There are weatherproof connectors that a compression with a rubber grommet to compress around the wire. SJ connectors are what they're called. I use those with Duct Seal, a flexible, waterproof, putty used by electricians. Both are available at most "big box" home improvement store, Lowes or Home Despot.
To get one small enough to pass through the appropriate rubber bushing you may well have to crimp on a new end. The Dahua boxes I have purchased came with a similar type piece just made out of white plastic.
Well, given that the hole is made for 18/3 or 16/3 SJ cord, typically, they don't crimp tight which is why I mentioned Duct Seal. An RJ connector, let alone one with a WP housing on it won't fit through it. Lowes and Home Despot may, or may not depending on local demand and inventory, have them in stock. Amazon may be a better choice or a real electrical supply house.
True, but then you lose the advantage of a rubber lined bushing to prevent chaffing of the cable. Alternately, add a few wraps of good electrical tape around the cabe, at the point where the bushing is, to let the bushing clamp down on the cable
You might want to consider silicone rubber. It pretty tough stuff and if you make a 'grommet' shape out of it around your cable it will help keep the cable from moving at all, provide a cushion between the hole edge and not be prone to falling out like duct putty.
I am in the middle of an outdoor project adding 2 more cameras and 4 IR illuminators in the woods.
I found a product called 'Liquid Electrical Tape' by Permatex: Amazon.com: Permatex 85120 Liquid Electrical Tape, 4 oz: Automotive
I used it to seal the wires going through the compression fittings of my boxes. Messy stuff but it sets up with a nice seal.
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