×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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

Jobs

Breaker ratings?

Breaker ratings?

Breaker ratings?

(OP)
I've seen more than one client's standard requiring 22kAIC breakers on all 208Y/120V systems. 10k breakers are unacceptable. When asked why - I've always heard "That's the way we've always done it," or "It's our standard." Is there a good reason (or any reason) for this requirement?

Thanks

RE: Breaker ratings?

One reason might be to allow future increases in transformer size without replacing the breakers.  You might get by with 10 kA breakers with a 5% impedance 150 kVA transformer.  If the load increased in the future to require a 300 kVA transformer, you would be in trouble.

RE: Breaker ratings?

Plan carefully though. 22kAIC breakers are expensive compared to 10k.

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!


Resources