Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


SF6 breaker maintenance

SF6 breaker maintenance

SF6 breaker maintenance

the OEM's manual of the SF6 breaker in question is quite sketchy - we were trying to contact somebody that would give more info but ran into a deadend because the SF6 breaker is not in their product line anymore.

i googled for info but cannot decide what is good or not...

would you guys be so kind to point me to a good source for SF6 breaker maintenance practices, requirements, routine and long term maintenance program, etc.

thank you in advance.


RE: SF6 breaker maintenance

The NETA Acceptance and Maintenance test procedures would be a good start.


RE: SF6 breaker maintenance


DanDel gives good advice.  You should be able to find the manufacturer instruction books for your breaker.  If not, post a note with the model number, somebody here's bound to have information.

Like any other breaker, you want to check insulation, all poles to ground and to each other, isolation across open contacts, speed of operation, contact resistance, electrical and mechanical integrity of control and actuation mechanisms, and proper function in relation to its control circuit.

The details to accomplish each of each of these items  varies from manufacturer to manufacturer.  Teh frequency at which you perform this work varies also with the installation environment and severity of service.

I would recommend that you consult any NETA company for advice, since the testing involved will require specialized equipment and knowledge.

old field guy

RE: SF6 breaker maintenance

Who is the manufacturer and what is the type

RE: SF6 breaker maintenance

G & W Electric manufacture these types of breakers and could point you in the right direction.  They offer field services as well.  Especially if it is their equipment.  Contact them at www.gwelec.com They can give you the name of a rep in your area. I am assuming you are in the US, but they probably have international branches as well.

Buena Suerte

RE: SF6 breaker maintenance

I agree with the above and as a former field guy have my 2 cents.

Annually, you should take an SF6 sample.  This is a relatively easy procedure.  The sampling kits are available from various laboratories.  The samples should test for moisture and dielectric strength of the gas.

The low pressure alarms / cuts out circuits should be verified for proper operation.

Timing / time travel should be performed.

A contact resistance test should be performed and compared to manufactures published data.

The mechanism should be lubricated and exercised.

Depending on your climate, the SF6 heaters / thermostat should be inspected and verified for proper opertion.

SF6 breakers are relitively maintenace free, however that does not mean maintenance should be ignored.

As a formed service rep for a HV breaker manufacturer, I can assure you that megger or doble type tests will fail to yield any significant results (other than good) for an SF6 breaker.  The gas is the major insulation and will reveal any incipient insulation problems.  The bushings are not the same type as those found in transformers (condenser type) and will not have a Power Factor test tap.  They are hollow inside, filled with SF6 from the breaker main tanks.

Be sure to inspect your battery system and at least trip the breaker from all associated protective relays at the same maintenance outage.

Hope this helps.

RE: SF6 breaker maintenance


You're absolutely dead on.  I had much fun doing power factor tests of SF6 breakers and they were universally "good".  We still did the tests at the client's request because those were the tests he did on all his OTHER breakers.

After a career of fighting with the huge and heavy mechanisms of HV oil circuit breakers, SF6 is a godsend.

old field guy

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close