Water or fog inside the camera
very common
“There's water sitting in the bottom of the dome, or it fogs up every morning and clears by noon. Picture's like looking through a shower door.”
Likely causes
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No drip loop: water tracks down the cable into the housing
most commonThe cable approaches the gland rising, so every drop running down the jacket arrives at the entry. Water pooled in the base with a clean, correctly seated gasket usually means the cable, not the seal.
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Conduit acting as a moisture path
commonConduit from a warm interior, or an underground run, terminating at the camera and condensing inside it. The housing is sealed and full of water anyway. Look for an unsealed conduit end and no drain.
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Gasket pinched, trim ring unseated, or screws unevenly tightened on reassembly
less commonThe problem starts right after somebody worked on it. Look for a gasket sitting proud of its channel, a witness mark in the wrong place, or bubble screws at visibly different depths.
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Desiccant exhausted
Fogs internally at dawn and clears as it warms, worse as the unit ages. The pack is saturated and it is not coming back: it is a maintenance item with a life.
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Unused gland or knockout left open
An empty gland with no blanking plug, or a spare knockout open to the weather. Ten cents of plug, one dead camera.
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Mounted so that water sits on the seal
Housing with no fall, or a dome catching runoff from a gutter or parapet above it. Sealing surfaces are designed to shed water, not to sit submerged in it.
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Cracked bubble, failed gland, or a UV-degraded sunshield seal
Fine crazing or a hairline crack, or a gland nut that has never been tightened onto the jacket diameter it is sized for.
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Pressure cycling drawing moist air in
Repeat fogging with no visible ingress point. Day/night temperature swings breathe the housing through its least-sealed point, which is what the vent membrane and the desiccant exist to manage.
What to bring
- Ladder or lift
- Correct drivers and a torque driver
- Replacement gaskets and bubble
- Manufacturer-specified desiccant packs
- Blanking plugs and correctly sized glands
- Lens cloth
- Camera and job file for photographs
Safety
Work at height, with the camera open and both hands busy: set the platform under it and do not reach. Kill power at the switch port before you open a housing with water in it, and do not re-energise a wet housing to see what happens. With the bubble off, do not look into an active IR array: near-IR produces no blink or pupil response, so nothing warns you that you are overexposing your retina.
Steps
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Step 1: Kill power at the port, then open it and photograph the water line before you dry anything
Where the water sat tells you where it came in. A pool in the base with a dry lens ring says cable or gland; water on the seal face says the seal or the mounting attitude. Take the photograph now: it is evidence and you will not get it back once you wipe it.
If that doesn’t do it
No standing water, only internal fog: go to desiccant and pressure cycling.
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Step 2: Make a drip loop and check the gland
The cable must approach the gland from below so water runs away from it. Free, two minutes, and it is the single most common cause. Confirm the gland is sized for the jacket diameter and tightened onto it with no spiral gap under the nut.
If that doesn’t do it
Drip loop correct and gland sound: look for other openings.
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Step 3: Blank every unused gland and knockout, and seal the conduit
A proper blanking plug, not tape. An unsealed conduit is a moisture pipe from wherever its other end happens to be, and it will condense inside the camera regardless of how well the housing is sealed.
If that doesn’t do it
All sealed: dry it out properly.
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Step 4: Dry the housing properly and fit fresh desiccant
Not a wipe. Get it genuinely dry, fit a new pack of the type the manufacturer specifies, and reassemble immediately so it is not absorbing ambient moisture while you finish the paperwork.
If that doesn’t do it
Dried and re-desiccated and it returns: reseat the seal deliberately.
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Step 5: Reseat the gasket and trim ring deliberately
Gasket clean, seated in its channel with no twist, no grit, no pinch; screws in sequence and even, to the manufacturer's torque where one is given. The ingress rating is void from the moment the bubble comes off until that gasket is correctly reseated, which matters, because troubleshooting steps all over this discipline tell you to take the bubble off.
If that doesn’t do it
Correctly sealed and still ingressing: look at the mounting attitude.
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Step 6: Fix the mounting attitude if water can pool on a seal
Fall away from the seal, sunshield fitted and sitting correctly, nothing above it dumping runoff onto the dome. Relocate rather than trying to fix a bad position with mastic.
If that doesn’t do it
Attitude correct and it still fills: replace the housing or the bubble and check for crazing and cracks.
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Step 7: Retest after real weather and record it
Look again after the next proper rain and the next cold morning, not just before you leave. Note the model, the desiccant type and the date in the job file, and put desiccant replacement into the maintenance schedule.
References
- IEC 60529: ingress protection (IP) code
- IEC 62676-4
- NFPA 70 (NEC): wiring methods for damp and wet locations; confirm the adopted edition