INSULATION RESISTANCE READINGS
Normal Ohm and Megohm Values between all leads and ground
Condition of Motor and Leads
A new motor (without drop cable).
A used motor which can be reinstalled in well.
Motor in well. Readings are for drop cable plus motor.
New motor.
Motor in good condition.
Insulation damage, locate and repair.
Insulation resistance varies very little with rating. Motors of all HP, voltage and phase ratings have similar values
of insulation resistance.
Insulation resistance values above are based on readings taken with a megohmmeter with a 500V DC output.
Readings may vary using a lower voltage ohmmeter, consult factory if readings are in question.
TYPICAL INSTALLATIONS
TETHER
LENGTH
CHECK VALVE
VENT
ON
OFF
Drawing 1
20,000,000 (or more)
10,000,000 (or more)
2,000,000 (or more)
500,000 - 2,000,000
VENT
GATE VALVE
INFLUENT
BASIN
Ohm Value
Less than 500,000
DISCHARGE
PIPING WITH
UNION AND
CHECK VALVE
Drawing 2
Megohm Value
20 (or more)
10 (or more)
2 (or more)
.5 - 2
Less than .5
INLET PIPING
WITH UNION
AND TRAP
9