Re: [nznog] Temporary fibre cable across Wanganui river near Harihari - anybody got photos?

At 10:12 a.m. 4/01/2013, jon.brewer wrote:

On 4/01/2013, at 0:56, yuri wrote:

...

I hope you're only using grease-filled outdoors. The sheath on most ordinary indoor cables is hygroscopic.

These days the good outdoor CAT5e has a white paper ribbon inside that swells up in the presence of moisture. Much nicer to work with than grease-filled cable.

indoor cat 5 lasts over 10 years outside. Eventually the sun gets the blue jacket, just as it gets the nylon blue outer sheath on fiber. (the nylon is so that it pulls thru ducts easier). The nylon lasts about 2 years, but cat-5 lasts 10. Theres some in my garden thats been there nearly 20 years. With the outdoor cat-5 stuff make sure you put a earth bond on the black sheath. It can be either PE or PVC and if deployed aerial, the wind causes loose electrons on the sheath. PVC is worse. PE will still cause some. Bonding can be a few turns of bare copper wrapped round the sheath, then taped over with pvc tape. If you run it into a house thru a tight-ish hole that will be as good. We used to have pole mounted ethernet switches at CityLink and lost a few due to static. There was a range of termination PCBs we made that had power steering diodes and surge suppressors on them. I don't think they use them now. Too technical and no one likes climbing poles. There are no issues with the signal conductors tho. All ethernet ports have a 1500V isolating transformer on them, its part of the spec and why the power levels on POE are so low - to avoid saturating the magnetics in the transformer. On our non-ethernet system we get 60watts of power down cat-5. Its how we power our cameras.