1817
Locating High Resistance Connections
Troubleshooting to identify the cause of the high impedance within the elec-
trical system is actually quite simple. First measure the voltage drop at the
furthest receptacle from the panel on the branch circuit under test. If the
voltage drop is high, than further investigation is necessary.
Testing the remaining receptacles in sequence, from next furthest from the
panel to the closest to the panel, will identify the problem.
If the voltage drop reading changes significantly from one receptacle to the
next, then the problem is a high impedance point at or between the two
receptacles. It is usually located at a termination point, such as a bad splice
or loose wire connection, but it might also be a bad receptacle.
If the reading steadily decreases as you get closer to the panel, with no sig-
nificant decreases between receptacles, then the wire may be undersized for
the length of run, or for the load on the line. Check at the panel to see if the
wire is sized per code, and measure the current on the branch circuit.
The reading may not decrease at all from the last receptacle to the first. This
would indicate that the problem could be at the first splice, or at the panel
itself. Most poor panel connections show up as hot spots on the panel.
These can be checked quickly with an infrared temperature meter.
Quick Reference Guide Measurement Menu
Line Voltage Menu
Press → Press→ Press→
Line Voltage for next Peak Voltage for next Frequency for first
Measurement test Measurement test Measurement test
Press
↓
to advance to Voltage Drop Menu
V
oltage Drop Menu
Voltage Drop Press → Voltage Drop Press → Voltage Drop Press →
Measurement for next Measurement for next Measurement for first
@ 15-Amp test @ 12-Amp test @ 20-Amp test
Press
↓
to advance to Ground-Neutral Voltage Menu
Gr
ound-Neutral Voltage Menu
Ground-
Neutral
Voltage
Measurement
Press
↓
to advance to Line Impedance Menu
Line Impedance Menu
Neutral
Hot Conductor Press
→ Conductor Press → Ground Press →
Impedance for next Impedance for next Impedance for first
Measurement test Measurement test Measurement test
Press
↓
to advance to Line Voltage menu
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