Insulation Resistance Test Voltage

1. When D.C Volatge is used

Test Volatge (D.C) = 2 x Name Plate Voltage

2. Cable Rating and DC Test Voltage:

i. For 24 to 50 V ........ D.C Test Volatge 50 V to 100 V

ii. For 50 to 100 V ........D.C Test Volatge 100 V to 250 V

iii. For 100 to 240 V ........ D.C Test Volatge is 250 V to 500 V

iv. For 440 to 550 V ........ D.C Test Volatge 500 V to 1000 V

v. For 2400 V ........ D.C Test Volatge 1000 V to 2500 V

vi. For 4100 V ........ D.C Test Volatge 1000 V to 5000 V

3. Selection of IR Testers:

I.R testers are available in the ranges 500, 1000, 2500 and 5000 VDC.

i. For Volatge level of 650 V, IR Tester of 500 V DC

ii. For Volatge level of 1100 V, IR Tester of 1000 V DC

iii. For Volatge level of 3300 V, IR Tester of 2500 V DC

iv. For Volatge level of 66 kV and above , IR Tester of 5000 V DC

See:

http://www.nexans.us/eservice/US-en_US/fileLibrary/Download_540198890/

Actually it is very common to test any attribute at 150% to 200% of the attribute rating. The important thing is that the device producing the over rating attribute is designed to not destroy the device under test should it fail the test. Testing the insulation of a 750V cable at 1000V with an insulation testing instrument is normal. Trying to perform the same test using a 1000V power distribution connection for the source is foolish if not negligent.

Make it simple

200% of rated operating voltage.

As for acceptable values I still stick to the old UK M&Q value of 1/10,000^th FLC

G.A. operational voltage is the deciding factor.

Is that mean if I am using a 450/750V rated cable for 415V 3-phase system, test voltage 415 x 2 = 930V. So 1000V test voltage to be selected, not the 500V which is allowable voltage for cable ? I hope you all dont mind if I always turn around this topic. I just want to clarify all possibilities.

It depends on the electrical test standard you are working to (they vary from country to country and between equipment, site wiring, etc). There is no single right answer and 1000V may be to low.

Do you know what test standard you are supposed to be working to for the wiring you are trying to test in the application it is intended to be used in the country it is to be used in?

Standards? Standards? We don't need no stinking standards. We just make up our own rules like any bandit. You stupid gringos think you can come here and tell me how to fleece a customer by using a standard. If I used a standard they might learn something. Then they won't come back to me. Besides I got my answer from a French model I met on the internet.

In our area, contract specification usually specify 600/1000V rating for submain cable. But all the suppliers here are selling 450/750V rating material. For a consultant, they are looking for insulation test using 1000V. Is there technical compliance explaination that we can convince the consultant that using 500V for testing the submain cable rated at 450/750V actually giving the same result as using 1000V test voltage. This has been normal using 450/750V rated cable for submain here, only some consultant not aware.

If the consultant would accept a 1000V test to allow you to supply the lower voltage cable then just test it and send them the test results/report. I would be very surprised if the 450/750V cable fails a simple 1000V insulation test.

The mains-rated power cable should be more than capable of handling this voltage because cable suppliers over-rate the cables to allow them to handle high voltage impulses, spikes, etc that they will undoubtedly see when installed in the real world power network.

hi, It's not wrong, Because 450/750V cable is rated with 1.1KV Grade, so you can test IR Values with 1000V IR Tester.