Multimeter Tests
148 MAX-635G
Stressed Balance
Stressed Balance
Stressed Balance is an optional test that continuously generates high
voltage (135 VDC) to the cable pair under test while measuring balance.
The high voltage stresses the conductors in order to reveal imbalances that
may otherwise be hidden with the normal VF/AC Balance test.
The test is very similar to the classic stress test well known in North
America. Compared to the VF (longitudinal) Balance test, values for the
Stressed Balance test are depicted as follows (but check your own
methods and procedures):
good 20 dBRNc
marginal = 20 to 30 dBRNc
bad > 30 dBRNc
In general, a pair that stresses 25 dBRNc is well balanced for POTS and
ADSL internet service. However, higher speed ADSL2+ and VDSL2 circuits
should stress 20. A low stress value (> 20) indicates imbalance on the
pair, which can have different causes. Most common causes are grounds
and shorts, but also one-sided series resistance (sometimes also called
high-open, high-resistive fault, or dirty open). Poor or failing splice
connectors/beanies also case minor imbalances affecting higher speed
DSL circuits.
Watch the stress level, and if you see an increase or jump after a minute or
two or more, the stress has worked through some corrosion and thus
revealed an imbalance. However, if the stress improves and you see a
lower value after a minute or two, then the stress voltage may have dried
up some moisture, thus hiding a wet/damp fault which will appear again
when more moisture works its way back into the fault.
When you have a poor stress value (> 25), the next best step is to isolate
the imbalance by running the Pair Detective test.
To Next Page
Loading...
