megger testing

[rodrpr54]

We are running a test on a large alternator with a portable hi-pot which is outputing 5000 voltsDC. We are also spraying water on the coils looking for problems with the insulation. We have our PPE on.

Is there anything in the NEC or Osha that requires that there be two men to perform this test?

 

[RHaggie]

OSHA requires that a person exposed to hazards be trained on the specific hazards, not that two people are present when squirting water at 5kV DC.

 

[realolman]

I think there's something in there that says I ain't allowed to do it.:smile:

I don't have an answer to your question, but I would be interested if you would elaborate exactly how and why you are doing this.

 

[Ken9876]

I don't know much about megging equipment, but there are better ways to test the insulation of the windings, There are two tests that can be done longer one to test for moisture and another for the insulation. I'll have to find the book where I read this

 

[zog]

1st of all, there are much better ways to test those windings, not sure where you found that testing procedure. PI, DAR, and MCE testing is more common.

2nd, to answer your question:

1910.269(l)(1)(i) Except as provided in paragraph (l)(1)(ii) of this section, at least two employees shall be present while the following types of work are being performed:

(l)(1)(i)(A) Installation, removal, or repair of lines that are energized at more than 600 volts,

(l)(1)(i)(B) Installation, removal, or repair of deenergized lines if an employee is exposed to contact with other parts energized at more than 600 volts,

(l)(1)(i)(C) Installation, removal, or repair of equipment, such as transformers, capacitors, and regulators, if an employee is exposed to contact with parts energized at more than 600 volts,

(l)(1)(i)(D) Work involving the use of mechanical equipment, other than insulated aerial lifts, near parts energized at more than 600 volts, and

(l)(1)(i)(E) Other work that exposes an employee to electrical hazards greater than or equal to those posed by operations that are specifically listed in paragraphs (l)(1)(i)(A) through (l)(1)(i)(D) of this section.

 

[RHaggie]

zog,
Your answer implies that using the hi-pot requires two people since the equpment is energized above 600V by the tester.

Is that right?

 

[zog]

Yes. I actually wrote a letter to OSHA for clarification on this. I asked "My question is: When conducting insulation resistance testing on a 480V bus run with a test voltage of 1000VDC, could this work be conducted alone, or would a second (qualified) person be required?"

Thier reply was: "The answer to your question would be yes 2 qualified people need to be present anytime an employee is exposed to 600 volts or greater. Since you are running a test of 1000 volts which exceeds 600 that would place you into paragraph (E) highlighted above for the task that you are performing and A-E covers the voltage"