Previous in Forum: Grand Father Clock   Next in Forum: Sacrificial Anode Required by Client for Pipes Coated With Phenolic Epoxy
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
13 comments
Rate Comments: Nested
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11

Selection of Power Cables

01/08/2012 1:47 AM

Could anyone give me information on how you select a wire for a certain currents or voltage according to the code and standards? I am having this problem of hvac equipment on where Ican find the proper size of a cable in according to standard. Please help, more power guys. Good Luck
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
3
lyn
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#1

Re: Selection of Power Cables

01/08/2012 2:10 AM

Google, "wire size calculator".

This question gets asked every day.
Register to Reply Good Answer (Score 3)
No more Good Answers. Go to first "Almost" Good Answer
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11
#3
In reply to #1

Re: Selection of Power Cables

01/08/2012 2:20 AM

Thank you my friend, more power! Good Luck
Register to Reply
Tim in Mexico
Guru

Join Date: Jul 2008
Location: Anywhere I may be at the time
Posts: 661
Good Answers: 16
#10
In reply to #1

Re: Selection of Power Cables

01/08/2012 4:11 PM

You're right, there are hundreds of calculators, conversion tables, etc just for the taking. Why dont posters do a little homework FIRST, then possibly ask if there determination is correct? If not why, etc.

Come on people, at least make an effort

Tim
Register to Reply
lyn
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#11
In reply to #10

Re: Selection of Power Cables

01/08/2012 4:14 PM

This question gets asked every day, too.

Register to Reply
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#2

Re: Selection of Power Cables

01/08/2012 2:20 AM

Obtain a copy of your local/regional electrical code; it gives the rules for determining conductor sizes. If your local jurisdiction has no such code, refer to the U.S. NEC (National Electrical Code) or a similar code from a region near you.

Conductor size is not generally calculated; it is looked up in tables, with modifications according to installation conditions.

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply Score 1 for Good Answer
Go to Next "Almost" Good Answer
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11
#4
In reply to #2

Re: Selection of Power Cables

01/08/2012 2:31 AM

Thanks my friend. More Power
Register to Reply
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11
#5

Re: Selection of Power Cables

01/08/2012 2:34 AM

My Friend in determining the circuit breaker of a unit, how you do it? What are the things to consider?
Register to Reply
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#6
In reply to #5

Re: Selection of Power Cables

01/08/2012 3:15 AM

This is a complex topic with varied requirements and approaches for many different circumstances. Again, local codes give guidance on it.

The key item to consider is the current needed to supply the load at its rated condition. Next is to account for any starting conditions that involve extra current for brief periods of time. (Magnetizing current for transformers and motors, starting current for motors until they attain full speed, high inrush current to incandescent lights, minor inrush to heaters, etc.)

For motors, wiring is sized for 1.25 x motor FLC/FLA; depending on type, fuses and circuit breakers are rated at 1.75 to 2.5 x motor FLC/FLA. (And other correction factors may apply if the load is continuous rather than intermittent.)

As you can see, this gets a bit complicated; and it depends on local standards.

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply Score 1 for Good Answer
No more "Almost" Good Answers.
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11
#7
In reply to #6

Re: Selection of Power Cables

01/08/2012 3:29 AM

Thanks for bearing with me and explaining it well. More power my friend.
Register to Reply
Oje
Active Contributor

Join Date: Feb 2010
Posts: 11
#8

Re: Selection of Power Cables

01/08/2012 4:40 AM

I hope you dont mind TORNADO, i wish i could get some drop knowledge you have. What are those correction factors if its continuous or intermittent. Sorry to bother you, hoping for your responds. Million thanks
Register to Reply
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33392
Good Answers: 1817
#9
In reply to #8

Re: Selection of Power Cables

01/08/2012 7:22 AM

That would be, not less than continuous load + intermittent load....

__________________
 All living things seek to control their own destiny....this is the purpose of life
Register to Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#13

Re: Selection of Power Cables

01/09/2012 3:39 AM

Er, why is power cable sizing in the Mechanical Engineering forum?

Stuff like this is bead-and-butter to qualified Electricians.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Register to Reply
Have a Different Question?
13 comments

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

Anonymous Poster (1); lyn (2); Oje (5); PWSlack (1); SolarEagle (1); Tim in Mexico (1); Tornado (2)

Previous in Forum: Grand Father Clock   Next in Forum: Sacrificial Anode Required by Client for Pipes Coated With Phenolic Epoxy

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Mechanical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (66 right now)
Show Members
Advertisement