SWA fault.

[telectrix]

never seen anything like this before. new cable supplied by cient, installed by ne. no probs. 2 weeks later get a call.. no power. continuity test proves brown conductor is o/c. client is in a catch22. has to return cable for replacement involving me 2 call-outs.... as a temp. measure, i rejigged it, using grey as L, BK as N, and armour as sole cpc. 8 wweks down the line, call to MCB tripped and won't reset. this is what i found after dissing the SWA completely.

cable was laid on ground prior to client digging trench, no chance of external damage. any ideas, apart from faulty manufacture?

 

[Andy78]

There is one thing about that picture I would stake my sandwiches on... and that is that the cable has been cut. The armourings are too neat for it to have been crushed. Whether saw or croppers I'm not sure but that's certainly no fault explosion that has parted that cable.

 

[SJD]

Looks a bit like a SWA cable a customer of mine had "rotovated" by the gardeners prior to putting in a new lawn, while the cable was laid on the ground to one side under the bushes.

 

[mache]

100% not a manufacturing fault with such clean separation and lack of longitudinal distortion in the armouring and cores. Either malicious damage by persons unknown or something heavy and metallic dropped or unloaded on top of it being that it might not have been visible being hidden by the hedge.

 

[telectrix]

so how do you account for the open circuit of 1 conductor some 2 months ago. if the cable had been damaged like you say, why is there no sign of rust on the steel?

 

[SJD]

so how do you account for the open circuit of 1 conductor some 2 months ago. if the cable had been damaged like you say, why is there no sign of rust on the steel?

So perhaps there have been two separate "incidents"? I'm not an expert on SWA but for the first fault, could it have got stretched e.g. when laying the cable out with the wrong sort of handling, and the second fault is unrelated to the first e.g. something mechanical driven through it?

 

[telectrix]

the cable was laid by me and definitely not mis-handled. where it was laid it was impossible for anything to accidentally get near it.site is occupied 24/7. any attempt to steal cable, the damage would be close to one end. not slap bang half way along. i'm going back to cut the section out. something just does not add up.

 

[Deleted member 9648]

A space ship landed on the cable,or possibly an asteroid. No other possible explanation.

 

[telectrix]

A space ship landed on the cable,or possibly an asteroid. No other possible explanation.

got to be. an alien thermic lance. like it.

 

[Lucien Nunes]

Have you checked whether the brown core is O/C in one half as it now stands? I.e. prove that the faults are unrelated. I've seen a few blown-up things over the years and that doesn't look like any of them!

 

[telectrix]

funny thing is that the steel armour has either been cleanly cut or was never continuous.

 

[PEG]

Evening Tel,that particular damage does not look to be a manufacturing fault. Any production mishaps,are usually visible,once dissection can take place,and are usually associated with one part of the process,say core insulation. That,to the best of my vision,looks mechanical. That,coupled with the fact i have grown up,socialise and work for the folk we are talking about,makes me absolutely shock-proof in the guess-the-story game! I have seen exactly the type of damage in your picture,and it was caused on one occasion by an axe,and the other by an excavator bucket wear-plate. The initial core failure could have been a cable fault,unrelated to this issue. Also,do not rule out someone thinking the cables dodgy,due to the first fault,and MAKING sure it will be changed,by "instigating" the second. I have seen this on MANY occasions. This is almost standard practice in the vehicle bodywork repair/insurance job. I would want to SEE the initial failed part of that single core first,and personally,would not move further in the mystery until i had. No need to point fingers,i've had the gloves on myself,and it's less fun than cable fixing! Would love to know outcome fella,and if you strip it to find that core,can i have a pound for every time someone asks "What ya doin wiv that cable pal?..." :bobby:

 

[Scotford14]

I agree With Lucien. Do a continuity test on the remaining halves of the cable to prove the original fault (Br O/C) is their. If not then the picture you have provided is the cause of the first fault.
If you believe the armouring was already damaged from the manufacturer. You could calculate what the resistance of the armouring should be over the length of the run you have and then compare to any original test results you have?

James

 

[mache]

funny thing is that the steel armour has either been cleanly cut or was never continuous.

Well it's guaranteed it was continuous when you laid it, have a look at some videos of cable production and you will understand how it would be impossible for it to come out of manufacture like that.

 

[telectrix]

might have found the culprit.

 

[dingledong]

7 ft rat