lightning protection both ends of cable

[HeadsUp 0]

i have a CAT5 cable which runs over the top of a steel roofed building

 

i know its not ideal to run cable that way but its due to a dispute over access between occupants in rented factory units

 

the cat5 is inside glued PVC conduit and laid over the roof , with blobs of silicon every 10 feet to hold it down during windy days

 

 

My question is . can i use two lightning surge protectors on the same cable , one at the camera and one at the DVR ?

 

i want to protect both items from lightning strike even though the PVC conduit would be a good insulator , the camera body is screwed to aluminum window frames which are screwed to structural steel and roof cladding

 

thoughts ?

 

thankyou.

[tomcctv 187]

the camera body is screwed to aluminum window frames which are screwed to structural steel and roof cladding

 

 

hi Headsup. lightning protection will not work in your case.

[HeadsUp 0]

the camera body is screwed to aluminum window frames which are screwed to structural steel and roof cladding

 

 

hi Headsup. lightning protection will not work in your case.

 

 

sorry i should have mentioned that the camera CCD board is screwed to a plastic plate inside the camera body and has about 20 mm air gap away from the aluminum body . does that change things ?

 

i know lightning generally takes the shortest path with least resistance , but it can also blow the guts out of anything attached to its path too

 

the surge protectors would be earthed

 

the DVR has lightning protection on its mains power supply , and also on the mains power input for the camera power supply

 

have i covered enough or do i need to insulate the camera body away from the aluminum window frames

 

thanks

[tomcctv 187]

sorry i should have mentioned that the camera CCD board is screwed to a plastic plate inside the camera body and has about 20 mm air gap away from the aluminum body . does that change things ?

 

 

hi yes it does sorry thought you were direct to steel.

 

in 30 years i have not seen a camera damaged by lightning. i suppose its would be like winning the lottory if it gets hit.

 

 

this guys camera held ok OOOOPPs he did not.

 

 

 

[HeadsUp 0]

ouch

 

so that was a fatal ?

 

was he holding a mobile phone or umbrella in that raised arm ?

 

 

i have had equipment damaged from a lightning strike to a tree about 40 feet away , yet it found its way into the wiring of our building , could this have occurred by the strike coming up the earth wire into equipment ??

 

i wouldnt mind so much losing a camera , but the DVR cost is around $ 2500

[tomcctv 187]

hi. the pics are from the paper ouch i think the guy said OUCH twice (he should have done the lottory that day)

 

http://www.dailymail.co.uk/news/article-1382229/Man-survives-hit-lightning-TWICE-remarkable-CCTV-footage.html

 

 

 

watch the guys feet .... burns the pavement.

[HeadsUp 0]

not sure if that stain on the ground was blood . might have been other bodily fluids ?

 

absolutely amazing .

[westom 0]

My question is . can i use two lightning surge protectors on the same cable , one at the camera and one at the DVR ?

You can use all the protectors you want. Will a centimeter part inside stop what three miles of sky (the best insulator) could not? Of course not. Routine is to have direct lightning strikes without damage. But that means first learning how protection works. And why a protector and protection are two completely different items.

 

Why did lightning strike wooden church steeples. Wood was a best electrical conductor to earth. What does a lightning rod do? Provide an even better connection to earth. That wire inside a PVC pipe is now a best connection to earth - destructively via the router or server.

 

Why does a lightning rod work? Because that protector device is connected to another (most important) item - the protection. You must do same with that PVC encased cable. So that a surge does not find earth destructively inside the house, that cable must drop down and connect as short as possible to single point earth ground (the protection) before entering the building.

 

Best protection is a wire connected directly to earth (ie coax cable). But an ethernet wire directly connected will not conduct video data. So an ethernet protector connects all eight wires as short as possible to protection - earth. Only then does lightning use a path that causes no damage. Then you have implemented the same solution that Franklin demonstrated in 1752.

 

Most just know a protector works by blocking surges. The myth is popular. Routinely promoted by advertising. And is a lie. Nothing (not even the PVC pipe) stops or blocks a destructive surge. Protector either connects surges low impedance (ie 'less than 10 feet') to single point earth ground. Or a protector does nothing useful.

