[Amps] 240V Outlet

[Charles Harpole]

I always use #10 wire in this application and
then use an electric dryer fixture for the plug
and socket on the wall.  The pig tail end of
the dryer cord (opposite the molded plug) goes to my 
operating bench DPST breaker from which 
the whole bench is then powered.  I turn off
the breaker after every ending time on air.
73,

Charles Harpole
k4vud at hotmail.com   





> From: km1h at jeremy.mv.com
> To: maflynn at att.net; amps at contesting.com
> Date: Sun, 9 Aug 2009 21:49:07 -0400
> Subject: Re: [Amps] 240V Outlet
> 
> 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 at att.net>
> To: "Carl" <km1h at jeremy.mv.com>; "AMPS List" <amps at 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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