Wind Turbine wire size

55 Posts
Apr 26, 2009 12:07 pm
Wind Turbine wire size

I just got a 150W wind turbine and I think I need to use 10 ga stranded wire. I am going 50 ft total.I have a 12v system but that is being regulated 3ft from the batt. So I am being told that this Gen will max volt at 36-40. Do you think 10ga will work?
 
Apr 26, 2009 06:19 pm
Re: Wind Turbine wire size

Its being regulated 3 ft. from the battery so its not an integral regulator so, what would be its max. amps at cutout speed?
I am no expert but...
Just dividing 150 by 12 = 12.5 amps.
#10 awg THHN is rated for 30 amps.
What size wire leads, if any, are coming off of the wind genny?
If there is any doubt, go to #8 awg THHN, its rated for 40 amps. That should more than make up for any line loss. Especially at only 53 ft.
 
351 Posts
Apr 26, 2009 11:08 pm
Re: Wind Turbine wire size

#10AWG is rated at 30amps for 120VAC.  You hit the 5% voltage drop at about 100 feet. For 12VDC and 12.5 amps, it is good for about 24 feet.
The 40 amps for #8 is also a 120VAC rating.

You need a #6 AWG to carry 12.5 amps 53 feet at 12VDC. It would yield a 4.48 percent voltage drop according to my calculator.

Is the 53 feet the entire run including the vertical drop from the turbine ?  Or, is it the horizontal distance between the tower location and the batteries ?

 
55 Posts
Apr 27, 2009 07:57 pm
Re: Wind Turbine wire size

53ft is the total run. However tonight with bargaining I might of shaved some of that distance off. Got a better location but I may be planting flower at the base of the pole.I am going to have to remeasure and repost for the groups opinion.
 
33 Posts
Apr 30, 2009 08:01 pm
Re: Wind Turbine wire size

53ft is the total run. However tonight with bargaining I might of shaved some of that distance off. Got a better location but I may be planting flower at the base of the pole.I am going to have to remeasure and repost for the groups opinion.

Good idea to go with market. You can get 50ft 6 guage amp kits that would be cheap and ideal for install.
 
May 1, 2009 04:28 pm
Re: Wind Turbine wire size

Not so Ken. Not trying to "pick nits" but THHN is also rated for up to 600 volts.
So, #10 awg THHN is rated for 30 amps any where from -1 volt up to 600 volts with no distinction between VAC or VDC. Its makes no difference. Amps are amps just like watts are watts, VAC or VDC.

http://www.mikeholt.com/technical.php?id=nec/unformatted/conductor&type=u&title=Conductor%20Sizing%20(11-19-99)

But I agree that I was hasty in saying "If there is any doubt, go to #8 awg THHN, its rated for 40 amps. That should more than make up for any line loss. Especially at only 53 ft."

There is indeed a greater voltage drop for a given distance at lower VDC than higher VAC. Just one, of the biggest reasons AC won out over DC in the AC/DC "war" between Edison and Tesla. Something I didn't take into consideration.
Which I don't know, maybe its an open circuit voltages or something. Who knows? We don't even know the name brand of this wind genny. It could be a homemade on the brake disks from a Volvo or something. Not that there is anything wrong with that mind you. http://otherpower.com/

"Just dividing 150 by 12 = 12.5 amps."

What would be the percentage of voltage drop with #8 awg THHN at 53 foot at 12 VDC nominal with 12.5 amps?
« Last Edit: May 1, 2009 06:31 pm by Thomas Allen Schmidt »
 
May 1, 2009 05:41 pm
Re: Wind Turbine wire size

Ha! Here it is.
http://otherpower.com/wardalt.html
I couldn't find it a while a go.

Just some fun reading, maybe?
http://staff.fcps.net/rroyster/war.htm

Actual voltage drop calculator.
http://www.currentsolutions.com/knowledge/vdrop.htm
Try different size conductor; #10, #8, #6, #4, 3, 2, 1, 1/0 etc. etc.. Its fun, really.