 

Many protection systems have no protectors. But always have a critically important part. Where do hundreds of thousands of joules dissipate? Earth ground is the only component that must always exist in any protection solution. Protectors without earthing are obscenely profitable scams. You are asking for protection; not a scam. Not some item that will magically stop what the miles of sky could not. Protection is always about where hundreds of thousands of joules harmlessly dissipate. Your questions begin with where all surge energy dissipates - the protection; not a protector. Your ethernet wire must first route down and connect to single point earth ground before rising back up to enter the building. Otherwise no effective protection exists - even with 30 protectors.

 

Other solutions also exist.

[jeromephone 6]

whatever you do provide the correct protection to prevent a person being killed or injured. Look at some of the offering from itw or diteck. We install phone systems and always provide surge protection on the power as well as co or t1 lines the over the years we have had some of the protectors fried but it has not gotten to the equipment. except in the case of a direct hit on a customers steel tower. took out all phone lines all data switches and the phone system. Protection probably prevented a fire but the voltage/amp was so great it still got the equipment. Also look at you local and national electric codes they may have some requirements.

[Soundy 1]

in 30 years i have not seen a camera damaged by lightning. i suppose its would be like winning the lottory if it gets hit.

I've only ever seen one camera damaged by lightning... in that case, the lightning hit the power mains and also fried a 16-port switch and a video card. Amazing that those three things are all that was damaged, actually.

[westom 0]

I've only ever seen one camera damaged by lightning... in that case, the lightning hit the power mains and also fried a 16-port switch and a video card.

A direct lightning strike to AC mains far down the street is a direct strike to all appliances. So all are damaged? No. To have damage means both an incoming path (ie AC electric) and an outgoing path to earth ground must exist. Once a transient is permitted inside, then a path to earth will exist. Only the best connections to earth suffer damage.

 

That is the executive summary. For homeowners who would do this stuff, numbers are always necessary. A destructive surge (that can overwhelm superior protection inside appliances) is typically once every seven years. A number that may vary even in the same town due to relevant parameters such as geology. Basic protection means superior protection already inside cameras is not overwhelmed. That is always about two paths – an incoming and an outgoing to earth.

 

In the OP's case, an ethernet wire must connect low impedance (ie 'less than 10 feet', no sharp wire bends, etc) to single point earth ground before entering the structure.

 

Other solutions are also available. Every one is about how a surge connects harmlessly to earth.

[tomcctv 187]

A direct lightning strike to AC mains far down the street is a direct strike to all appliances. So all are damaged? No

 

 

No. that depends on old or new electrical grid

[westom 0]

No. that depends on old or new electrical grid

If that statement was from an engineer, it would say why and it would include numbers. A direct lightning strike to AC mains far down the street is a direct strike to all appliances. On any grid - two phase, three phase, European, Japanese, today's, and the on a grids that existed 100 years ago. Including Edison's DC grid.

 

A lightning strike down the street is a direct lightning strike to everything connected to that wire. A 1979 Martzloff paper (figure puts numbers to it. A 100kA lightning strike to AC mains. 40kA is earthed by the primary protection system (which has not yet been discussed and should be inspected by every homeowner). 30kA seeks earth ground through other houses. And 30kA seeks earth via a nearby home. A direct strike to everything on that wire.

 

Credibility means posts with facts and numbers. Not empty accusations that only insult others who bothered to first learn the science. Science, such as Martzloff's IEEE paper, says why a lightning strike down the street means earthing is critical. So that a destructive surge does not find earth destructively inside a house via cameras, the video server, and other appliances - including the furnace.

 

A professional's app note entitled "The Need for Coordinated Protection" demonstrates why all incoming wires (including buried wires) must connect to that earth ground before entering. Because a direct lightning strike on any wire must not be inside hunting for earth destructively via appliances.

http://www.erico.com/public/library/fep/technotes/tncr002.pdf

 

Earthing necessary for that roof ethernet wire is also required by any other wire that enters a structure. That roof ethernet wire or AC wires down the street are perfect connections to appliances IF that wire is not first earthed before entering. That roof ethernet wire must be earthed (ie 'less than 10 feet') via an ethernet protector.

[tomcctv 187]

A 1979 Martzloff paper

 

like i said old or new

 

If that statement was from an engineer, it would say why and it would include numbers. A direct lightning strike to AC mains far down the street is a direct strike to all appliances.

