Wire testing device perhaps

[tataylor1]

Hi all.

If anyone can help me with this it'd be great.

I have lots of wires around the house that are the beginnings of a wired burglar alarm setup. They are a pair of wires in each room and at doors etc, bare ends sticking out of the ceilings, and working their way back through the floor/wallspaces to a single exit where there are lots of cables all just bundled up.

Nothing is labelled, so is there a gizmo one can buy that I can connect to either end of the wiring to test which end corresponds with which? I was thinking a 9v battery and a modelling lightbulb but if there is an actual tool for this scenario it might be good to get.

Bearing in mind one end of the wire could be 3 rooms away from the other.....

Thanks all.

 

[securespark]

Use a digi multimeter set to continuity at one end & twist a pair together at the other?

 

[tataylor1]

ouch so simple i feel foolish. thanks!

 

[securespark]

http://www.maplin.co.uk/store-locator/south-east-region

http://www.maplin.co.uk/productsearch?criteria=multimeter

 

[Taylortwocities]

To save you running around the house.

You'd be better off with a battery doorbell
something simple like THIS



Connect it on the end of one cable, then go round your house shorting out the ends until the bell rings.
Mark the cable, then move on to the next one.

 

[Taylortwocities]

Duplicate, how did that happen

 

[securespark]

I did think of that, but thought that if tat1 needed to buy a battery doorbell , it would be better to get a DMM.

 

[SimonH2]

If there are lots of identical cables it can be tedious going through the bundle time and time again to find the one you've shorted out at the other end. Quite useful is a tone set as used by (amongst others) telecoms engineers. Clip it on a cable in one of the rooms, then you can quickly find the other end of that cable in the bundle by sound. As a tip, when you think you have the right one, just short the two wires with the side cutters - if you have the right cable the sound will stop (you're shorting the tone out), but if you have a ghost signal (one inducted into another cable) then the tone will still be around.

A couple fo videos :
http://www.youtube.com/watch?v=jP0AtN9hTP4
http://www.youtube.com/watch?v=apIpHPgkevQ

 

[tataylor1]

thanks all for the replies, really helpful to get some more knowledgable insight into a problem. saved me a lot of time!

 

[ban-all-sheds]

If there are lots of identical cables it can be tedious going through the bundle time and time again to find the one you've shorted out at the other end. Quite useful is a tone set as used by (amongst others) telecoms engineers.

Or an assistant.

 

[Taylortwocities]

Those don't look like GS38s!

 

[securespark]

Trust you to stare at her tips!

 

[tataylor1]

It's hard to resistor. I can see her positive points. I'd hitch up to her volts-wagon. etc.

Watt?

 

[securespark]

You forgot to say that you'd love to take her ohm.

 

[tataylor1]

boom boom!