Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Tool Talk Discussion Forum

Amps thru 2' No. 6

Welcome Guest, Log in or Register
Author 
Tim B from MA

03-02-2007 11:05:11




Report to Moderator

Can someone give me an idea of how many amps I can safely run through about 2 linear feet of No. 6 copper wire?

Currently have a 50 amp plug near the breaker box (thus the 2 linear feet) and am wondering if I can safely increase the amps withoug replacing the wire. Wire is in the wall.

Thanks.




[Log in to Reply]   [No Email]
A.P.

03-04-2007 03:24:09




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
What are you actually trying to accomplish? How large a load are you looking to handle? More information would make your question a whole lot easier to answer as you can probably see from the wide range of responses you received.



[Log in to Reply]  [No Email]
buickanddeere

03-03-2007 21:40:20




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
#6 RW90 will safely carry 100 amp in a free air application. 40 amp if it's TW installed in a raceway or as a cable.



[Log in to Reply]  [No Email]
Bus Driver

03-04-2007 05:22:23




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to buickanddeere, 03-03-2007 21:40:20  
In what reference chart or table would one find the 40 amp rating for #6 TW?



[Log in to Reply]  [No Email]
buickanddeere

03-04-2007 19:07:07




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Bus Driver, 03-04-2007 05:22:23  
Table #2 of the Ontario Electrical Code Book says 55 amp with copper #6 TW.Obviously I has a seniour's moment and used table #4 for Aluminum.



[Log in to Reply]  [No Email]
Charles (in GA)

03-02-2007 19:00:29




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
As others have noted, there are many variables.

Type of wire (Tw, UF, THHN, THWN, etc are examples of wire types, would be marked on the conductor insulation.

Number of wires in conduit or bundle. If no more than three conductors (example, two hot wires and a neutral, grounds not counted) then there is no derating. If you have more than three, then the wire's capacity must be derated.

Average ambient temperature of the area where the wire is located. If it exceeds 86f then wire capacity derating is necessary.

Temperature rating of the lugs or terminals that the wire is attached to. If a circuit breaker, it will state on the breaker what the rating is, such as 65c/76c or the like. You would also need to know the temp rating of the receptacle or whatever the wire is connected to on the other end. If any of these are less than what the wire is rated for, then the lower temp must be used in determining the capacity of the wire.

I'm sure there are other factors I haven't mentioned.

Simple question, complicated answer.

Charles

[Log in to Reply]  [No Email]
dave guest

03-02-2007 16:13:42




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
What are you feeding? Welder or what? Welder has duty cycle factor, also listed in the NEC. Welder rated for 50ampere primary probably only needs 30ampere in operation. If you can draw diagram for what you're gonna do.



[Log in to Reply]  [No Email]
JOHN HARMON

03-02-2007 12:18:16




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
Just went thru a wire size issue for the new Dual Fuel Kitchen Range we bought. Code calls for nothing less than 220/240 Volt ,50 Amps Breaker with 3/#6/wGrd.This line run was about 35'. For our new Range which is Electric Oven only, we had to furnish 220/240 Volt Service Entrance Box, ,40 Amp, Breaker using 3/#8/w/Grd Copper Wire. Same Footage. Conduit requirement was 1 1/2" EMT. Line was new so Permit was required from County and the Installation after inspection was Permitted by the Code Compliance Officer. Cost of Electrical Service to the Stove about equaled the cost of the Stove. Should have just replaced the old all Gas Range with a new all Gas Range,but I am not in charge around here,So! John

[Log in to Reply]  [No Email]
Denny 2

03-02-2007 12:06:33




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
According to art. 310.16 of the NEC # 6 wire is good for anywhere between 55 and 75 amps depending on the wires insulation, with no more than 3 current carrying conductors in a raceway. Dont confuse yourself with voltage drop, in that short of a run it is not a factor.



[Log in to Reply]  [No Email]
jdemaris

03-02-2007 11:41:57




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
It depends if you're running 240 VAC or 120 VAC. Also - the safety issue is using a wire that heavier than it's fuse or breaker. But, voltage drop is an entirely different matter. Most of the time, a 2% voltage drop is fine. Going with that -

#6 copper can safely carry 100 amps at 240 VAC as far as 55 feet (but cannot be TW type wire).

#6 copper can safely carry 50 amps at 120 VAC for 55 feet. I don't believe code allows any amp rating higher then 50 amps on a 120 VAC line with #6 copper -regardless of how short the run.

[Log in to Reply]  [No Email]
Joe(TX)

03-02-2007 13:33:54




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-02-2007 11:41:57  
jdemaris
It goes not matter what the voltage is when determining amperage capacity.
The only way it can carry 100a is single conductor and high temperature insulation.