 

 

only if on OLD overhead wire like you have in the usa. but new builds overhead THEN substation and underground to home. then no strike stops at sub so protected

[westom 0]

only if on OLD overhead wire like you have in the usa. but new builds overhead THEN substation and underground to home. then no strike stops at sub so protected

Please learn science before posting this stuff. Surges don't care if a wire is overhead or underground. Apparently you ignored the app note.

 

Since 1970, USA wires are installed underground. And still suffer surges - as was even explained in a 1959 Bell System Technical Journal paper that studied how surges work. Your assumptions are contradicted by science proven that long ago.

 

Even defined in an app note entitled "The Need for Coordinated Protection". If an underground wire entered without first connecting to earth ground, then all protection is compromised.

 

Same risk created by the roof ethernet wire. Protection necessary on all overhead and underground AC electric wires is also necessary for the OP's ethernet wire.

 

Your old and new grid assumptions even ignore surges in USA wiring that is routinely underground both before and after the transformer. How can that be? Please first learn 100 years of well proven science. Burying a wire does not eliminate surges. Same protection is required for underground utility wires as the app note so clearly demonstrated. That protection also applies to the OP's roof routed ethernet wire.

 

Age of a grid is irrelevant - except in hearsay. Overhead or underground makes no difference.

 

Other solutions also exist.

[tomcctv 187]

Please learn science before posting this stuff

 

 

 

mmmmmmmm weston your old science does not help with new science .... like i said in the post it depends on if you are on old grid or new grid. in old its >>> transformer then home no protection. new transformer then sub then home full protection

[fa chris 0]

substation should lock down strikes before sending underground to other homes. multiple homes on the same circuit from the sub station are all are subject to surges from a strike somewhere along the line.

 

There's plenty of new overhead wire hung in the US every year, air is the best insulator for transmission, buried cables lose power over long distances. Rural areas will always have overhead wiring because of this.

 

Anyways, no equipment survives a direct lightening strike. Surge protectors do exactly as their name says, protect against surges, they aren't strike protectors. Surges are going to come from close proximity lightening strikes, where the energy goes to ground through various paths which may include a steel building your equipment is attached too, or a circuit your equipment is directly connected to, the plumbing, etc. which can cause voltage fluctuations at your equipment.

 

For those reasons I always put surge suppressors on our 120vac lines going to our panels and any equipment leaving a building. We lost a lot of equipment to lightening, and surge suppressors are cheap.

[bud--- 0]

The best information on surges and surge protection I have seen is at:

http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf

- How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits published by the IEEE in 2005 .

And also:

http://www.nist.gov/public_affairs/practiceguides/surgesfnl.pdf

- NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home published by the US National Institute of Standards and Technology in 2001

 

The IEEE guide is aimed at those with some technical background. The NIST guide is aimed at the general public.

 

You can use all the protectors you want. Will a centimeter part inside stop what three miles of sky (the best insulator) could not? Of course not.

Protectors do not work by "stopping".

 

Most just know a protector works by blocking surges. The myth is popular.

It is popular with westom.

 

Protectors do not work by "blocking".

 

Protector either connects surges low impedance (ie 'less than 10 feet') to single point earth ground. Or a protector does nothing useful.

Westom believes that surge protection must directly use earthing. The IEEE surge guide explains (starting page 30) that plug-in protectors do not work primarily by earthing. They work by limiting the voltage on all conductors (power and signal) to the ground at the protector. The voltage between wires to the protected equipment is safe for the protected equipment.

 

The NIST surge guide suggests that most equipment damage is caused by high voltage between power and signal (phone, cable, ...) wires.

 

When using a plug-in protector all interconnected equipment needs to be connected to the same plug-in protector. External connections, like phone wires (and camera wires), also need to go through the protector. Connecting all wiring through the protector prevents damaging voltages between power and signal wires.

 

If using a plug-in protector at the DVR all external wires, including the wire to the camera, need to go through the plug-in protector. That is one end in the OP's question. I would also use a surge protector at the camera end. (Power supplied from a wall wart is generally more immune to surges that integrated power supplies.) I would want the ground at the protector to contact the window frame.

 

Can you use surge protectors at both the DVR and camera? Yes.

