Unshielded CAT5 cable in EMT conduit outside?

[emptech]

I installed a system a while back where about 100 feet of cat5 cable had to be outside in the weather and in direct sunlight. I ran the cable in EMT, 1/2" metallic conduit, not waterproof. I know that unless one is using PVC conduit, glued together, the conduit will not be waterproof. A few years later we loose video and POE at the camera. I pulled in new cat5 and the customer is back in business. I ran other runs in EMT also, no problems. I finally stripped the outer insulation from the cable and noticed the orange wire (#2) felt a bit rough in the area where my TDR showed an open. I had other conductors open too. Stripping the orange wire I found the copper was falling apart. I didn't see anything obvious where the outer jacket was nicked but water got into the cat5 itself and eventually electrolysis did a job on the copper. As I said, EMT is not waterproof. I did not expect this to happen, it might happen again.

Has anyone else run into this problem? The cable was supplied by the customer, could it be cheap cable?

If this should happen again, what is a good solution? I've heard of PEX being used which can be made waterproof. Rigid conduit would work but is out of the question. I could skip the conduit and use direct burial.
or UV proof cat5?

Jim

 

[TonyR]

I know that unless one is using PVC conduit, glued together, the conduit will not be waterproof. A few years later we loose

If PVC, or any conduit for that matter, is run underground and and any part of it would be above ground, it will accumulate water over time due to thermal differntial cycling and that water will wind up in the low parts where the cable jacket will be in it constantly.

I would install a cable with a jacket rated for flooded-burial or direct burial in any underground conduit.

Lastly, insure the cable CAT-5e or 6 is solid (not stranded) pure copper (not CCA/Copper Clad Aluminum).

 

[samplenhold]

Exactly what @TonyR said.

 

[emptech]

The EMT conduit is on the roof of a building, not underground, but neverless, there was water in the conduit. There were two cat5 cables in the same conduit, so far only one cable had problems, one would think both would have problems, but given more time, it may repeat itself. If there is a problem again, would either consider UV resistant cable or PEX. It's a 200 foot run but only half of it is outdoors.

Thanks for the ideas - Jim

 

[Gimmons]

Also, use Cat6 or better. Even if some corrosion starts, it will take longer to disrupt the signal with thicker wires than with wimpy cat 5.

 

[looney2ns]

Using the proper cable for the job will alleviate most all problems.
The proper cable to be used would be direct burial rated cable.

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