How Resistance measurement insulation leak detection install and works

Resistance measurement is used to detect faults by measuring the wire resistance and the insulation resistance respectively.

Install 1.5mm cooper wire :Embed the copper wire into the insulation layer with LCH Spacer to keep the copper wire from bending

Definition of wire wire resistance

The basic principle of wire resistance measurement is that the resistance of the alarm wire per running metre is known: Approx. 1.2 O per 100 m wire (1.5 mm2).
The alarm wires are connected in a loop and the wire resistance is measured.
When measuring the wire resistance in connection with the installation, the following can be
checked:
-Broken wire
An infinite large resistance is a sign of a broken wire.
-Poor wire connection
If the measured resistance is higher than the calculated resistance of the alarm wire, there
may be a poor wire connection.
-Short circuit
If the measured resistance is lower than the calculated resistance of the alarm wire, there may be a short circuit of the alarm wires or contact between alarm wire and steel pipe.

Definition of insulation resistance

The basic principle for measuring the insulation resistance is that the electric properties of the insulation change as a function of the moisture content.

The conductivity of the insulation depends on the conductivity of the moisture Direct voltage is applied to the copper wires and the service pipe and the insulation resistanceis measured cf Ohm's law:R = U/I

Dry insulation:
There is no current between alarm wire and service pipe through dry insulation,what results in an infinitelarge insulation resistance
Moist insulation:
There will be a current between the copper wire and the service pipe through moist insulation,what results in a measurableinsulation resistance cf.
Ohm's law.

Definition af insulation resistance,continued

More areas with moist in the insulation:
f moisture is present in more areas in the pipe system as e.g. several poor casing joint connections,
the resulting insulation resistance is measured as the sum of parallel resistances:

The sum of parallel resistances may result in sections which separately have an acceptableinsulation resistance, but when summed up is a complete system with a too low insulation resistance. This may mean that the acceptance criterion for the system as a whole is not met.

It can be extremely difficult to detect faults on systems with several joints where there areinstallation moisture. It is
therefore essential that measurements are carried out from joint tojoint during installation, so any installaton moisture is
found and removed.Pipe systems with less than 1 km wire are faultless, if the insulation resistance is minimum 10
MΩ.