Is there any way of confirming whether an exposed Micc cable is powered up.

There appears to be no access above or below a rising main cupboard so all we have is a group of micc cables.

We need to know if they are Live or Dead. Is there an easy answer without disturbing the cables.

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keithredpath

not that i know of, the copper sheath stops the voltsticks from working, so you have to have access to one end where its terminated.

oh, so spiking them isn't acceptable then?

If they're carrying significant current (not exactly the same as being live of course!) - they would be a little warmer than ambient - a couple of thermometers and a bit of thermal insulation might give an indication.

On the other hand - what would you do if you knew for certain they were live? If the plan is just to leave them alone, then is there any harm is just presuming that they're live?

If the ends aren't accessible - would there be a question over the ownership of the cable?

- Andy.

CAT Scanner perhaps might give you an all or nothing idea ?

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Empty barrels make the most noise.

Not sure it would CAT scanner would need to see the 50hz field to indicate and that's enclosed in an earthed metallic screen.

Stu

But the screen being copper might not block the electromagnetic field Stu? Just a thought, don't know if that's correct thought,

Dave.

With my radio hat on, MICC is no different to Coax (well ok, impedance etc is but...) and good coax lets nothing out.


Stu

That's RF though Stu, a bit different to 50Hz I would guess? (interesting thoughts though, you with your radio hat on and me with my ex TV engineer hat on!)

Dave.

Very true.

Going to have to play now, well actually tomorrow as I've got a 100m run of LDF450 (proper coax) to install for the fire service.

Once I've got connectors on it and before I connect the antenna, I'll introduce some 50 hz and see what happens with both the voltstick and the CAT.

I know where there is some MICC as well so if no one manages to play before I pass the site I'll play the same game there.


Stu

Be sure to let us know the outcome Stu, just for curiosity's sake!

Dave.

Hi Stu

Proper coax indeed!

That's a long run to an aerial, do they not mind about the attenuation? I'm assuming there that it is for UHF comms and not AM band radio...

Cheers!

Clive

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Clive S Carver GCGI IEng MIET

If you dont know if they are live or not, you treat them as live.
Arrange withthe client for thevrequired access etc totrace the cables and identifybaccordingly

intresting CAT will pick up old lead cables underground though

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!

i think you mean CAT as in 'cable avoidance tool' not CAT scan as in computed axial tomography which is a million pound tool as compared with 400 quid????

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry

yes cheapo CAT, ill maybe get the £1m tool from Santa though

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!

My Fluke volt stick has CAT II printed on it.

Is it detecting that it's live, or just that it's metallic?
- Andy.

and i have 2 CAT (brother and sisters) since they were kittens. Just shows you there is many different types of pussy out there

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Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!

Kittens do make excellent voltage indicators.

Sufficient inteference will get onto the outer sheath for it to be picked up by a CAT. A 50Hz signal is very good at getting on to anything metallic and there will be sufficient to pick up from a cable sheath whether it is live or dead. The only way to positively identify a cable is using signal injection, but that usually involves access to both ends of the cable as well as making it dead.

Regards,

Alan.