What methods do you use for corona suppression when testing cable?

[madMAX]

This may be going overboard but for the test end I like to tape my lead to the conductor with some rubber splicing tape, wrap that with 33, and wrap all of that with plastic wrap. Opposite ends will usually just get plastic wrap and a PVC boot (made from piece of 18" PVC pipe and cap). With this method I get no hissing even with high humidity. Anyone have similar methods to suppress corona when testing cable?

[randywright]

Splice tape is usually good enough unless you are testing at crazy high voltages. Rubber safety blankets are also very useful when testing cable.

[AlexV86]

depending on test set our VLF/TD units minus the TD28 have corona Balls otherwise its wrap the lug tightly in the thicker Danger Tape and a little electrical tape to hold it in place then toss a rubber insulating boot over that does a good job but is not perfect, also less expensive then using splicing tape.

[madMAX]

Corona Balls? Sounds like you got that fancy stuff, Alex. My company only provides the bare essentials. Using rubber boots and blankets seems like a good idea except large blankets can be a pain to work with. Maybe I can rob some boots if I come across some on a job. The insulating plastic I have is only good for 8kV I think.

[alexlounsbury]

During VLF testing, I haven't found a need to cover the cables. The theory behind the practice is just to limit the amount of air moving across the cables.

For DC HiPot, keep in mind it's a pass/fail test. I used to work hard for high quality corona supression, but even a high reading shouldn't be used for trending. If it holds the voltage, it passes. Leakage currents will vary widely with humidity and wind, regardless of the supression method. Also worth noting that any direct contact that the insulation method makes will create a point for leakage current.

In a pinch several years ago, I used latex gloves. They worked great, though I wouldn't recommend them as a general practice.

[Chipperk]

This may be going overboard but for the test end I like to tape my lead to the conductor with some rubber splicing tape, wrap that with 33, and wrap all of that with plastic wrap. Opposite ends will usually just get plastic wrap and a PVC boot (made from piece of 18" PVC pipe and cap). With this method I get no hissing even with high humidity. Anyone have similar methods to suppress corona when testing cable?

I use elastimold fixtures on load break and dead break elbows look on eBay. Zero corona! They are not cheap but makes your job so much easier in high humidity areas with allot of wind and such. I also use the splicing tape on air connections.

[chils15]

Man scotch 33 bet the boss didn't put that in his price. Just use the danger tape works good

[copes2680]

130C tape and a good boot and your good to go. Unless you have corona balls

[whiskers]

This may be going overboard but for the test end I like to tape my lead to the conductor with some rubber splicing tape, wrap that with 33, and wrap all of that with plastic wrap. Opposite ends will usually just get plastic wrap and a PVC boot (made from piece of 18" PVC pipe and cap). With this method I get no hissing even with high humidity. Anyone have similar methods to suppress corona when testing cable?

What works for me are corona balls. Not the expensive ones. Just go to a craft store and buy a bunch of those Styrofoam balls of different sizes and bring along a roll of aluminum foil.

Wrap the ball in the foil and just jam it on the end of the cable. Works every time.

[SecondGen]

What works for me are corona balls. Not the expensive ones. Just go to a craft store and buy a bunch of those Styrofoam balls of different sizes and bring along a roll of aluminum foil.

Wrap the ball in the foil and just jam it on the end of the cable. Works every time.

Great tip, I will be trying this next time I test cable.

[whiskers]

Great tip, I will be trying this next time I test cable.

When wrapping the ball, you may want to adjusts the length of the foil to wrap around the cable center a little bit and secure it with a rubber band. This way you are sure the foil is in contact with the center conductor.

[SecondGen]

When wrapping the ball, you may want to adjusts the length of the foil to wrap around the cable center a little bit and secure it with a rubber band. This way you are sure the foil is in contact with the center conductor.

Thanks, I was wondering about the best way to make uniform contact. The rubber band idea is good, I'm thinking it would also be good to jam the foam on the cable first and then wrap so you can stuff the foil way down in the hole.

Another thought would be to make some up with various size holes or just put extra wraps on the cable until it fits. Next cable job will double as arts and crafts day.

[TrapFlyVenus]

What works for me are corona balls. Not the expensive ones. Just go to a craft store and buy a bunch of those Styrofoam balls of different sizes and bring along a roll of aluminum foil.

Wrap the ball in the foil and just jam it on the end of the cable. Works every time.

Where do you place lead once you add the styrofoam balls

[whiskers]

Where do you place lead once you add the styrofoam balls

Prior to adding the Styrofoam balls, I use a small piece of hipot wire and twist it tight on the inner conductor right at the beginning of the rubber insulation, then place the ball on to the wire.

Hope that helps.

Bill

[Ronwilson1801]

Corona Balls? Sounds like you got that fancy stuff, Alex. My company only provides the bare essentials. Using rubber boots and blankets seems like a good idea except large blankets can be a pain to work with. Maybe I can rob some boots if I come across some on a job. The insulating plastic I have is only good for 8kV I think.

We do the same thing.

[gbriske]

What works for me are corona balls. Not the expensive ones. Just go to a craft store and buy a bunch of those Styrofoam balls of different sizes and bring along a roll of aluminum foil.

Wrap the ball in the foil and just jam it on the end of the cable. Works every time.

Wow I've never thought of this, a couple of our sets don't have the corona balls but I will be adding some of these for future cable tests thanks for the tip!

[B_king53]

Yea, I have made something very similar and it works quite well. If they are unavailable or I have need of more I have used old high voltage gloves and taped those as well.


This may be going overboard but for the test end I like to tape my lead to the conductor with some rubber splicing tape, wrap that with 33, and wrap all of that with plastic wrap. Opposite ends will usually just get plastic wrap and a PVC boot (made from piece of 18" PVC pipe and cap). With this method I get no hissing even with high humidity. Anyone have similar methods to suppress corona when testing cable?