The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.
Insulation resistance test results table.
For good insulation the resistance usually reads in the megohm range.
Short time or spot reading test.
A rated line to line voltage for three phase ac machines line to ground voltage for single phase machines and rated direct voltage for dc machines or field windings.
Higher voltages are used to stress an insulation to a greater degree and thus obtain more accurate results.
B kv is the rated machine terminal to terminal voltage.
For low voltage installations i e.
The international electrical testing association neta specification maintenance testing specifications for electrical power distribution equipment and.
With a little record keeping and common sense however you can get a good picture of the insulation condition from values that are only relative.
Ansi neta mts 2015 table 100 11 insulation resistance test values rotating machinery for one minute at 40 c.
Insulation resistance test results are dependant on a number of factors such as temperature and humidity.
Helps to plan for the future with respect to funding for.
Insulation resistance decreases in temperature or moisture.
Do not touch or move conductor during testing as results will be affected.
Historically many field electricians use the somewhat arbitrary standard of 1 megohm per kv.
Insulation resistance testing path can affect the test and reduce the insulation resistance reading.
230v to measure insulation resistance in ohm s.
Recommended test voltages for routine maintenance insulation resistance tests of equipment rated to 4 160v and above.
The megger insulation tester is a small portable instrument that gives you a direct reading of insulation resistance in ohms or megohms.
The insulation resistance test is an electrical test which uses a certain type and level of voltage 500v d c.
Do not allow the leads to touch during the test.
As a production test this test is often used as a customer acceptance test with minimum insulation resistance per unit length often specified by the customer.
Why perform insulation resistance testing it s the law 33 cfr 208 10 f 1 megger tests of all insulation shall be made whenever wiring has been subjected to undue dampness and otherwise at intervals not to exceed one year.
Values based on ieee std 43 2013.
Minimum acceptable insulation resistance for 600 v cable from 100 to 1000 feet.
The measurement of insulation resistance is a common routine test performed on all types of electrical wires and cables.
A record shall be kept showing the results of such tests.
Suspend and isolate the test set leads in air as much as possible.
The most common voltages are 500v and 1 000v.
However let s talk now about three basic types of insulation resistance tests using megger tester.
Also acceptable values of insulation resistance depend upon the equipment you re testing.
