Hey, we are currently reviewing our Maintenance procedures on our switchgear and the requirements for ductor testing came up. Do you guys normally do ductor testing on your switchgear as part of the maintenance program? If so, how often? I read somewhere that some switchgear do not require ductor testing for the life of the eqt based on the manufacturer. Don't know how true that is. Any thoughts on this? The challenge I am facing is that the way our plant is set up, it is very difficult to get our switchgear de-energized while maintaining plant production. Even if we can overcome this challenge, the way the switchgear is made up and installed we will require alot of intrusive work to access the bus bars, which in my mind can do more harm than good. Any thoughts on this? Any advice wud be appreciated. Ductor testing is a requirement of NETA MTS as far as I see
Maintenance requirements for Switchgear - Ductor Testing
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zog
Senior Member
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- Charlotte, NC
I assume you are refering to bolted connections in the switchgear. NETA gives 3 options, "Ductor" tests, torque checks, or IR scanning.
Most do IR scanning, but that can be hard to get access to some parts of your gear, not to mention there are arc flash concerns. Get some IR windows installed, it will save money in the long run.
Thanks for the reply. I agree Infrared might be our best bet and this might be the opportunity to justify it.
Just to give some more background if any one else have any comments:
I was trying to get some information on the maintenance requirements for Cutler Hammer Switchgear, specifically when it comes to Ductor testing. We have Freedom 2100, Ampgard and the Metal Clad 15kV switchgear. My technicians are saying that performing ductor testing as a maintenance intervention is difficult because of the following:
-The switchgears are lined up back to back
-There is no access to all the bolted connections
-And we have to shut down the entire board which will affect plant production. Even in a shut down, we still have some loads running.
-Performing ductor testing will be intrusive and generally we feel that interferring with the connections could cause more harm than good
-Our switchgears are located in a controlled environment and are more or less steady state without temperature cycling cause the loads are constant
My question to you is, is ductor testing a requirement for Cutler Hammer switchgear - Ive read somewhere that some manufacturers do not require ductor testing for the life of the switchgear. But if it is, what would be the best way to go about doing ductor testing? NETA gives the option of ductor testing, torquing, or Infrared scanning. The same restrictions exist with Torquing and Infrared scanning is a risky task wrt arc flash. Im hoping you can provide some guidance on this.
Just to give some more background if any one else have any comments:
I was trying to get some information on the maintenance requirements for Cutler Hammer Switchgear, specifically when it comes to Ductor testing. We have Freedom 2100, Ampgard and the Metal Clad 15kV switchgear. My technicians are saying that performing ductor testing as a maintenance intervention is difficult because of the following:
-The switchgears are lined up back to back
-There is no access to all the bolted connections
-And we have to shut down the entire board which will affect plant production. Even in a shut down, we still have some loads running.
-Performing ductor testing will be intrusive and generally we feel that interferring with the connections could cause more harm than good
-Our switchgears are located in a controlled environment and are more or less steady state without temperature cycling cause the loads are constant
My question to you is, is ductor testing a requirement for Cutler Hammer switchgear - Ive read somewhere that some manufacturers do not require ductor testing for the life of the switchgear. But if it is, what would be the best way to go about doing ductor testing? NETA gives the option of ductor testing, torquing, or Infrared scanning. The same restrictions exist with Torquing and Infrared scanning is a risky task wrt arc flash. Im hoping you can provide some guidance on this.
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
Just checking, but I think ductor testing is contact resistance testing which is a test used to determine the condition of the contact pole assembly and its ability to carry current. If contacts are not maintained on a regular basis electrical resistance due to repeated arcing and/or corrosion increases, resulting in a significant decrease in the contact?s ability to carry current.
It has its place in a maintenace program, but not as often as IR scanning.
It has its place in a maintenace program, but not as often as IR scanning.
zog
Senior Member
- Location
- Charlotte, NC
I have never seen a manufacturer state this, I would like to know where you read that.
That is why many plants install IR windows, I think we installed close to 1,000 windows last year.
zog
Senior Member
- Location
- Charlotte, NC
That is just an article in a magazine, not a recognized standard or OEM recomendation.
ANSI/NETA recommends checking connections with 1 of the 3 methods I discussed. But there is no law saying you have to do anything. But consider this recent, could have been very very very bad example of not checking connections in switchgear.
http://pbadupws.nrc.gov/docs/ML1207/ML12072A128.pdf
From Root cause analysis-
"Specifically: (1) design reviews and work planning for a modification to install twelve new 480 Vac load center breakers failed to ensure that the cradle adapter assemblies had a
low-resistance connection with the switchgear bus bars by establishing a proper fit and requiring low resistance connections; (2) preventive maintenance activities were
inadequate to ensure proper cleaning of conductors, proper torquing of bolted conductorand bus bar connections, or adequate inspection for abnormal connection temperatures"
ANSI/NETA recommends checking connections with 1 of the 3 methods I discussed. But there is no law saying you have to do anything. But consider this recent, could have been very very very bad example of not checking connections in switchgear.
http://pbadupws.nrc.gov/docs/ML1207/ML12072A128.pdf
From Root cause analysis-
"Specifically: (1) design reviews and work planning for a modification to install twelve new 480 Vac load center breakers failed to ensure that the cradle adapter assemblies had a
low-resistance connection with the switchgear bus bars by establishing a proper fit and requiring low resistance connections; (2) preventive maintenance activities were
inadequate to ensure proper cleaning of conductors, proper torquing of bolted conductorand bus bar connections, or adequate inspection for abnormal connection temperatures"
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