[RE-wrenches] solid vs stranded AC vs DC

[boB Gudgel]

Wind-sun.com wrote:
> See http://en.wikipedia.org/wiki/Eddy_current
>
> The practical effects of running a single wire in 98% of the systems 
> that any solar installers will ever see is probably just about zero, 
> and it also only applies to AC currents (or rapidly varying DC, which 
> is not common). 
Won't make a noticeable difference in the small stuff in this industry 
most all of the time.

Brian Teitelbaum said:

Is that true even for non-ferrous metals, like aluminum, or say, gold?


Yes.  Anything that conducts electricity would be susceptible to eddy 
currents.  (IF it ~did~ create a problem that is)
I don't know why anyone here would normally run just one wire through a 
box or conduit though.

boB




> The only time I have ever actually seen this happen was several years 
> ago when the leads for a large 30 HP/440AC motor were fed by separate 
> wires, each in their own metal conduit (don't ask me why...).
>
> .................................................................................................. 
>
> Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
> Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
> .................................................................................................. 
>
> ----- Original Message ----- From: "Brian Teitelbaum" 
> <bteitelbaum at aeesolar.com>
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Sent: Monday, August 03, 2009 1:12 PM
> Subject: Re: [RE-wrenches] solid vs stranded AC vs DC
>
>
>> Hey Darryl,
>>
>> You said - " never allow a single wire to pass through a metal 
>> surface as this will induce eddy currents and magnetic effects into 
>> the metal causing voltage drop and heating"
>>
>> Is that true even for non-ferrous metals, like aluminum, or say, gold?
>>
>> Brian Teitelbaum
>> AEE Solar
>>
>>
>>
>> -----Original Message-----
>> From: re-wrenches-bounces at lists.re-wrenches.org 
>> [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of 
>> Darryl Thayer
>> Sent: Monday, August 03, 2009 1:01 PM
>> To: RE-wrenches
>> Subject: Re: [RE-wrenches] solid vs stranded AC vs DC
>>
>>
>> I looked in the code book and found stranded wire has about 2% higher 
>> DC resistance than solid, Chapter 9 table 8, and that for AC 
>> resistance the same value as DC resistance to within the table 
>> accuracy Chapter 9 Table 9
>>
>> This table points out that for AC resistance it is important to know 
>> the conduit system, as the reactance will have an effect.  With AC it 
>> is important to never allow a single wire to pass through a metal 
>> surface as this will induce eddy currents and magnetic effects into 
>> the metal causing voltage drop and heating.
>>
>> --- On Fri, 7/31/09, jay peltz <jay at asis.com> wrote:
>>
>>> From: jay peltz <jay at asis.com>
>>> Subject: Re: [RE-wrenches] solid vs stranded  AC vs DC
>>> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>>> Date: Friday, July 31, 2009, 10:01 PM
>>> Hi Darryl,
>>>
>>> But what are the differences and when do they come into
>>> play?
>>>
>>>
>>>
>>>
>>> On Jul 31, 2009, at 7:25 PM, Darryl Thayer wrote:
>>>
>>> >
>>> > Well there is very slight differences between AC and
>>> Dc But this
>>> > difference
>>> > is so slight that it has no effect on anything we will
>>> do.
>>> > Darryl
>>> > --- On Fri, 7/31/09, jay peltz <jay at asis.com>
>>> wrote:
>>> >
>>> >> From: jay peltz <jay at asis.com>
>>> >> Subject: [RE-wrenches] solid vs stranded  AC
>>> vs DC
>>> >> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
>>> >> Date: Friday, July 31, 2009, 7:00 PM
>>> >> HI All,
>>> >>
>>> >> I'm trying to understand this wire issue.
>>> >>
>>> >> Whether or not there is a difference between
>>> stranded or
>>> >> solid wire for DC or AC.
>>> >>
>>> >> Any takers on this one?
>>> >>
>>> >> thanks,
>>> >>
>>> >> jay
>>> >>
>>> >> peltz power
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>>
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