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    Cool Your thoughts

    I've had a run of cameras dying in/after electrical storms lately & I'm wondering what thoughts you have on hardening them against this occuring.
    The last group was four internal domes & an external full body in aluminium housing. There are 16 cameras in total running off 4 SMPS running off a UPS. When there is a problem it is always about 4 or 5 cameras that die. There doesn't seem to be anything common that would point to the cause. It is not always the same cameras , nothing common as far as which SMPS is supplying them , some will be mounted on gyprock ceilings & others on building metal work.
    One company I do work for insists on insulating cameras/housings from building metalwork. When I asked why he could not tell me other than someone had told him it should be done that way.
    Having checked out a few cameras it would seem that for domes & FBs the electronics are insulated from the housings anyway. Anyone got any ideas or suggestions or is it just the crap standard of modern day electronics



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    Quote Originally Posted by watchdog View Post
    I've had a run of cameras dying in/after electrical storms lately & I'm wondering what thoughts you have on hardening them against this occurring.
    Lightning can reach the installation by three means of access. Of the three listed below, the latter two are introduced via the ground system of an installation (e.g. Coax shield).

    1. Excess Voltages due to strikes on lines.

    Lightning strikes on overhead lines lead to over voltage of several thousand volts spreading onto the HV and LV networks.

    2. Excess Voltages due to feedback from earth.

    A lightning strike on the ground causes an increase in the earth potential, which can spread to the installation (fed back from earth/gnd circuit).

    3. Excess voltages due to electromagnetic induction.

    Associated with lightning discharge is an electromagnetic field with a wide frequency spectrum which, as it connects to the loops in the installation, will give rise to destructive induced currents.

    Quote Originally Posted by watchdog View Post
    The last group was four internal domes & an external full body in aluminium housing. There are 16 cameras in total running off 4 SMPS running off a UPS. When there is a problem it is always about 4 or 5 cameras that die. There doesn't seem to be anything common that would point to the cause. It is not always the same cameras , nothing common as far as which SMPS is supplying them , some will be mounted on gyprock ceilings & others on building metal work.
    This will be a simple case of survival of the fittest with the weaker of the species dying.

    Quote Originally Posted by watchdog View Post
    One company I do work for insists on insulating cameras/housings from building metalwork. When I asked why he could not tell me other than someone had told him it should be done that way.
    It doesn't make one iota of difference if the camera is isolated from the building or not in electrical storms. The real culprit is the coax shield.

    Isolating the camera from building metal-work will help reduce ground loops in a system, but do sfa in the event of lightning strikes.

    Quote Originally Posted by watchdog View Post
    Anyone got any ideas or suggestions or is it just the crap standard of modern day electronics
    It depends on how much are the cameras worth and how often are they knocked out due to lightning. If it is an expensive installation, you might want to look into products from .

    If the system is relatively cheap, you might find lightning arrestors are not economically viable.

    Unfortunately we live in a throw away society with quality being the victim.

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    Some light reading for those interested in the matter.


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    Cool

    If it was a case of induced spikes in the coax or earth voltage gradient from a nearby lightning strike then surely the DVR would be just as likely to suffer. If it was a lightning strike on the mains then surely the UPS & certainly the SMPS should suffer as well.
    Maybe an un earthed system would be the way to go.

    On a side note the FB camera was one I got from Rhino a couple of years ago to try out. It boasted a "lifetime warranty". I rang Rhino this afternoon & they said send it back & we'll repair or replace. I'm a big believer in warranties .

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    Rhino sell some innovative gear, but a lot of their cameras would well and truly fit into the weaker category George referred to. I wonder if that explains the symptom?

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    Individual fused powersupply?

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