Hi All

 

Is there a protocol for testing the effectiveness of alarm cable.  I have a property which has cable already in place but no alarm and the owner wants me to wire in an alarm.  I have no idea how old the alarm cable is or what state it is in.   I am familiar with the testing of domestic cable using continuity and insulation resistance testing.  Do I just do the same thing for alarm cable to test if it has deteriorated over time? If so what sort of measurements should I get?

 

Thanks in advance for your help.

 

Pete

yes but as it 50v cable lower the insulation test

good cable will give 10 ohms per hundred

Would the lower IR setting on a megger be acceptable - mine is 250V?  Or would you use the ohmmeter setting on a multimeter? Thanks

 

Cable will only take 50V max.

Multimeter would be my tool of choice.

Ok. Thanks.

 

as 6wb id rely on a multi meter first

You could always but a caviat in your quote stating cable routing & installation has been installed by a third party

As above, the norm would be to make sure the cables meter out, there's nothing obvious maybe lift a couple of carpets near the door jambs to check for damaged, poorly run cables.

 

Once you are happy, make the customer aware they are paying a lot less by you utilising existing cabling and document it and the fact it's not covered under any warranty, on your spec refer to each device as 'utilising existing cabling' too, this is the norm in this type of scenario.

I must admit if the existing system is just 'old but not broken' I highlight the no warranty on old cable rule, have a good look for carpet wires etc... and also as each old device comes out,

and by the time you view EOL resistance at the panel and measure voltage at each device you've got a good idea of what's what.

Use a 25v / 50v Insulation resistance tester