics separated from the protector. And why even splices compromise protection.

The fundamental concept. Lightning is conducted to earth via wooden church steeples. But wood is not a superior conductor. 20,000 amp lightning strike conducted by wood results in a high voltage. 20,000 amps times a high voltage is high energy. Church steeple destroyed.

Franklin simply earthed lightning rods. Rods do no protection. Protection is the earth ground connection. 20,000 amps through a conductive wire to earth is low voltage. 20,000 amps times a low voltage is low energy. No damage. Surge is harmlessly absorbed in earth.

All effective protection does that. Franklin solved lightning to earth destructively via a building. 'Whole house' protector solves lightning to earth destructively via appliances.

Essential to appliance protection is a low impedance (ie 'less than 10 foot') connection to single point earth ground. Better earthing means most energy dissipates outside. Less energy to overwhelm protection already inside every appliance. A protector - or a lightning rod - is only as effective as its earth ground. A lowest impedance (not resistance) connection.

[hecktic]

Are Line conditioners needed for a data room? home?

[westom]

Are Line conditioners needed for a data room? home?

Many if not most line conditioners are nothing more than power strip protectors inside a fancy box, renamed, and sold for $hundreds.

Any line conditioning that that expensive box does is already inside electronics power supplies.

For example, what does a power supply do? First AC power passes through a serious line filter. Then converted to high voltage DC (exceeding 300 volts). Then filtered again. Every electronic power supply has now done more than any line conditioner might do. And that is only the supply's front end.

Then the supply converts high voltage DC to high voltage radio frequencies. Any 'dirty' electricity is now made much 'dirtier'. Then filtered again. Passes through galvanic isolation while high voltage is converted to high current. Then the low voltage radio frequency is converted to DC. And filtered again.

Show me a line conditioner that does any such conditioning? Reasons why DC voltages inside all electronics are so clean. Converted to much higher voltages. It is made even dirtier. Filtered so many times after each conversion. Converted from AC to DC to AC and then to DC again. Where does any line condition even begin to do any of this?

It is called a line conditioner. The only reason why so many recommend it. That thing called a power supply (that does massive line conditioning)? It does not sound like line conditioning. Therefore it must not do all those things listed above.

Too many will promote that line conditioner because their only electrical knowledge is a 'feeling'. It sounds like it must do something because a power strip protector is now called a *line conditioner*. Scams are so easy to promote when so many make recommendations based only on its name. Never once learn any numbers.

View the spec numbers for that line conditioner. Many have numbers that are identical to a $25 power strip protector. A majority will ignore numbers. Only hear the name. Then *know* it must do more.

Line conditioners typically do almost nothing. Job of a power supply - to do massive line conditioning. Rather amazing how much a power supply does with so few parts. Some appliance power supplies do even more for very little more money. Tens or 100 times less than what so many pay for line conditioners.

[hecktic]

Many if not most line conditioners are nothing more than power strip protectors inside a fancy box, renamed, and sold for $hundreds.

Any line conditioning that that expensive box does is already inside electronics power supplies.

For example, what does a power supply do? First AC power passes through a serious line filter. Then converted to high voltage DC (exceeding 300 volts). Then filtered again. Every electronic power supply has now done more than any line conditioner might do. And that is only the supply's front end.

Then the supply converts high voltage DC to high voltage radio frequencies. Any 'dirty' electricity is now made much 'dirtier'. Then filtered again. Passes through galvanic isolation while high voltage is converted to high current. Then the low voltage radio frequency is converted to DC. And filtered again.

Show me a line conditioner that does any such conditioning? Reasons why DC voltages inside all electronics are so clean. Converted to much higher voltages. It is made even dirtier. Filtered so many times after each conversion. Converted from AC to DC to AC and then to DC again. Where does any line condition even begin to do any of this?

It is called a line conditioner. The only reason why so many recommend it. That thing called a power supply (that does massive line conditioning)? It does not sound like line conditioning. Therefore it must not do all those things listed above.

Too many will promote that line conditioner because their only electrical knowledge is a 'feeling'. It sounds like it must do something because a power strip protector is now called a *line conditioner*. Scams are so easy to promote when so many make recommendations based only on its name. Never once learn any numbers.

View the spec numbers for that line conditioner. Many have numbers that are identical to a $25 power strip protector. A majority will ignore numbers. Only hear the name. Then *know* it must do more.

Line conditioners typically do almost nothing. Job of a power supply - to do massive line conditioning. Rather amazing how much a power supply does with so few parts. Some appliance power supplies do even more for very little more money. Tens or 100 times less than what so many pay for line conditioners.

No I agree completely, infact most new server power supply units and even desktop/workstation PSUs do exactly as you just said. It makes complete sense.

But what about for an appliance that doesn't have a Power Supply like a computer. Like maybe a High Def. TV? Any idea if these TVs would benefit from a Line conditioner? If so, what spec should the line conditioner be?

like this:
http://www.us-appliance.com/pw101.html

[westom]

But what about for an appliance that doesn't have a Power Supply like a computer. Like maybe a High Def. TV? Any idea if these TVs would benefit from a Line conditioner? If so, what spec should the line conditioner be?

