How dangerous is a megger?

How dangerous is a megger?

Although Megger insulation testers are NOT inherently dangerous, safety officers and safety S.O.P.s often call for added diligence above 500 V. Time is an important test variable in insulation testing, much more so than in many familiar electrical tests.

Is megger testing destructive?

The Megger insulation tester is a small, portable instrument that gives you a direct reading of insulation resistance in ohms or megohms. This method is non- destructive; that is, it does not cause deterioration of the insulation.

What is a bad reading on a megger?

What is a bad reading on a Megger test? If the megger reads a resistance under 1 (1,000 ohms) on your meter after the initial 60-second interval, the cable has failed and the cable should be removed. If the megger reads a resistance between 1-1.25 on your meter, then the cable passes.

What happens when the human body is exposed to high voltage?

High voltage electrical energy greatly reduces the body’s resistance by quickly breaking down human skin. Once the skin is punctured, the lowered resistance results in massive current flow. At 1,000 volts, Current = Volts/Ohms = 1,000/500 = 2 Amps which can cause cardiac arrest and serious damage to internal organs.

Can you Megger a VFD?

DO NOT MEGGER ANYTHING CONNECTED TO A VFD!

Why do we do Megger test?

Megger testing measures resistance between the phase windings of the motor under test and ground. If there is an insulation breakdown, the resistance is negatively impacted and there is a departure between phases or between one measurement and a previous one and a determination of motor health is made.

Can you megger a VFD?

What is a bad insulation resistance reading?

The purpose of the IR test is to check for damaged insulation, this can be mechanical damage or damage by heat, (overloaded cables), readings less than 2 Mohm indicate damaged insulation, readings of 2-50 Mohm are indicative of long circuit lengths, moisture and contamination and do not indicate the insulation quality.

What is a good reading on a megger?

Anything reading between 2 megohms and 1000 megohms is usually considered a good reading, unless other problems have been noted. Anything less than 2 megohms indicates an insulation problem.

What is the maximum voltage a human can withstand?

Limiting current flow in the human body to safe levels is entirely dependent on the resistance of the short-circuiting jumper. To achieve this safe current level the voltage across the human body must not exceed 100 volts.

Which organ is mainly affected by electric shock?

An electric shock may directly cause death in three ways: paralysis of the breathing centre in the brain, paralysis of the heart, or ventricular fibrillation (uncontrolled, extremely rapid twitching of the heart muscle).

Can a megger damage a motor?

Any megger with a higher voltage output than 500 volts DC should be used by an experienced technician. A high voltage for too long of a time may further weaken or fail motor windings and the winding insulation could be damaged by the testing procedure.