# Ampacity Chart Correct???



## Cletis (Aug 20, 2010)

I sure hope this wasn't/ isn't correct? If it is I've been running wrong wire for 10 yrs. 

I"m I reading this right that you can run a 1/0 Al URD direct burial for a 200 amp service??

I've been running 4/0 URD for them for forever. I use ugly's mostly for site decisions and never saw a chart for direct burial (just free air). 

Don't tell me it's true


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## 480sparky (Sep 20, 2007)

To what 'chart' do you refer?


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## McClary’s Electrical (Feb 21, 2009)

Cletis said:


> I sure hope this wasn't/ isn't correct? If it is I've been running wrong wire for 10 yrs.
> 
> I"m I reading this right that you can run a 1/0 Al URD direct burial for a 200 amp service??
> 
> ...


 


:blink::blink::no::no:


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## HARRY304E (Sep 15, 2010)

Cletis said:


> I sure hope this wasn't/ isn't correct? If it is I've been running wrong wire for 10 yrs.
> 
> I"m I reading this right that you can run a 1/0 Al URD direct burial for a 200 amp service??
> 
> ...


Ah no it not true . Your an Electrician and you should have the latest copy of the ,NATIONAL ELECTRICAL CODE. in your truck .

Take a look at table 310.15(B)(6) In your NEC if you even have one.

If you don't have one here is a link...http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=70


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## Speedy Petey (Jan 10, 2007)

I agree. The only "charts" you should be using are the tables in the NEC.


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## Cletis (Aug 20, 2010)

*Chart*

Sorry, forgot to post ampacity chart from manufacturer

http://buyawg.thomasnet.com/viewite...ble-aluminum-conductor-1040?&bc=100|1005|1021


I'll go look at book in the meanwhile


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## Speedy Petey (Jan 10, 2007)

Please ignore junk charts like that.


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## Speedy Petey (Jan 10, 2007)

_Table 310.15(B)(6) Conductor Types and Sizes for 120/240-Volt, 3-Wire, Single-Phase Dwelling 
Services and Feeders. Conductor Types RHH, RHW, RHW-2, THHN, THHW, THW, THW-2, 
THWN, THWN-2, XHHW, XHHW-2, SE, USE, USE-2



Table 310.16 Allowable Ampacities of Insulated Conductors Rated 0 Through 2000 Volts, 60°C Through 90°C
(140°F Through 194°F), *Not More Than Three Current-Carrying Conductors in Raceway, Cable, or Earth
(Directly Buried)*, Based on Ambient Temperature of 30°C (86°F)_​


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## Cletis (Aug 20, 2010)

*Chart*

Sounds good to me. I don't see how they can post that chart though. Looks like legit wire manufacturer. I've always use ugly's and code book for wire sizing. I just saw that chart and thought there may have been exception for direct burial. I noticed the ampacity is close to free air but when in conduit is closer to normal 310 ampacities.


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## Split Bolt (Aug 30, 2010)

Speedy Petey said:


> Please ignore junk charts like that.


Good advice! It doesn't matter what the manufacturer claims!:thumbsup:


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## Speedy Petey (Jan 10, 2007)

Right from that link:



> *Ampacity*
> 90oC conductor temperature, 20oC ambient, RHO 50, 100% load factor for three conductor triplex with neutral carrying only unbalanced load. Technical data for cable with solid black neutral is identical to yellow extruded stripe data. All yellow extruded stripe cable is XLP insulation. *To determine correct ampacity by conductor size, please consult the National Electric Code, latest edition.*


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## BBQ (Nov 16, 2010)

There are ways to use the manufactures ratings for NEC applications to do so adds junction boxes and terminals.

But lets say you do jump through the hoops to use the higher ampacity now voltage drop is going to be even worse then normal.


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## BBQ (Nov 16, 2010)

Here is an example I made before and it could be applied to even higher temperature conductors.


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## Cletis (Aug 20, 2010)

*Chart*

You would think someone at a large wire manufacturer would have a code book handy to post on their site of their wire ampacity's? 

Just curious. Isn't soil at 2 ft deep 57F? Wouldn't this in effect raise the ampacity of the conductors like free air? If so, shouldn't there be a factor for underground then?? 

Just askin


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## 480sparky (Sep 20, 2007)

Cletis said:


> You would think someone at a large wire manufacturer would have a code book handy to post on their site of their wire ampacity's?
> 
> Just curious. Isn't soil at 2 ft deep 57F? Wouldn't this in effect raise the ampacity of the conductors like free air? If so, shouldn't there be a factor for underground then??
> 
> Just askin



Soil cannot remove heat the way air can. Heated air can move away.... heated soil cannot.


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## BBQ (Nov 16, 2010)

Cletis said:


> You would think someone at a large wire manufacturer would have a code book handy to post on their site of their wire ampacity's?


The manufacturers sell wire to many users that are not under the NECs limitations.


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