What's wrong with this picture?

[kensplace 0]

If that housing is the same on the inside as mine, then the camera is mounted on a plastic plate that snaps into metal guide rails. As the cam is screwed into plastic on mine, it never actually touches the metal of the housing, so grounding is not a issue (apart from cable grounds).

 

Looks like it is the same housing, but could be a different mount inside.

[phred 0]

If that housing is the same on the inside as mine, then the camera is mounted on a plastic plate that snaps into metal guide rails. As the cam is screwed into plastic on mine, it never actually touches the metal of the housing, so grounding is not a issue (apart from cable grounds).

 

Looks like it is the same housing, but could be a different mount inside.

 

Only a good earth bond will give you protection from lightning. Plastic

insulators are useless at very high voltage – the only thing that comes

close are those huge glazed ceramic isolators you see on overhead power

cables or the Soapstone blocks used at the bottom of high power

transmitter antenna - they still need special grounding in case of lightning

strikes.

Edited April 8, 2007 by Guest

[Lolo Wolf 0]

New York State has some of the best line men and electrical workers in the world, the NYC standards and safety requirements for electrical work in heavy and highway are strictly enforced. The statement of "licenses handed out for a couple of cereal box tops" based on one persons representation of their electrical/energy knowledge or lack of does not speak for the trade. Have a good and safe day.

[phred 0]

New York State has some of the best line men and electrical workers in the world, the NYC standards and safety requirements for electrical work in heavy and highway are strictly enforced. The statement of "licenses handed out for a couple of cereal box tops" based on one persons representation of their electrical/energy knowledge or lack of does not speak for the trade. Have a good and safe day.

 

Thank you for the reassurance - I know from past experience that what you say is true.

I was however, referring to licenses for security installers.

 

Perhaps a more likely explanation is that CSG is not who or what he claims to be.

[jisaac 0]

how many of you guys have had cameras that are mounted to buildings get hit by lightning?

We have never had one hit by lighting. Now I am sure that it is possible. But the likely hood of any one camera getting hit by lighting is pretty small.

The reason I was saying use the nylon screws and washers is to isolate the camera housing from the building in the event that the camera does somehow get in contact with the housing then you wont have a ground loop.

lighting was the furthest thing from my reason in using the nylon screws and washers

[rory 0]

Ive never seen it ... we get alot of lightning in the summer around here, though not as much as in the US i think ..

[phred 0]

Ok jisaacmagee, my misunderstanding.

 

Lightning is not something I would bother about here either. Doing a

proper protection job is quite involved and at the end of the day you can

still end up with toast.

 

My objection was to the pseudo science nonsense and false claims about

lightning protection and 'building zap' by CSG – I think the guy has been

reading too many Marvel comics.

In an area where lightning strikes are a real threat his suggestion would

actually make matters worse.

 

Regards

[CSG 0]

Phred,

 

The main reason for my suggestion of adding a plywood panel was to add stiffening to the mount and reduce flex.

 

The added benefit, however small, would be to provide some insulation against lightning strike. It would not help against a direct hit, or maybe even a near miss. But high voltage currents are unpredictable, even at low amperages. There are many ways stray voltages can find their way into electronics, from the power supply, to coax/wiring passing by structural beams. And since cctv cameras operate on 1 Volt PTP signal, you can see that it does NOT take many volts to zap a camera, or the DVR. How many installers have blown cameras hooking 24ac to a 12vdc cam? - many, trust me, especially before dual voltage became prevalent.

 

Since the camera is mounted on the building exterior, the Faraday cage effect you mention does not apply here, nor does it protect against transient voltages.

 

I've seen first hand, a lightning strike about 1000 feet away blow a DVR inside a steel framed masonary building. It's not dramatic, you hear a boom, look at the monitor, and nothings working.

 

Many alarm equipment installers don't connect grounds to security equipment, such as alarm panels. The manufacturers place ground connections on panels for safety/code reasons, however a nearby strike can send currents out that propagate from ground and blow the panel.

 

I don't have an engineering degree in high voltage electricity, but I know enough from experience that I would try to avoid placing sensitive electronics in direct contact with a large conductor.

