Isolation Resistance and Insulation Resistance

message: what is insulation and isolation resistance, why and how it is measured? what are the consequences if it is not measured? 2008

Isolation Resistance and Insulation Resistance are both related to each other. Isolation Resistance could be in Giga Ohms and Tera Ohms and includes Surface Resistivity.

Insulation Resistance will be in the Range of Mega Ohms and Giga Ohms. You could say Isolation Resistance is a Tera Ohm and Giga Ohm Measurement Test.

Let us assume a 5KV Isolation Opto-Coupler on a Glass Epoxy PCB. You could Measure its Isolation or Insulation Resistance and it will be in the range of 1 Tera Ohms in a good PCB.

A good PCB will have a Slot Routed below the Opto Coupler for High Isolation. This will ensure Dust and Grime along with Moisture will not form a Leakage path below opto-coupler.

Use a Megohmmeter for Insulation Resistance of Transformers, Coils and Relays. Use a Teraohm Meter to measure Isolation Resistance in Opto Couplers, PCB, Ceramics and Capacitors.

Megohmmeter is a special type of ohmmeter used to measure the electrical resistance of insulators. Insulating components, for example cable jackets, must be tested for their insulation strength at the time of commissioning and as part of maintenance of high voltage electrical equipment and installations.

6520 Programmable Teraohmmeter makes resistance measurements up to 10 PΩ. Whether used in automated mode via the Guildline developed TeraCal Software or as a stand-alone meter,