Indeed, at; 12 vdc, 12.5 amps, 106 (2x53) foot of #8 there would be a voltage drop of .81 almost a whole volt. Opps. Sorry 'bout that Max.

With #10, a voltage drop of 1.5

With #6, - .53

Interestingly enough, with #4 - .33
« Last Edit: May 1, 2009 06:26 pm by Thomas Allen Schmidt »
 
351 Posts
May 2, 2009 02:23 am
Re: Wind Turbine wire size

Thomas
Here is a calculator that I find more useful. It is good for both ac and dc.

http://www.powerstream.com/Wire_Size.htm

Ken
 
19 Posts
May 2, 2009 04:40 pm
Re: Wind Turbine wire size

Not so Ken. Not trying to "pick nits" but THHN is also rated for up to 600 volts.
So, #10 awg THHN is rated for 30 amps any where from -1 volt up to 600 volts with no distinction between VAC or VDC. Its makes no difference. Amps are amps just like watts are watts, VAC or VDC.

http://www.mikeholt.com/technical.php?id=nec/unformatted/conductor&type=u&title=Conductor%20Sizing%20(11-19-99)

But I agree that I was hasty in saying "If there is any doubt, go to #8 awg THHN, its rated for 40 amps. That should more than make up for any line loss. Especially at only 53 ft."

There is indeed a greater voltage drop for a given distance at lower VDC than higher VAC. Just one, of the biggest reasons AC won out over DC in the AC/DC "war" between Edison and Tesla. Something I didn't take into consideration.
Which I don't know, maybe its an open circuit voltages or something. Who knows? We don't even know the name brand of this wind genny. It could be a homemade on the brake disks from a Volvo or something. Not that there is anything wrong with that mind you. http://otherpower.com/

"Just dividing 150 by 12 = 12.5 amps."

What would be the percentage of voltage drop with #8 awg THHN at 53 foot at 12 VDC nominal with 12.5 amps?


In this instance Ken Hall is right.  Not only are the underlying numbers of those tables calculated using 120V AC as a reference or baseline, but they also don't take into account the derating of the wire that normally occurs when you use it in places that are exposed to temperature extremes as in DC installations outdoors, particularly in reference to heat.
Those tables are based on wire in an insulated wall.  Not on wire running on a roof or up a tower, etc.

Bigger is better. #6 looks correct.
 
May 3, 2009 01:58 pm
Re: Wind Turbine wire size

I am telling you "Fred Flintstone" or whatever your name really is, VAC or VDC it makes no difference to the amperage ratings of cooper wire insulated with THHN - Thermoplastic High Heat-resistant Nylon.
What "tables" are you referring to? NEC?
Are you saying that the amperage ratings listed in the NEC for THHN are only good for 120 VAC indoors, period?
If yes, then according to you, what wire insulation is rated for VDC circuits by NEC? Be specific please, about which tables.
Wow, look at me, arguing about copper wire insulation with a guy who wants to be know as a cartoon character from the stone ages.Smiley
A little constructive criticism "Fred Flintstone." If you want to be taken seriously, try using your real name.

I dare anyone to show absolute proof on this board that the amperage ratings for THHN insulated copper wire, as listed anywhere in the National Electrical Code is only good for voltages of alternating currents!
 
May 3, 2009 03:30 pm
Re: Wind Turbine wire size

Max Shulte. I was in no way, nor am I now, trying to "trick" you or anyone else into using the wrong type or size of wire for your electrical installation despite what others on this board might be implying to make you or anyone else believe.

I admitted in my second posting that I did not take into consideration, voltage drop, in my first posting. Not because I don't know of such things but because of hast. I do not contest any references made to that fact by others in this thread. I did not make any claims that this would be the best type (although I did imply that #8 should be of a sufficient size) of wire for your installation. I do however stand by my claims that, volts ac or volts dc it makes no difference to the amperage ratings per NEC of THHN - Thermoplastic High Heat-resistant Nylon coated copper wire.