[Log in to Reply]  [No Email]
Bus Driver

03-02-2007 12:13:22




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-02-2007 11:41:57  
The tables in NEC Article 310 do not at all support the idea that higher voltage permits higher amperage through a specific size conductor. For type TW insulation, the amperage rating for #6 copper is 55. Other insulation types MAY have higher amperage ratings, depending on the temperature rating of the terminating lugs and possibly other factors. 100 amps on #6- I can find no such rating in the NEC.

[Log in to Reply]  [No Email]
jdemaris

03-02-2007 13:18:44




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Bus Driver, 03-02-2007 12:13:22  
My NEC chart shows #6 copper conducter, calculated with a 2% voltage drop - can carry a maximum of 100 amps, 24,000 watts at a max. length of 55 feet at 240 VAC. TW may not be used, nor any other wire unless it it rated at the proper ampacity. For example, #6 copper with weatherproof coating in free-air is rated at 130 amps. #6 copper type RH, RHW, and THW rated 95 amps in free air. #6 copper RH, RHW,and THW in conduit or buried rated 65 amps. #6 copper type TW in conduit or buried rated at 55 amps.

[Log in to Reply]  [No Email]
Bus Driver

03-02-2007 13:44:15




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-02-2007 13:18:44  
Which Table of the NEC are you using? The ratings in free air are for single conductors suspended in open air. The 55 amp rating is for conductors in cables or in conduit. The 55 amp rating for TW (Table 310.16) is the only one that applies inside residences. Misinterpretations of the NEC can be extremely dangerous. I stated the true correct facts in my earlier post.



[Log in to Reply]  [No Email]
jdemaris

03-02-2007 14:00:52




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Bus Driver, 03-02-2007 13:44:15  
I didn't misinterpet a thing. I never said that HE could use #6 to carry 130 amps in his situation. I was listing the different possible ratings for #6 in copper in all extremes.

Misinterpreting can be a problem with anything - certainly not just wiring.

And, in regard to you - I never said anything about the truth value of your posts - one way or the other.



[Log in to Reply]  [No Email]
Sparky Bob

03-02-2007 18:05:46




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-02-2007 14:00:52  
Bus Driver is quite correct here.
To be honest there is NO definitive answer to an ampacity question. There are too many factors involved.

I am also VERY curious as to where you fine #6 able to carry 130 amps. Also, where do you find an exemption to using TW?


Also, it is almost a non-issue to ever use the 90 deg C column in figuring ampacity. We must use the column of the temperature of the lowest rated item in the circuit. Very few things, aside from conductors, are rated at 90 deg C.
For conductors in conduit we mostly use the 75 deg column.

[Log in to Reply]  [No Email]
Bus Driver

03-02-2007 14:56:27




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-02-2007 14:00:52  
Your original post is easily misinterpreted by the unknowing and is very dangerous. I cannot ignore that. My first response was not personal at all. Never have you listed the "NEC chart" you supposedly quote. If we want to get personal, so be it.



[Log in to Reply]  [No Email]
jdemaris

03-03-2007 07:18:49




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Bus Driver, 03-02-2007 14:56:27  
I see . . you don't want to get personal, yet you are the one that replied directly to my comments - with

�Misinterpretations of the NEC can be extremely dangerous"

and . .

"Never have you listed the "NEC chart" you supposedly quote"

I listed possible extreme uses of #6 cable - that's all - in response to part of the apical query - i.e.

". . . how many amps I can safely run through about 2 linear feet of No. 6 copper wire. . ."

And in regard to the NEC specs I "supposedly quote" seems you have already cited them yourself.

The free-air use of #6 was something that came to mind since - when I worked for Public Service Elec. & Gas as a lineman years back, I had to repair many a three-wire 100 amp service that used #6 cable.

[Log in to Reply]  [No Email]
Bus Driver

03-03-2007 08:50:27




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to jdemaris, 03-03-2007 07:18:49  
The man said SAFELY and he said that the cable is in the wall. Your post was dangerous and not at all helpful for the original question. Your "Chart" is not be from the NEC at all but might be from the NESFC. The NESFC does not apply to buildings at all except for those directly used and controlled by the utilities for purposes of power generation and distribution.



[Log in to Reply]  [No Email]
jdemaris

03-04-2007 06:30:07




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Bus Driver, 03-03-2007 08:50:27  
This is getting a bit silly. My reference to open air, three wire services was for residential and farm entrance cables. And, some of that is STILL permitted under NEC if it's old work. Just had an old knob&tube wired building that passed inspection. I think I made it quite clear that I was NOT telling the guy he could stick #6 conductor in his wall and run 100 amps.



[Log in to Reply]  [No Email]
Bill in IN

03-02-2007 11:18:22




Report to Moderator
 Re: Amps thru 2' No. 6 in reply to Tim B from MA, 03-02-2007 11:05:11  
Unless theres some insulation quirk it shouldn"t be a problem.



[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters

Website Accessibility Policy