Insulation Testing 20kV Ignition Wire

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MrJLH

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I will likely need to pull new ignition wire to the top of a flare as part of a ignition assembly replacement. I'm looking for some guidance on insulation testing the ignition wire. Wire will be a single conductor 18AWG, 20kV rated, with MICA insulation.

I'm typically used to testing 600V wire at 1000V per NETA, but I'm a little lost on this one.

Thanks
 
MrJLH said:
I will likely need to pull new ignition wire to the top of a flare as part of a ignition assembly replacement. I'm looking for some guidance on insulation testing the ignition wire. Wire will be a single conductor 18AWG, 20kV rated, with MICA insulation.

I'm typically used to testing 600V wire at 1000V per NETA, but I'm a little lost on this one.

Thanks
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IMO testing new wire like this serves no real purpose. The manufacturer tested it and they can do a better job at it than you can.

I would be doing a visual inspection when it comes in to make sure there is no obvious damage in shipping and then install it and turn it on.
 
petersonra said:
IMO testing new wire like this serves no real purpose. The manufacturer tested it and they can do a better job at it than you can.

I would be doing a visual inspection when it comes in to make sure there is no obvious damage in shipping and then install it and turn it on.
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Wouldn't the purpose be establishing a baseline to compare future readings to?
 
petersonra said:
Its a few feet of wire. It is not worth the time to test it. If it has issues, you just replace it.
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I was under the impression it was a long wire with a significant portion inaccessible (top of flare?) but I agree, if it's short and accessible inspection is fine.
 
220203-1916 EST

When one does an Internet search on insulation breakdown voltage of air the results are very poor. Some places you will find 3 kV/mm with no other information. Electrode shape makes a big difference, as does pressure, and presence of radioactivity.

When you look at other dielectric materials the results are just as bad.

Many dielectric materials like polyethylene may have a rating of 1000 V/mil in thin sections. But when that material is thicker this rating drops considerably. However, if you use many thin layers on top of each other, then the rating goes up toward the thin layer rating. Beyond considering where materials breakdown one wants to operate at much lower voltage levels, safety factor.

The electric field level is what determines voltage breakdown level. My guess is that if you took RG8 coax, stripped the shield off, and did not lay it on a conductor that you would be good for 100,000 V.

.
 
petersonra said:
Its a few feet of wire. It is not worth the time to test it. If it has issues, you just replace it.
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Actually, the run is about 600ft from the control panel to the tip of the flare. My site standards also clearly dictate that all cable be tested before putting into service.
 
MrJLH said:
Actually, the run is about 600ft from the control panel to the tip of the flare. My site standards also clearly dictate that all cable be tested before putting into service.
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I do not have any calculations to back this up, but I would be concerned about the effect of the wire capacitance on the igniter voltage over that long a distance.
Transformer driven would probably not notice, but piezo-electric voltage source might be adversely affected.
Probably a non-issue since this is replacement wire in an existing installation.
 
MrJLH said:
I will likely need to pull new ignition wire to the top of a flare as part of a ignition assembly replacement. I'm looking for some guidance on insulation testing the ignition wire. Wire will be a single conductor 18AWG, 20kV rated, with MICA insulation.
Click to expand...

MrJLH said:
Actually, the run is about 600ft from the control panel to the tip of the flare. My site standards also clearly dictate that all cable be tested before putting into service.
Click to expand...

Technically, a cable is comprised of multiple wires. So the question is whether your site standards would require testing of an individual wire. Also, voltage testing of a single wire on a spool is kind of meaningless, because there will be no voltage gradient between the turns. Also, what would be the voltage reference since you would have to apply a test voltage between two points?

If you choose to unspool the wire for testing, then you would have to place it some uniform distance from another conductor along the entire length to establish a controlled voltage gradient level across the insulation. It just doesn't sound very practical for your situation.
 
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