Home
JAQForum Ver 24.01
Log In or Join  
Active Topics
Local Time 19:09 23 Jul 2024 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : SMALL UPS...

     Page 4 of 4    
Author Message
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3791
Posted: 06:56am 18 Jun 2024
Copy link to clipboard 
Print this post

Hi Grogster,

I would investigate looking into the datasheet of the cable.
It will show to what standard the cable is tested.

Using an insulation tester is risky since when it arcs you essentially lost a cable (at least that pair, but maybe adjacent as well). You can use the Impedance test function at 500V, but since you know it is a telephone cable, with 48V nominal, and 90V ring voltage, a test voltage of 500V may even be too much.

But testing every pair to be used at 100V should be okay, and even advisable.

Volhout
PicomiteVGA PETSCII ROBOTS
 
Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 6012
Posted: 07:00am 18 Jun 2024
Copy link to clipboard 
Print this post

I'm not sure about 1000V on telephone pairs, but most wire will easily take 3x the working voltage that it's normally used for, in my experience.  :)  That's why I suggested 250V. 3x the 90V ringing voltage isn't far off.

One has to live *just slightly* dangerously to have a bit of fun. :)

DO NOT clamp one tab of an OC35 in a vice, connect the vice to neutral then dab live onto either the base or emitter. They go bang and the top flies off at very high speed, embedding it into the wall. NEVER, EVER DO THIS, girls and boys. It's dangerous. :)  (Yes, I've watched it being done!).
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Grogster

Admin Group

Joined: 31/12/2012
Location: New Zealand
Posts: 9197
Posted: 07:45am 18 Jun 2024
Copy link to clipboard 
Print this post

Hey, Volhout, and happy to see you post again.
I had a sudden thought that my "No no no" post might have been offensive to you - certainly not my intention, but I did think about that today!      

@ Mick: Yeah, I must admit I never ACTUALLY tested at 1000v - that was just what the mega was capable of doing.  I would test at 250v, and if that was suspicious in terms of insulation breakdown, I would test at 500v.  Nine times out of ten, if the 250v test was suspicious, then the 500v test would show total breakdown, so that pair was taken out of service, marked as "Faulty" in the records, and the service in question was transposed to another good pair.

Sorry to all of you reading this, not really familiar with the telephone cable faults lingo!  

  Mixtel90 said  DO NOT clamp one tab of an OC35 in a vice, connect the vice to neutral then dab live onto either the base or emitter. They go bang and the top flies off at very high speed, embedding it into the wall. NEVER, EVER DO THIS, girls and boys. It's dangerous. :)  (Yes, I've watched it being done!).


Crikey!    

Ah....no - don't do that!

EDIT: I will see if I can find the old mega I used to use, and I will post details and a photo here if I find it.
Edited 2024-06-18 17:56 by Grogster
Smoke makes things work. When the smoke gets out, it stops!
 
     Page 4 of 4    
Print this page


To reply to this topic, you need to log in.

© JAQ Software 2024