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Re: [Amps] 240V Outlet

To: <maflynn@att.net>, "AMPS List" <amps@contesting.com>
Subject: Re: [Amps] 240V Outlet
From: "Carl" <km1h@jeremy.mv.com>
Date: Sun, 9 Aug 2009 21:49:07 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
We were discussing a #10  30A feed with 30A components. That is where the 
price jump gets painful.

You also failed to include the wall outlet.

Carl


----- Original Message ----- 
From: "Martin A Flynn" <maflynn@att.net>
To: "Carl" <km1h@jeremy.mv.com>; "AMPS List" <amps@contesting.com>
Sent: Sunday, August 09, 2009 9:00 PM
Subject: Re: [Amps] 240V Outlet


> Martin Wrote:
>>> Paul,
>>> The breaker and  device are the same rating.  My comment was to state
>>> that his recommendation was to make the conductors and ground one wire
>>> gauge larger then NFPA 70 states it should be.
>>>
>>> Martin
>> That only makes sense if the I*R drop is excessive. Since the Invader 
>> 2000 is only going to draw about half the ratings of #12 wire, then going 
>> to #10 makes little sense on a basement long run. Going to #10 requires 
>> all different plugs and outlets and the cost about goes thru the roof 
>> compared to a 20A feed.
> The FPN notes in  NFPA 70 (which is not part of the actual document) 
> suggests no more then a 5% total drop between feeder and branch circuits. 
> Here's the quote:  (fair use excerpt)
>
> Art 210-19(A)(1), FPN No. 4: "Conductors for branch circuits as defined in 
> Article 100, sized to prevent a voltage drop exceeding 3 percent at the 
> farthest outlet of power, heating, and lighting loads, or combinations of 
> such loads, and where the maximum voltage drop on both feeders and branch 
> circuits to the farthest outlet does not exceed 5 percent, provide 
> reasonable efficiency of operation.
>
> In the original case I commented on the run is ~50 feet, straight line 
> distance.  Service is 120/208 3 phase   A licensed electrician made the 
> calculations, presented them to the electrical inspector, and both agreed 
> that the oversize wire was appropriate.
> I did the same at home.  The difference in cost between #12 THHN and #10 
> THHN was negligible.  I used Square D breakers and Hubbell  connectors. 
> Since the  wire clamp range on a Hubbell HBL2410 -  20 Amp twist lock is 
> 18-10 AWG,  and the 20 amp 2 pole QOB Square D breaker  is 14-8 AWG, it 
> fit together fine with no difference in cost other then the wire.
>
> Martin
>
> 

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