Perhaps these PDF files would be of interest to you or anyone else following this thread.
http://www.nmsu.edu/~tdi/pdf-resources/cc47.pdf
If you notice that THHN is used in the low voltage dc side of a PV system wiring diagram.

http://www.zetatalk.com/energy/tengy10s.pdf
Also, please take notice of the reference on page 4 of 11 to "Use this table for high voltages of 120 or higher." It makes no reference to volts ac or dc. I was actually being conservative when I stated #8 awg. THHN being rated for 40 amps. As well on page 2 of 11, the paragraph on "Wind Generators Circuits."

I iterate - I dare anyone to show absolute proof on this board that the amperage ratings for THHN insulated copper wire, as listed anywhere in the National Electrical Code is only good for voltages of alternating currents!
 
May 3, 2009 05:08 pm
Re: Wind Turbine wire size

With fairness in mind, what Mr."Flintstone" is referring to when he states -�  "but they also don't take into account the derating of the wire that normally occurs when you use it in places that are exposed to temperature extremes as in DC installations outdoors, particularly in reference to heat." can be cleared up with these two PDF files.
(A preemptive side note; check out the opening paragraph with reference to "wind power installers.")
http://photovoltaics.sandia.gov/docs/PDF/awgcdcrnr.pdf

http://photovoltaics.sandia.gov/docs/PDF/whrtocdcrnr.pdf

While I am here, Mr."Flintstone", about that challenge for proof, saying "the Great Kazoo told me so" will not be considered as proof.
« Last Edit: May 3, 2009 05:13 pm by Thomas Allen Schmidt »
 
19 Posts
May 3, 2009 08:16 pm
Re: Wind Turbine wire size

Believe what you want to believe, it matters little to me.  But if you're wondering why your wind or solar installation does a crapping job of selling power back to the electric company and/or keeping your battery bank charged, you'll know what the answer is.
 
55 Posts
May 5, 2009 08:30 pm
Re: Wind Turbine wire size

I would like to thank everyone for all of the information I am going to have to grind thru. Right now I have put up a temporay pole and have begun testing this wind turbine I have purchased. I am certain I will be back with more Questions on a fresh topic line.
Max
 
May 6, 2009 08:17 pm
Re: Wind Turbine wire size

Its good to know that the people who put together the National Electrical Code have our safety in mind when they rate these wires and there insulations types.
The NEC bases the amperages of these wires on wether they are copper or aluminum, on there size and, on the temperature its particular type insulation can withstand safely amoung other things. The NEC does not base these amperage ratings on voltage drop.

To say a #10 awg THHN wire is good for 30 amps per NEC is saying thats the maximum size fuse or breaker it can be placed on. There are of course several NEC de-rating factors that have to be applied depending on its particular use. Voltage drop is not one of them. Nether is ac or dc voltages.

Voltage drop "de-rating" is applied in an effort to maximize efficiency's. That applies to ac and dc voltages and in the case of THHN copper wire, from 0 up to 600 volts.

There are a lot of places where, for example, on general use 20 amp 120 vac receptacle circuits, the first 50 foot of the circuit is specified to be no less than #10 awg THHN even though the entire circuit is only 300 foot in wire length.

Its a good thing too that there are people putting together charts that take into consideration things such as voltage drop in low voltage dc circuits to maximize power production from such devices as wind gennys and photovoltaics and loads as well such as low voltage dc lighting.

For someone to say "#12 awg THHN is only good for 5 amps" (at 12 vdc nominal over a span of 20 foot) is correct but that doesn't change the fact that #12 awg THHN is good for 20 amps maximum. 460 vac or 12 vdc.

Perhaps its time for the NEC to take low voltage dc, "voltage drop" into consideration? Maybe include a table or two?

Thank you Oso.
« Last Edit: May 6, 2009 08:25 pm by Thomas Allen Schmidt »
 

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