Ideal SureTest 61-164 Manual De Instrucciones página 7

Impedance (Z) Measurements
If the voltage drop measurement exceeds 5%, analyze the hot and neutral impedances. If one is
significantly higher than the other, the problem is with the conductor with the much higher imped-
ance. Then, check all connections on that conductor back to the panel. If both impedances appear
high, the source can be undersized wire for the length of run, a bad device, or poor connections at
the pigtails, devices, or panel.
The ground impedance measured should be less than 1 ohm as a rule of thumb to ensure that
fault current has a sufficient path back to the panel. IEEE states the ground impedance should be
less than 0.25 ohms to ensure the ground conductor can safely return any fault current which
could damage equipment on the circuit. Surge suppression systems require a good ground to
adequately protect equipment from transient overvoltages. Note that a current is applied to the
ground conductor to accurately measure its impedance. By the inherent nature of this test, a GFCI
protected circuit will trip unless the device is temporarily removed from the circuit. Due to the
ground impedance test inducing current on the ground conductor, this tester must not be used in
active paitent care areas or in situations where people may be connected through devices to the
electrical grounding system such as ESD strap protection or medical equipment.
Troubleshooting Tips - Impedances
Measurement
of 14 AWG wire
Hot and Neutral
of 12 AWG wire
Impedance
or 10 AWG wire
Ground Impedance
GFCI Testing
To test the GFCI device, the SureTest
tors by leaking a small amount of current from hot to ground using a fixed value resistor. The test
current applied by the SureTest
A functional GFCI should sense the imbalance and disconnect the power. The SureTest displays
the actual test current in milliamps and trip time in milliseconds.
Expected
Result
<0.0048Ω/foot
<0.003Ω/ foot
High conductor
impedance
<0.001Ω/ foot
< 1 Ω to
protect people
<0.25Ω to
protect
High ground
equipment
impedance
®
should not be less than 6mA or greater than 9mA per UL-1436.
®
Problem Possible
Too much load
on branch circuit.
Undersized wire
for length of run.
High resistance
connection within the
circuit or at the panel.
Undersized wire
for length of run.
High resistance
connection within
the circuit or at
creates an imbalance between the hot and neutral conduc-
7
Causes
Redistribute the load
Check code requirements
and rewire if necessary.
Locate high resistance
Check code requirements
and re-wire if necessary.
Locate high resistance
the panel.
Possible
Solutions
on the circuit.
connection/device
and repair/replace.
connection/device
and repair/replace.