Power supplies are inside any electronics that must have stable and regulated voltages. For example, all computers use 3.3, 5, and 12 volts DC with regulation that is much better than 5%, low ripple voltages, etc. 120 volts AC can vary 20% and even drop out completely for milliseconds. And those 3.3 etc voltages must remain perfectly stable and ideal. Too many functions to list are what a power supply does for all electronics.

That line conditioner is only an expensive power strip protector. Those specs are vague even about filtering - that is already accomplished in every power supply.

Numerous electrical anomalies exist including brownouts, blackouts, surges, noise, power factor, harmonics, etc. Each is solved in a different location. This line conditioner claims surge protection and does not have the always required short connection to earth? Nonsense. It may do some trivial noise filtering (64 dB) but really does not say what gets filtered. And claims to solve nothing else. In short, anything it might do must already be performed by power supplies that exist inside all electronics.

Why must a computer power supply cost at least $60 retail? Because the supply must solve so many problems and regulate voltages. That PW101 for $125 does virtually nothing or does less (64dB) than what every power supply must already do - for over double the price. The line conditioner is only a high profit $25 power strip protector hyped so that it can sell for $125.

[hecktic]

Power supplies are inside any electronics that must have stable and regulated voltages. For example, all computers use 3.3, 5, and 12 volts DC with regulation that is much better than 5%, low ripple voltages, etc. 120 volts AC can vary 20% and even drop out completely for milliseconds. And those 3.3 etc voltages must remain perfectly stable and ideal. Too many functions to list are what a power supply does for all electronics.

That line conditioner is only an expensive power strip protector. Those specs are vague even about filtering - that is already accomplished in every power supply.

Numerous electrical anomalies exist including brownouts, blackouts, surges, noise, power factor, harmonics, etc. Each is solved in a different location. This line conditioner claims surge protection and does not have the always required short connection to earth? Nonsense. It may do some trivial noise filtering (64 dB) but really does not say what gets filtered. And claims to solve nothing else. In short, anything it might do must already be performed by power supplies that exist inside all electronics.

Why must a computer power supply cost at least $60 retail? Because the supply must solve so many problems and regulate voltages. That PW101 for $125 does virtually nothing or does less (64dB) than what every power supply must already do - for over double the price. The line conditioner is only a high profit $25 power strip protector hyped so that it can sell for $125.

Alright, but how important is noise filtering for sensitive electronics like the high def. TV? Numerous claims say it helps picture quality, etc... but is that really true?

[westom]

Numerous claims say it helps picture quality, etc... but is that really true?

Where are the numbers? Claims made without numbers are classic junk science.

Again, view the previous power supply description. After filtering all noise, then converting AC power to higher voltage DC. Then it converts that power into massive, noisy power - high voltage radio frequency electricity. Matters little what arrives on the AC power cord. To make ultra pure DC, a supply still makes that electricity much noisier. And but again filters out all noise to create purest DC. Any noise on AC is tiny compared to noise intentionally created inside a power supply.

What is a greater noise source? If the incoming cable is not properly earthed where it enters the building.

Others have no idea how a power supply works. Have no idea that electricity is converted to higher voltage DC, then made massively noisier etc. Have no idea of the many filters already inside all electronic supplies. Instead, a majority see the words "line conditioner" or "noise filter". Then ‘feel’ (wildly speculate) those add-ons must be superior. Are routinely scammed because subjective recommendations are respected. A recommendation without numbers is classic junk science. Anything that noise filter might barely do is done repeatedly and better inside every power supply.

Where are their numbers for improved picture quality? Never exists. Myths – and Saddam’s WMDs are a perfect and duplicate example – are routinely promoted and believed when the myth is a first thing told and when numbers are not always demanded.

If noise is harming picture quality, then high voltage radio frequencies intentionally generated inside all power supplies are more likely the source for that noise.

[rogard]

westom...thank you for your detailed replys not only are they very helpful but they are also great reference for the future.

[little_scrapper]

I am still scratching my head over your blunt rod vs sharp rod statement. My understanding is that a sharper point with its tighter radius is better able to ionize the air immediately around it, and thus make that area 'more' attractive for the lightening. Yes the sharp tip would readily melt into a blunt tip once struck ... But is that not correct in that the tighter radius of a sharper tip creates a more intense field that is able to more readily ionize the surrounding air?

[westom]

I am still scratching my head over your blunt rod vs sharp rod statement. My understanding is that a sharper point with its tighter radius is better able to ionize the air immediately around it,

From Dr Charles Moore's Nov 1975 paper and from others:
"... our results indicate that the sharpened rod usually acted to protect itself by emitting ions whenever the electric field exceeded the breakdown threshold. The blunt rod, on the other hand, emitted ions with great difficulty...the fields around the blunt rod often large values that when breakdown did occur at the blunt rod a positive streamer could propagate for appreciable distances away from the blunt rod."

"Field trials in the summers of 1994-98 at Langmuir Labs have provided electric current measurements flowing from various shaped lightning rods. These were correlated to changes in electric fields caused by lightning discharges. Results of this work confirm earlier theoretical models about sharp vs blunt rod behavior. (3) Sharp rods are poorer receptors for lightning than blunt rods."

Again the point. In many fields where knowledge comes mostly from hearsay: what is popularly believed (without numbers) too often does not agree with reality.