Chart boundary

Does not set a pass/fail value, approve energization, replace manufacturer instructions, or define a commissioning procedure.

planning map

Test-voltage selection bands

Use the bands to choose the next reference source; use the linked table only when a lookup row is needed.

Scopegrounding and testingX-axistest planning sequenceY-axisequipment sensitivityReviewAnnualNextInsulation Resistance Test Voltage Source Navigation
Test-voltage selection bandstest planning sequenceequipment sensitivity1Equipment classcontrols / feeder...2Voltage bandnameplate first3Isolation checkelectronics / SPD...4Record conditiontemperature / hum...Planidentify circuitIsolateprotect electronicsSelecttest-voltage referenceRecordconditions and result
Use the bands to choose the next reference source; use the linked table only when a lookup row is needed.
1
Equipment classcontrols / feeder / motor / cable

Different equipment drives different test planning.

2
Voltage bandnameplate first

Nominal voltage points to the lookup table or manual.

3
Isolation checkelectronics / SPD / loads

Sensitive devices may need disconnection before testing.

4
Record conditiontemperature / humidity / history

Interpretation depends on test conditions and trend records.

Planidentify circuit

Confirm what is connected.

Isolateprotect electronics

Remove sensitive connected equipment where required.

Selecttest-voltage reference

Use manufacturer or table guidance.

Recordconditions and result

Do not judge pass/fail from this chart.

Decision reference

Show the source-selection questions to resolve before using the insulation resistance test-voltage table or manufacturer instructions.

Reference basis: Fluke insulation testing references and Megger insulation resistance tester technical guidance.
MethodBest fitWatch pointHandoff
Control circuitsLow-energy equipment reviewSensitive electronics and connected devicesManufacturer instructions
Low-voltage power circuitsFeeder or equipment insulation screeningConnected loads and surge devicesTest-voltage table
MotorsWinding insulation trendingTemperature correction and historyMotor test procedure
CablesInstalled cable insulation screeningCable type and termination conditionCable manufacturer data

Use notes

  • Use this chart as a planning and conversation aid only.
  • Confirm current utility requirements, product markings, manufacturer instructions, and local authority requirements before field work.
  • Use the linked calculator or table when the task needs project-specific arithmetic.

Reference sources

Open the underlying public references before treating the chart as project guidance.