 

As to my qualifications, I hold a dozen professional licenses, including Security equipment installer, and master electrician. I past president of the Metropolitan NY alarm association, and helped run the training courses for new installers getting certification. (over 60 hours of classroom alone). I run a multi-million dollar company that I built from the ground up. And your qualifications?

 

Pfred, I've installed cameras more times than you've wanked off, which i'm sure is a considerable amount , so take a hike.

 

Oh, I see your a 30 day wonder to cctvforum.com Well if you stay around long enough you will find this forum is about providing a helpful exchange of information, and not about personal attacks.

[rory 0]

Phred,

Many alarm equipment installers don't connect grounds to security equipment, such as alarm panels.

 

Yep, they dont do that down here ..

[rory 0]

Please guys .. no personal attacks .. lets keep it "clean" ..

 

Different situations and requirements exist in different parts of the globe ..

I'd bet money on it if either of you guys came down here you would have a stroke seeing the way some of the installs have been done around here (not mine!) ..

 

Thanks!

[phred 0]

 

CSG your post sums you up perfectly.

Edited April 8, 2007 by Guest

[marzsit 0]

personally, if i was going to try plywood i'd install it on the inside of the sheetmetal so it wouldn't look so nasty..... but, i probably wouldn't use plywood myself.. i'd use 2 lengths of unistrut horizontally on the inside between the building's framing and thru-bolt the camera mount thru the sheetmetal instead.

[phred 0]

personally, if i was going to try plywood i'd install it on the inside of the sheetmetal so it wouldn't look so nasty..... but, i probably wouldn't use plywood myself.. i'd use 2 lengths of unistrut horizontally on the inside between the building's framing and thru-bolt the camera mount thru the sheetmetal instead.

 

 

Good man ---- You're hired

 

Attaching the camera housing in that way will ensure it becomes part of

the same Faraday Cage so all voltages will rise and fall at the same time,

just as the experts at www.lightning.org recommend.

 

 

 

Also see this post by Rooney http://www.cctvforum.com/post-49997.html&highlight=#49997 who lives in an area where lightning is an issue.

 

 

.

[CSG 0]

CSG your post sums you up perfectly.

 

Still waiting to hear what your qualifications are Pfreddy boy?????

 

It appears that you are just a wannabe CCTV installer hiding behind an anonymous online identity.

[galen 0]

I would have to agree with Tony, that you can insulate from an indirect lighting strike. Obviously if its a direct hit nothing will stop the damage. I've seen lighting travel across the ground on wet grass. Lighting is Very unpredictable. Lighting hit outside my house and turned on my battery powered toothbrush in my bathroom. So you never know. Getting back to the focusing of the camera, I had a brand new camera that had moisture in the lens glass. I would take the camera down and hook it up on a known controlled verified good connection. All cameras should be check on a bench first anyway. This will narrow down what the problem is. If the cam checks out OK then move to the cable. Then the DVR. You should get to the source of the problem by the process of elimination.

[cctv_down_under 0]

Is your cameras lense butted up against the glass, IE could it be reflection, move the camera in the housing towards the glass as close as possible, if it is flexing it could be going out of focus, have you checked at the source that the camera is still in focus.

 

Is it possible the glass is dirty, try removing the glass front?

[mcs 0]

It looks the the lense is not tighened tpo the front of the cam, or its serously out of focus. try refocusing the camera

 

If you think its shaking to much drill and screw a piece or material to the inside of the building and it will make it more stable

 

We do this on dropceilings rather then just screw into gyprock

 

 

 

I really think its a focus issue.

try and focus it locally at the camera with a small monitor

 

I use a 4" handheld screen, does the job everytime

$ 260 off ebay

Beats the everfocus tft which blurs in the light.

[GrMt 0]

Electricity goes by the way of least resistance [when comparing different conductive materials], although not linearly.

 

All that insulating might decrease your chances of complete destruction, but I think the best solution is to get a lightning rod and ground it via heavy guage wire rope to a reliable ground source like a water pipe... away from the cameras that is. Mount the rod 7-20 feet away and above (radially) the camera and you won't have an issue with plasma burns or heavy voltage loads jumping at your camera. You may be asking why this will work, and the answer is simple. You are comparing the resistance of humid air to iron, not the aluminum siding of your building.

 

Just a thought, because although you can't stop lightning, you can divert it!

 

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Rochester/ASU ME/ECE/PHY 2009