×
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

Wire sizing for emergency generator

Wire sizing for emergency generator

Wire sizing for emergency generator

(OP)
I need help with sizing the electrical feeder from the emergency generator to the automatic transfer switch. It is for a 50KW 208V/3PH, 0.8 pf, natural gas unit. The cut sheet says 173 amps Standby and 139 amps Prime. What amperage do i size it for?

Thanks

RE: Wire sizing for emergency generator

See NEC Article 445. Basically, at least 115% of generator nameplate current rating.

RE: Wire sizing for emergency generator

And it may well be that neither of those numbers are the nameplate rating.

RE: Wire sizing for emergency generator

Hire an electrician. Save a smoke.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Wire sizing for emergency generator

As the rated power is 50 kw the rated current will be 173.5 A [more or less as Stand-by].As dpc said [see NEC 445.13 ] the conductor has
to be suitable for 173.5*1.15=200 A.Now, it is not so simple since art.445.15 will send you to 220.61 and 250.30(A).
But in order to find the type and cross-section of the required cable you need other articles-and may be some other calculation. So waross
advice it seems to me suitable also.

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