 

What I have read from people actually involved in surge protection is that a plug-in protector with high ratings and properly connected (as above) is likely to protect from a very strong, very close lightning strike (but not a direct strike to the building, which requires lightning rods).

 

Earth ground is the only component that must always exist in any protection solution.

Flying planes are crashing every day when they are regularly hit by lightning.

Or do they drag an earthing chain?

Is it only 10 ft long?

[jeromephone 6]

few planes are lost to lightening. flying into know ice, turblent winds in thunderstorms

flying in clouds when not rated and running out of fuel are a few popular ones but not lightening.

most of the time a strike is dissipates over the skin of the plane maybe taking out radios but usually that is all. Most composite planes have a wire mesh just for this reason.

[westom 0]

few planes are lost to lightening. flying into know ice, turblent winds in thunderstorms

flying in clouds when not rated and running out of fuel are a few popular ones but not lightening.

His job is to promote plug-in protectors. A $4 power strips with ten cent protector parts selling for an obscene $45 or $100+. If those products were relevant to the OP, then manufacturer specifications numbers were posted that define protection from each type of surge. Where are the always required numbers? He cannot provide what does not exist. To keep everyone confused, he discusses airplanes.

 

He only registered here because I posted here. He does this everywhere. It is his job complete with disparaging remarks. So, back to what is relevant to the OP. He claims:

They work by limiting the voltage on all conductors

Page 6 of his NIST citation says something different:

What these protective devices do is neither suppress nor arrest a surge, but simply divert it to ground, where it can do no harm.

Protection is always about where that energy dissipates. IEEE also states same bluntly in multiple standards. For example, the IEEE Red Book:

In actual practice, lightning protection is achieve by the process of interception of lightning produced surges, diverting them to ground, and by altering their associated wave shapes.

A surge current not inside a building is how all professional protection systems are constructed.

 

OP's best solution is an IEEE recommended low impedance (ie no sharp bends, no splices, etc) connection to earth. OP needs an ethernet protector to make that short connection. Then energy is not inside hunting for earth destructively via a video server and other nearby appliances.

 

Protection systems always have one component. Earth ground. Even that NIST citation says so on page 17:

A very important point to keep in mind is that your surge protector will work by diverting the surges to ground. The best surge protection in the world can be useless if grounding is not done properly.

Even the NIST defines a protector without earthing as "useless".

 

Create confusion by discussing something irrelevant: airplanes. Then nobody will demand protector spec numbers that, curiously, do not exist. OP's solution is an IEEE and NIST recommended 'diverter' from each ethernet wire to earth. Then hundreds of thousands of joules are not destructively inside the building. Protection is always about where energy dissipates. Always.

 

Other solutions for the OP's ethernet wire, based in the same well proven concepts, are also available.

[fa chris 0]

Westom, I've never seen a surge suppressor which didn't require an earth ground.

 

http://www.protectiongroup.com/ProtectionTechnologyGroup/media/PTG/ProductDataDocuments/1453-003.pdf?ext=.pdf

 

http://www.ditekcorp.com/product-details.asp?ProdKey=59

 

What type of products are you suggesting the OP use/not use for suppression? And for what applications are you recommending he use it? (ie: outside, inside, at the device, at the panel, etc.)

[bud--- 0]

few planes are lost to lightening. flying into know ice, turblent winds in thunderstorms

flying in clouds when not rated and running out of fuel are a few popular ones but not lightening.

I responded to westom - he said:

"Earth ground is the only component that must always exist in any protection solution."

Since flying airplanes do not have an earth ground connection according to westom they can not be protected from lightning.

 

I have no problem understanding how airplanes are protected.

 

His job is to promote plug-in protectors.

If westom had valid technical arguments he wouldn't have to lie about others., I have never had any association with the surge protection industry except I use some surge protectors.

 

A $4 power strips with ten cent protector parts selling for an obscene $45 or $100+.

One of the plug-in protectors I am using has a MOV with a rating of 1475 joules (plus 2 other MOVs). Provide a source for that MOV for ten cents.

 

If those products were relevant to the OP, then manufacturer specifications numbers were posted that define protection from each type of surge. Where are the always required numbers? He cannot provide what does not exist.

I have posted specs. Others have posted specs. They are always ignored.

A 10 year old could find specs. But not, apparently, westom.

 

To keep everyone confused, he discusses airplanes.

