Industrial Multicore control cables

[john h owen]

How do you test mulicore control cables to check the supply is isolated to disconnect the limit switch /sensor/junction box with klippon terminals with twenty - thirty cores in there to check non are live could be ac or dc?

 

[Knobhead]

Normally I would just check the cores I’m interested in. It’s rarely possible to isolate the entire cable.

To be honest on the plants I worked on you would do it live, saved walking half a mile back to the switch room and back.

 

[john h owen]

Yes I understand what you are saying,but I mean a method you would use to check cores are not live if you had to remove any of the mentioned items.

 

[Knobhead]

Just check the cores your interested in:
A/ to earth
B/ between cores

If for example you need to replace a change over limit, common will be the live feed. You will find the live feed by testing and referring to the drawings. Disconnect the feed first, re-connect last.

You have to remember when testing for a fault you will be normally be working live.
Exercise is one thing when going to isolate. When you’ve got the plant manager screaming over the radio at you, speed counts.
Most control systems will be 110V or less which is why I’d work live.

PS if this has anything to do with collage scrub the “live” bits!

 

[john h owen]

The job was to remove Electrical and Mechanical Systems at a plant it all had to come out,and they were putting new equipment in later.The main panel for the system had been Isolated and they wanted a Electrician to verify that all the cables were dead before they touched anything in case of shock risk.The Electrical System had sensors /motors/junction boxes to check before the cables could be disconnected.
So I had a mulimeter what I did to ensure this was check each core to earth on ac/dc and then chech between all the cores on ac/dc.

 

[netblindpaul]

Test at the supply, if this is isolated then all the kit fed from it will be off!

 

[Knobhead]

I hate playing 20 questions, why weren't the facts given first?

 

[john h owen]

It was a proceedure they wanted to carry out to ensure cable cores were dead the mechanal team needed this assurance, I was only intrested in other peoples views on testing for dead

 

[plugsandsparks]

Slight thread diversion but this reminded me of a notice i saw today, TBH you have these things in front of you but never see them and then today i saw on the cover of a DB, "isolate before removing cover". This was on a 36 way TP board, i was fitting one extra heater. I have worked live since being in my teens and never think anymore about it but does every one else do the same or should i have asked for the factory to stay open for a long evening so i could run a cable to a breaker.
I wonder what they say in college.
BTW was a MG Isobar, doddle really...

 

[johnboy6083]

In my experience, you would be severley ridiculed if you refused to add a circuit to a DB whilst live! I'm not saying that you should be, but I'm happy to work in live DB's, but I asses the risk first, and if there is exposed busbar, or exposed neutral rails (I've had a bolt from them before), then I won't do it.
I'd respect anyone that says they won't.
Those people would never be able to fault find on industrial panels ect though, aas that is routinely done live.

 

[netblindpaul]

You can "legally" fault find and test live without issues.
The "H&S" requirements stop you "working" live to modify or repair circuits.
The "BODS" that is the "powers that be" NEED to begin to understand that this is the way it will have to be.
It can be designed out of the kit so that it is safe to do.
An MG DB is "almost" there.

 

[Guest111]

The HSE state that there are very limited circumstances in which live working is permitted, however as someone who was qualified as a supervisor to HSE requirements I can only say that I wish they would be as proactive in situations where they need to be as they are officious in situations where common sense should prevail.lets be honest here most of us work live at times,and if proper precautions are taken and you have sufficent experience and skill imo it is no more dangerous than crossing the road.I was once told by my boss after travelling a good distance that the whole team would have to abandon job as someone had forgotten to leave keys to switchroom, whole job stopped all because we had to reroute a 2.5 radial, well these thing happen and I decided it was safe to work live,used common sense job done everyone happy and I,M still here.

 

[netblindpaul]

phil,
I am VERY aware of the HSE issues around live working, I don't need you to tell me those.
I would be interested to know which qualifications give you the right to claim to be qualified as a supervisor under the Health and Safety Executive requirements, along with what those requirements are.

 

[Knobhead]

Phil, you have PM's

 

[Guest111]

phil,
I am VERY aware of the HSE issues around live working, I don't need you to tell me those.
I would be interested to know which qualifications give you the right to claim to be qualified as a supervisor under the Health and Safety Executive requirements, along with what those requirements are.

My qualifications on that subject come from working in a government department at that time,which for certain reasons must remain nameless I am not prepared to rise to the bait on this one,we would all like to live in your ideal world,where everything goes the way it should but unfortunately we don,t.Do I detect an air of being a tad peeved in your post?couldn,t possibly be because someone else knows a bit could it?You see my friend I come one here to help people where possible however I have noticed that you seem to pop up only to criticise others or to promote your own business.