Megger question.
- Thread starter Saywatt
- Start date
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SG-1
Senior Member
- Location
- Ware Shoals, South Carolina
I frequently do dielectric tests on switchgear control wiring. Many of them have standard 120V recepts & light switches. The test voltage is 1500V AC RMS for 1 min. I have never had one fail. If they have any electronics in them like a GFI, then disconnect it. To help make sure everything is shorted together close all the switches.
ohmhead
Senior Member
- Location
- ORLANDO FLA
Our megging is wire gear tranformers buss duct busses everything never had a issue you disconnect the electronic breakers and controls you megg it pull out the fuse blocks in the gear it helps with the electronic breakers kinda .
We megg with breakers off in switch gear we megg the feeders before we terminate them to breakers we must record each megg reading .
If ya megg thur breakers you get strange readings sometimes not a good test .
We dont megg a vfd or drives and such we dont megg thur breakers thats another test which is a low ohm test on contacts and such but megging is safe on just about any insulation test it really cant hurt at 1000 volts .
zog
Senior Member
- Location
- Charlotte, NC
You are always supposed to isolate what you are testing
ptonsparky
Tom
- Occupation
- EC - retired
- Location
- Illinois
- Occupation
- retired electrician
There is no issue with using a megger on a receptacle circuit with the receptacles installed. The only issue would be if you have cords plugged into the receptacles when doing the testing. The UL standard for receptacles requires that devices rated at 300 volts or less pass a 2000 volt dielectric withstand test for one minute.
ptonsparky
Tom
- Occupation
- EC - retired
Should have put a :roll: or two above
Most (all?) is rated at 600 Volts. The utilization voltage can be 120, 208, 480etc.
- Location
- Massachusetts
Many common devices are not rated over 125 or 250 volts.
Think switches, breakers, receptacles etc.
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