Camera drops or whites out when IR engages

Likely causes

• PoE budget or port allocation insufficient for the night load

  most common

  The reboot lands within seconds of the day/night transition. You can usually hear the IR cut filter swing OUT of the optical path and the array energise together. Port draw jumps toward the class limit and then the port drops. Bench the same camera on a local injector and it survives the night.

• Voltage drop over the run: long channel, fine-gauge cordage, or copper-clad aluminium

  common

  Runs fine on a short cord at the TR, fails on the drop. An 802.3af PD needs at least 37 V at its input and a Type 2 PD at least 42.5 V, so the DC loop resistance of the whole channel is the budget you are spending. Check the cable print for CCA: it is not a listed or compliant conductor for this application, so it fails on listing before you even reach its higher resistance and its brittleness at terminations. That is the argument that holds up with the customer who paid for it.

• Not a reboot at all: IR bloom off a near-field surface

  less common

  The stream never drops; the image just washes out. Cover the near object, or put your hand near the dome, and the exposure recovers immediately. Classic on a wall-mount dome with the bubble close to a soffit, gutter or handrail.

• IR scatter inside the dome bubble: missing foam gasket or unseated trim ring

  Uniform milky haze across the whole night image, usually worst at the top. View without the bubble and the image goes clean instantly.

• Insects, webs or condensation on the bubble

  Bright blobs that drift, or whiteout only on still nights. Wipe it and it is fixed until it comes back, at which point it is illuminator placement or water ingress, not a camera fault.

• Shared multi-camera power supply at its limit after dark

  Several cameras on the same supply misbehave together at dusk and are all fine at noon. Meter the supply output under night load and watch it sag.

• Heater or defroster cycling on a cold night

  Fails below a certain outdoor temperature rather than simply at dark. The data sheet lists a separate figure with the heater running. Look it up; it is often far above the nameplate figure and it varies widely between models.

What to bring

• Switch management access with per-port PoE reporting
• 802.3at/bt compliant PoE injector and short stranded patch cord
• Multimeter
• Camera data sheet showing maximum power with IR and heater, by exact part number
• Lens cloth and blower
• Ladder or lift

Steps

1. 1

   Step 1: Force night mode in daylight

   Set the day/night profile to manual night, or hood the sensor. You want this reproducible at 2 pm on the ground rather than at 11 pm on a ladder. Survives forced night mode indefinitely but still fails at dusk in the field means the trigger is temperature or the heater, not the IR.

   If that doesn’t do it

   Will not reproduce: schedule a night visit or pull the camera log in the morning.

2. 2

   Step 2: Read PoE draw at the switch port before and during IR

   Note the delta, then compare it against the data sheet's maximum-with-IR figure (and maximum-with-heater) for that exact part number. Array power varies enormously between models, so the delta only means something next to that camera's own figure, and the idle draw tells you nothing. Compare the night total against the port limit and the switch's total budget: a switch that balances at noon will shed ports at dusk.

   If that doesn’t do it

   Draw well inside budget: move to voltage at the camera.

3. 3

   Step 3: Power the camera from a compliant injector at the camera end

   Disconnect the drop from the PoE switch port, or administratively disable PoE on that port, BEFORE you connect the injector. Never leave two PSEs on one channel: with a passive or non-compliant injector in the mix that is a real path to a damaged injector, switch PoE controller or camera PD front end, and it invalidates the test anyway because the camera may still be drawing from the switch. Then run the camera on a 1 m cord straight off the injector, with the drop out of circuit. Survives the night means the delivery path. Still fails means the head or its IR board.

   If that doesn’t do it

   Still fails on a local injector: swap the head.

4. 4

   Step 4: Check the PoE type and class the camera actually negotiated

   It should match what the data sheet calls for. A Type 3 or Type 4 camera on an 802.3af-only port will often run all day and die the moment the IR loads the board. Type 3 delivers up to 51 W at the PD and Type 4 up to 71.3 W. Mixed-vintage switches in one rack are the usual trap.

   If that doesn’t do it

   Type and class are correct: inspect the cordage and cable.

5. 5

   Step 5: Inspect the cordage and read the cable print

   Use a stranded bare-copper factory patch cord, 24 AWG or heavier, and keep it short. Solid conductor belongs in the permanent link only: it work-hardens and fractures at the plug strain relief, and solid and stranded plugs use different contact geometry, so the wrong pairing gives you a high-resistance intermittent, exactly the fault you are chasing. Fine-gauge 26-28 AWG cords are permitted, but only at reduced length, and they eat DC resistance margin that only bites under night load. Shorten them first, up-gauge second.

   If that doesn’t do it

   All stranded copper and correct gauge: certify length and DC loop resistance.

6. 6

   Step 6: Pull the bubble or front glass and look at the night image

   Force day mode or kill power to the illuminator before you put your face in front of the lens. If the stream never actually dropped and the picture only washed out, this is optical, not electrical. A clean image with the bubble off means a missing IR gasket, an unseated trim ring, webs, or a surface close to the lens bouncing IR straight back. The ingress rating is void from the moment the bubble comes off until the gasket is correctly reseated.

   If that doesn’t do it

   Still washed out with the bubble off: reaim, or go to external illumination.

7. 7

   Step 7: Reaim, or remove the near-field reflector

   Get the wall, soffit, gutter or handrail out of the bottom of frame. IR falls off with the square of distance, so anything close dominates the exposure and the camera stops down for it. If the scene cannot be reaimed, disable onboard IR and fit a separate illuminator offset from the lens axis.

   If that doesn’t do it

   Still unusable: the scene needs designed illumination, not a camera setting. Price external IR or white light and put it in writing.

Check it with a calculator

• Channel & PoE Check length and power

More Video Surveillance guides

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• Motion recording triggering on nothing
• Customer can't view the system remotely
• Water or fog inside the camera
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