Still never explained - how do you protect a flying airplane. It does not have westom's required less than 10 foot connection to earth.

 

(Protection is somewhat like a plug-in protector.)

 

He claims:

They work by limiting the voltage on all conductors

It is not my claim. It is what the IEEE surge guide says. Read the source, starting page 30.

 

Westom says the IEEE is wrong.

 

Page 6 of his NIST citation says something different:

Everyone is in favor of earthing.

 

What does the NIST surge guide really say about plug-in protectors?

They are "the easiest solution".

And "one effective solution is to have the consumer install" a multiport plug-in suppressor.

 

Protection is always about where that energy dissipates. IEEE also states same bluntly in multiple standards. For example, the IEEE Red Book:

The IEEE Emerald book ("IEEE Recommended Practice for Powering and Grounding Sensitive Electronic Equipment") recognizes plug-in suppressors as an effective protection device. This book is about protecting electronics.

 

OP's best solution is an IEEE recommended low impedance (ie no sharp bends, no splices, etc) connection to earth.

The best solution is likely plug-in protectors, which the IEEE surge guide says are effective. The only 2 examples of surge protection in the guide use plug-in protectors.

 

Both the IEEE and NIST surge guides say plug-in protectors are effective. Read the sources. (They contain a lot of other good information.)

 

Then read the sources that agree with westom that plug-in protectors are NOT effective. There are none.

[westom 0]

What type of products are you suggesting the OP use/not use for suppression? And for what applications are you recommending he use it?

Transtector is a protector with a dedicated wire for a short connection to earth. Protection Group is a family of companies well respected for their protection. Polyphaser protectors, in particular, are legendary.

 

In every case, a protector has that earthing wire. Safety ground is not earth ground for many reasons (ie 'less than 10 feet, no sharp wire bends, ground wire not in metallic conduit, no splices, ground wire must be routed separate from other non-grounding wires, etc). Retail protectors such as Belkin or Tripplite do not provide earthing and will not discuss it. How does its 1400 joules (actually 460 joules and never more than 930 joules) magically absorb hundreds of thousands of joules? It doesn't. A joules number is provided only due to UL safety requirements. No protection claims are found in profit center protectors. A sales promoter was asked for those numbers. And again refused to provide what does not exist.

 

Transtector and Ditek have a dedicated earthing wire. Various models can be mounted outside or just inside where an ethernet cable enters. But always so that a connection to single point earth is low impedance (ie 'less than 10 feet').

 

Separation between a protector and electronics increases server protection. Telcos want that separation to be up to 50 meters (150 feet). Separation increases impedance - increases protection. Another reason why a surge will seek earth harmlessly through the nearby earthing system. And not destructively inside.

 

Transtector and Ditek connect all eight ethernet wires to earth. Only effective protectors have that dedicated earth connection. A protector is only as effective as its earth ground - where hundreds of thousands of joules harmlessly dissipate.

 

Other solutions for the OPs problem also exist.

[tomcctv 187]

Transtector and Ditek connect all eight ethernet wires to earth.

 

 

westom we have gone way off base from the ops question. first he is not on ethernet we are not talking about network

 

 

for a dvr / cameras / monitor / router by the time he has paid and installed equipment to protect it. and then not even now if lightning will still not take it out ....... he may as well just wait and see if he gets a direct hit in his life time. and if he does it will of been cheaper to replace the dvr than what it was to try and protect.

 

 

oh no whats going to happen to the 60inch tv

[westom 0]

by the time he has paid and installed equipment to protect it. ... it will of been cheaper to replace the dvr than what it was to try and protect.

Cost of installing pvc pipe was probably much more than the cost of a superior and earthed protector.

 

Best solution is to install protection the first time so that surges (typically once every seven years) do not cause damage. Not just damage to a dvr / cameras / monitor / router. Once a surge is inside a building, then anything may suffer from a destructive hunt to earth - including phones and furnace.

 

Ethernet or Cat5 - same wire. To destructive transients, even a phone line, S-video, or AC electric is same. Any wire that enters a building must first connect low impedance (ie 'less than 10 feet') to earth so that anything and everything inside a building - including all TVs - are protected. Best protectors typically cost the least. Because protectors without that dedicated earthing wire are only profit centers.

 

Other effective solutions are also available.