How to Test Breakers ep2: Medium Voltage Vacuum Circuit Breaker

In this video I run through all the required NETA MTS tests to perform maintenance on a 5kV Medium Voltage Vacuum Circuit Breaker.
0:00 Intro
3:32 Visual and Mechanical Inspection
7:42 Manual Operation
8:22 Electrical Operation
10:28 Contact Timing Test
15:10 Insulation Resistance Tests
17:01 Contact Resistance Tests
19:10 E-Gap (Contact Wear Measurement)
20:45 Vacuum Integrity (Hi-Pot/Overpotential)
28:54 Lubrication and Final Thoughts
Background music from: freelofi.com

[@smadusnk]

Quality stuff.Thankyou very much 🎉

[@testingtechtips]

Glad you enjoyed it

[@BurRun-kt3tf]

Thanks អរគុណ❤

[@southernstaffing]

Thorough, but easy to follow! Thanks for sharing!!!

[@testingtechtips]

Happy to share!

[@bspdm4954]

Dude, thank you for these videos....and please keep them coming. Please perform standard NETA MTS testing on a medium voltage contactor, including gap and wipe measurements. :)

[@testingtechtips]

Great suggestion! To make these longer form videos I need to have everything in a convenient place like the shop at the same time but I will try to make that happen.

[@khalidjxbify]

Very informative and easy to follow video. Expecting to test a MV breaker very soon. Please make more videos. As always, you are a wealth of knowledge !!

[@testingtechtips]

Thanks! I've got more videos on the way!

[@soe2152]

Great content again. Really enjoy it, thanks for sharing your knowledge. Waiting on new Relay series...

[@testingtechtips]

More to come!

[@SB-dc9qb]

Excellent video! Thank you

[@testingtechtips]

Glad you liked it!

[@gerardwalsh6215]

Great video 👍

[@testingtechtips]

Thanks 👍

[@nickvalle1852]

Would be really nice to see how to test Ground fault on the breakers

[@testingtechtips]

Medium voltage breakers like this don't have protection built in; they'll use an external relay for overcurrent, ground fault, or anything else. I'm actually working on a series of relay testing videos right now so stay subscribed!

[@craytonzaragoza3479]

good stuff, could you show more on how to hook up the leads

[@testingtechtips]

Which leads in particular?

[@freepalestine9685]

Great Job and it is nice work..... but I have a comment, I think when you do the Hipot Test you have Two ways to test it first one is by closing the CB and taking every single phase with earthing another phase. the second way is by opening CB and shortening the top boles and applying High voltage by earthing the below Boles. if you see something that I cannot see tell me Please and thank you for this information

[@testingtechtips]

I'm following the NETA MTS standard for this video. The only hi-pot/dielectric withstand test required for this type of breaker is the "vacuum bottle integrity" test which is primarily ensuring the contacts are effectively open. The DC insulation resistance(megger) tests verify everything else is good.

[@wyattredding5529]

I use a HVI VLF-65E test set would you have settings on a VLF system? It has only a hot test lead and ground.

[@testingtechtips]

I'm sorry, but I don't understand your question. You can definitely use a VLF to test the vacuum bottles

[@jessewilliamson728]

I like what you're trying to do with simplifying the hipot test and it does work for bottle integrity but it would not be an acceptable test for phase to phase or phase to ground as your method never actually energizes the load side of each phase. Standard practice from what I have learned is breaker open applying voltage line to load for each phase in guard mode for bottle integrity, then breaker closed applying voltage to line/load of one phase in ground mode with other phases shorted together and to frame, ground lead stays on frame the whole time, return lead is on load side for open pole and shorted phases for closed pole tests. Make sense?

[@toastymotors]

Thanks for your question. If the leakage current from line to load and ground is less than the max allowable leakage current across the bottle (if spec'd out) then the current exclusively from line to load is going to be less than that. This meets the NETA spec for the vacuum bottle integrity test. There is no NETA requirement to hi-pot phase-to-phase, and I've not seen a recommendation to perform that from any OEMs, though you should always check the manual first! We are required to perform DC insulation resistance (megger) tests phase-ground and phase-phase which I cover earlier in the video.

[@jessewilliamson728]

@@toastymotors There may not be a NETA requirement for phase to phase testing as the standards do defer to manufacturer's published data for dielectric withstand but with your testing method are you not also automatically including phase to phase testing by shorting all other phases to ground/frame? Back to the main point of my original comment, dielectric withstand would still have to include line and load of each phase to ground correct? With the method demonstrated you are not applying voltage to the load side of any phase with the hipot, effectively missing half of a normally energized insulation system per phase in your measurement. Enjoying the videos by the way.

[@testingtechtips]

Again, the only hi-pot/dielectric withstand test required by NETA is the vacuum bottle integrity test, so what I showed meets the requirement. I totally agree though, there's more that you MAY need to do. I know for like pole-mount reclosers the OEMs will spec out line->load and load->line tests but to the best of my knowledge that isn't required for any draw-out MV breaker.