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#80437 - 04/15/02 05:31 PM The code that ate my brain
sparky Offline
Member
Registered: 10/18/00
Posts: 5303
My calc's show a 5% VD on a 120v 20a circuit @ 75' , my ideal tester shows similar results. ALL the circuits I run when i wire a residence, save dedicated runs, are usually more than this length in total...

comments? suggestions? discussion?

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#80438 - 04/15/02 05:54 PM Re: The code that ate my brain
Chris Rudolph Offline
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Registered: 05/01/01
Posts: 160
Loc: Winter Park,Fl USA
Does this mean that all your 20 amp circuits with #12 wire are loaded to the full load of almost 20 amps,just shy of tripping the breaker?

Chris
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#80439 - 04/15/02 06:23 PM Re: The code that ate my brain
George Offline
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Registered: 02/23/02
Posts: 375
16amps is the correct design load for a 20amp circuit.

20amps is a lot of continous power for a residence. At 10amps and 120v you can go 150 ft before a 5% voltage drop on the same circuit.

I like to run 50amp 240v to subpanels and then feed 20amp circuits from those. It solves the voltage drop problem.
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#80440 - 04/15/02 08:26 PM Re: The code that ate my brain
ElectricAL Offline
Member
Registered: 10/10/01
Posts: 597
Loc: Minneapolis, MN USA
What does the PoCo deliver to the Bus in your area? Around the seven county Metro Area here I commonly measure 126 V to ground at the service disconnect.

With the standard set at 120, at what point do I start tracking 5% of which voltage?
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#80441 - 04/15/02 08:27 PM Re: The code that ate my brain
watthead Offline
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Registered: 10/13/01
Posts: 172
Loc: South Carolina
I would think that this is why most of us routinely install more than the minimum number of circuits required by code, and increase the conductor size when we run into the occasional circuit that is expected to be heavily loaded. This method will not produce the lowest possible installed cost, but it does allow you to sleep better, at least untill you get the service call for the 59 cent switch that failed.
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#80442 - 04/15/02 08:31 PM Re: The code that ate my brain
BrianSparky Offline
Member
Registered: 01/06/02
Posts: 38
Loc: Lakewood,CO
Hey Sparky,
Is that sculpture by DeVries?
-Brian
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#80443 - 04/16/02 02:49 AM Re: The code that ate my brain
sparky Offline
Member
Registered: 10/18/00
Posts: 5303
Quote:
16amps is the correct design load for a 20amp circuit.


agreed George....so we'd be looking for the 'dedicated' or maximum load. yet the ideal tester has a 15a & 20a setting. So to use the 15a setting on a 20a circuit would be close?

Quote:
Does this mean that all your 20 amp circuits with #12 wire are loaded to the full load of almost 20 amps,just shy of tripping the breaker?

Chris, i suppose an arguement could be made for a non-continuos load?

Quote:
What does the PoCo deliver to the Bus in your area?

Al, it's inconsistent, so another variable to deal with.

Quote:
Is that sculpture by DeVries?

Briansparky, dunno..ripped it off google...
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#80444 - 04/16/02 04:52 AM Re: The code that ate my brain
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
Sparky(s)

The Sculpture is a work by 'Edd Hayes'
You can see more at; http://www.eddhayes.com/

Some good stuff there.

Bill
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#80445 - 04/16/02 08:09 AM Re: The code that ate my brain
Bjarney Offline
Moderator
Registered: 04/10/02
Posts: 2527
Loc: West-Southern Inner-Northeast ...
Great picture, but one question...was his rod tested at the proper 100kV/foot level?
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#80446 - 04/16/02 05:17 PM Re: The code that ate my brain
Tom Offline
Member
Registered: 01/01/01
Posts: 1044
Loc: Shinnston, WV USA
I have only seen one voltage drop problem in a residence & it was a double wide that had to have near 150 feet of 14-2 to the furthest outlet. When one of those 12 amp vacuum cleaners was plugged into it, it about choked, voltage fell to 85-90 volts.

The homeowner had hired me to find code violations so he could sue the home builder.I found a few, but couldn't help him with the voltage drop problem.
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