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Old 08-19-2008, 04:29 PM   #1
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Can I double wire and increase amperage capacity?


I'm involved in a fairly extensive renovation of an old family home in KS. The future holds a radiant floor heating system for this home, and I'm getting ready to run the required wiring to support the mechanicals.

Basically the system will use a small pump to reciruculate the heating water in a closed loop system and the heat for the water will be supplied by a small electrical HWOD unit. The HWOD unit I'm eyeing requires a single double-pole 220-V/40A circuit breaker and 8 gauge wiring (2 wire w/ground) is recommended.

I foresee placing this HWOD unit in a place that would necessitate a pretty long piece of 8 gauge, and I would like to avoid that expense if possible. I do have a lot of 10-2/with ground laying around !

Sooooo.......would it be possible to use two lengths of that 10-2/wg, doubled up so that both lengths were hooked into the appropriate lugs on the breaker and ground bar in the breaker box and likewise connected to the correct corresponding lugs on the HWOD unit, to achieve the amperage capacity of 8 gauge?

I'm a big believer in doing it right the first time, so if this is a harebrained idea I'd like to know about it now. Otherwise, it would represent a significant savings if it is possible.

Just so y'all know, this is a very small town and therefore there are no codes to enforce nor any permits/inspections neccesary, much less available. I do have, however, a strong motivation to avoid the possibility of creating a fire hazard, so I definitely want whatever I do to be safe!!

I'll be finishing off the wiring and covering it all up on the next trip to KS in Sept., will tackle the plumbing part when I replace the water supply line from the meter to the house next summer.

As always, thanks in advance for whatever knowledge/advice you can share with me!

Dugly
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Old 08-19-2008, 04:48 PM   #2
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Can I double wire and increase amperage capacity?


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Originally Posted by YerDugliness View Post

Sooooo.......would it be possible to use two lengths of that 10-2/wg, doubled up so that both lengths were hooked into the appropriate lugs on the breaker and ground bar in the breaker box and likewise connected to the correct corresponding lugs on the HWOD unit, to achieve the amperage capacity of 8 gauge?
Absolutely not.... 310.4 would be the code violation.
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Old 08-19-2008, 05:46 PM   #3
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Can I double wire and increase amperage capacity?


The answer as stated above is no you can not.

Just for your knowledge what you are suggesting is done all the time with bigger wires, it is called parelling. Instead of useing a set 750KCM if you ran them in parellel you may get away with 2 seta of 4/0 or 250KCM a much smaller wire.
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Old 08-19-2008, 05:54 PM   #4
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Can I double wire and increase amperage capacity?


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Absolutely not.... 310.4 would be the code violation.
Thanks, Chris--any chance you can post a link so I can read what it says, or perhaps give me a reference I might be able to source at my local library (quite a nice library at that!)?

Thanks, again!

Dugly
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Old 08-19-2008, 05:59 PM   #5
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Can I double wire and increase amperage capacity?


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Thanks, Chris--any chance you can post a link so I can read what it says, or perhaps give me a reference I might be able to source at my local library (quite a nice library at that!)?

Thanks, again!

Dugly

I dont own the NEC CD so I have to hand type it...


310.4 Conductors in Parallel. Aluminum, copper-clad aluminum, or copper conductors of size 1/0 AWG and larger, comprising each phase, neutral, or grounded circuit conductor, shall be permitted to be connected iin parallel ( electrically joined at both ends to form a single conductor.)


take notice to the 1/0 AWG and larger part, that is the key to your question, your conductors are smaller than 1/0 AWG.


I didnt type out the exceptions, since non apply to your situation.
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Old 08-19-2008, 06:26 PM   #6
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Can I double wire and increase amperage capacity?


Thanks, Chris, I really appreciate the extra work! I understand now--will bite the bullet and buy the 8 gauge and will sleep well at night knowing I did it right !

Dugly
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Old 08-19-2008, 06:29 PM   #7
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Can I double wire and increase amperage capacity?


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I dont own the NEC CD so I have to hand type it...
Christmas is just around the corner.
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Answers based on the 2008 & 2011 NEC. If you're on the '14 already I feel sorry for you.
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Old 08-19-2008, 06:42 PM   #8
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Can I double wire and increase amperage capacity?


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I dont own the NEC CD so I have to hand type it...
I usually just post a link to the free online NEC on the NFPA site.

Jus' lika dis:

http://www.nfpa.org/catalog/services...%3Fid%3D7008SB

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Old 08-19-2008, 06:46 PM   #9
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Can I double wire and increase amperage capacity?


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Christmas is just around the corner.

I really want the 08 cd version, thanks speedy, your the best santa ever!
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Old 08-19-2008, 06:50 PM   #10
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Can I double wire and increase amperage capacity?


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I usually just post a link to the free online NEC on the NFPA site.

Jus' lika dis:

http://www.nfpa.org/catalog/services...%3Fid%3D7008SB


Nfpa site stinks with all the changes they made.
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Old 08-20-2008, 06:23 AM   #11
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Can I double wire and increase amperage capacity?


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I really want the 08 cd version, thanks speedy, your the best santa ever!
Me Too Santa Petey!!!!!!
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Old 08-20-2008, 07:53 AM   #12
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Can I double wire and increase amperage capacity?


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Originally Posted by Cow View Post
I usually just post a link to the free online NEC on the NFPA site.

Jus' lika dis:

http://www.nfpa.org/catalog/services...%3Fid%3D7008SB

Doesn't work for me. It wants me to sign in and then fill out a bunch of info. I then get an error message and get to start over. Over and over.
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Old 08-20-2008, 11:59 AM   #13
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Can I double wire and increase amperage capacity?


Chris et. al-

I have an electronic copy of the 2005 NEC in .pdf format. Is was cracked by a friend of mine so it is totally seachable, printable, etc.

If anyone wants a copy, feel free to PM me and I'll gladly forward a copy via email. If memory serves, I'll need an outside addy to send it to.

TTFN,
Jimmy
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Old 08-20-2008, 04:24 PM   #14
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Can I double wire and increase amperage capacity?


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Chris et. al-

I have an electronic copy of the 2005 NEC in .pdf format. Is was cracked by a friend of mine so it is totally seachable, printable, etc.

If anyone wants a copy, feel free to PM me and I'll gladly forward a copy via email. If memory serves, I'll need an outside addy to send it to.

TTFN,
Jimmy
You do realize this is totally illegal, right?
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Old 08-20-2008, 09:16 PM   #15
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Can I double wire and increase amperage capacity?


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You do realize this is totally illegal, right?
So is Limewire. Do you want a copy? I totally respect you, Nap, but puh-leeze. I'm sharing an electronic copy of the stupid code book, not Exile on Mainstreet. I don't know why people should have to buy it in the first place. I can go down to my village hall and read and copy it as I like. I'm not going to lose any sleep over sharing something that may help people who are interested in understanding/learning the electrical code.

Jimmy
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