How Much Voltage Loss Is Acceptable? - Electrical - DIY Chatroom Home Improvement Forum

 DIY Chatroom Home Improvement Forum How much voltage loss is acceptable?
 Register Blogs Articles Rewards Search Today's Posts Mark Forums Read

02-18-2010, 08:54 AM   #1
Just call me Andrew

Join Date: Mar 2009
Location: Albany, NY
Posts: 2,265
Rewards Points: 1,020

## How much voltage loss is acceptable?

I understand how to easily calculate voltage drop using a calculator like this:

http://www.csgnetwork.com/voltagedropcalc.html

How do I know if the loss I calculate is acceptable? At what percent loss would one consider using larger wire? Or is it specifically determined by what you are going to be doing at the other end of the wire?

Thanks.

__________________
Andrew

02-18-2010, 09:27 AM   #2
Member

Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000

I'm not sure code dictates what is allowed...I have heard anywhere from 3-5% is OK
But in can depend upon the use
Incandescent lights will work OK on lower voltage & will last longer
So a long run down a driveway the voltage drop might be OK
But if at the end of the run is an electronic gate/motor then voltage drop might not be OK

 02-18-2010, 10:21 AM #3 Member   Join Date: Jan 2008 Location: Alabama Posts: 608 Rewards Points: 500 Here's at least one source for additional information. http://www.psihq.com/iread/faqvolt.htm The basic summary is that the NEC wants there to be no more than a 5% voltage loss on the farthest outlet of a fully loaded circuit (6 volts) The FAQ page makes it sound like there isn't a code specification on the issue, just a footnoted recomendation.

02-18-2010, 10:35 AM   #4
You talking to me?

Join Date: Dec 2007
Location: sw mi
Posts: 7,551
Rewards Points: 6,290

correct. The NEC does not demand anything concerning this. A FPN (fine print note) is only a recommendation, suggestion, or clarification. It holds no enforceable weight.
Quote:
Take note that there is a suggest 3% max voltage drop on branch circuits

and a 5% max voltage drop on feeders and branch circuits combined.

and that is to the furthest outlet.

 02-18-2010, 10:36 AM #5 Just call me Andrew   Join Date: Mar 2009 Location: Albany, NY Posts: 2,265 Rewards Points: 1,020 Thanks, good info here. __________________ Andrew
 02-18-2010, 10:54 AM #6 You talking to me?     Join Date: Dec 2007 Location: sw mi Posts: 7,551 Rewards Points: 6,290 We try to give you your money's worth.
02-18-2010, 11:01 AM   #7
Just call me Andrew

Join Date: Mar 2009
Location: Albany, NY
Posts: 2,265
Rewards Points: 1,020

Quote:
 Originally Posted by nap We try to give you your money's worth.
But i didn't pay any....wait a minute!
__________________
Andrew

02-18-2010, 11:15 AM   #8
Member

Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000

SendDaveonVacation@HoliDaves.com

 Thread Tools Display Modes Linear Mode

 Posting Rules You may not post new threads You may not post replies You may not post attachments You may not edit your posts BB code is On Smilies are On [IMG] code is On HTML code is OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post hyunelan2 Electrical 0 10-12-2009 12:25 PM WShawn Electrical 7 08-19-2008 06:22 AM tonyBagadonuts Electrical 19 07-20-2008 07:15 PM sushiboy Electrical 12 04-03-2008 09:01 PM l.schrankel@comcast.net Electrical 2 03-04-2007 09:38 AM

Top of Page | View New Posts