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Default #6 NM wire in 1/2" hole?

Hi,
I'm running a 6-3 Romex NM-B with ground for my new air conditioner system.
My main panel doesn't seem to have any spare (unoccupied) 3/4" size punch outs left; but there is a 1/2" punch out. It is possible for me to fit this 6-3 with ground in there, but does anyone know whether this is prohibited by the NEC?
All advice (and NEC references) appreciated!
Regards,
Theodore.

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Default #6 NM wire in 1/2" hole?

On Mon, 21 Jul 2014 17:23:30 -0600, Tony Hwang
wrote:

Doug Miller wrote:
wrote in
:

Hi,
I'm running a 6-3 Romex NM-B with ground for my new air
conditioner system. My main panel doesn't seem to have any spare
(unoccupied) 3/4" size punch outs left; but there is a 1/2"
punch out. It is possible for me to fit this 6-3 with ground in
there, but does anyone know whether this is prohibited by the
NEC? All advice (and NEC references) appreciated!


I doubt very much that this would meet Code. First of all, you can't just pass the cable
through the knockout hole -- for the protection of the cable and the connections, Code
requires some sort of fitting on the hole (e.g. a cable clamp aka "Romex connector") which
secures the cable to the box. And I can't imagine that any fitting which would fit a 1/2"
knockout is listed for use with anything as large as 6-3; for example, the Romex connectors
used with 1/2" knockouts are listed for 14-2 through 10-3.

Does the panel have any vacant 1" knockouts? Or can you ream the 1/2" hole to 3/4"?

Hi.
The length of cable must be long, otherwise wouldn't 8-3 do? Enlarging
hole is easy using rimmer, cabinet is not really heavy gauge steel.

I assume you mean a reamer - which leaves all kinds of conductive
swarf all through the panel. The only RIGHT way to do it is with a
"knoclut punch" - aften referred to by the most common brand - a
"greenlee punch" Any electrician worth his salt will have one. All you
get that way is a metal ring.
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Default #6 NM wire in 1/2" hole?

Tony Hwang wrote in :

The length of cable must be long, otherwise wouldn't 8-3 do?


Conductor size is determined by amperage, not by length.

Enlarging hole is easy using rimmer,


LMAO! The tool he needs is a *reamer*. A "rimmer" is something altogether different.

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Default #6 NM wire in 1/2" hole?

On Monday, July 21, 2014 7:17:12 PM UTC-4, Doug Miller wrote:
wrote in

:



Hi,


I'm running a 6-3 Romex NM-B with ground for my new air


conditioner system. My main panel doesn't seem to have any spare


(unoccupied) 3/4" size punch outs left; but there is a 1/2"


punch out. It is possible for me to fit this 6-3 with ground in


there, but does anyone know whether this is prohibited by the


NEC? All advice (and NEC references) appreciated!




I doubt very much that this would meet Code. First of all, you can't just pass the cable

through the knockout hole -- for the protection of the cable and the connections, Code

requires some sort of fitting on the hole (e.g. a cable clamp aka "Romex connector") which

secures the cable to the box. And I can't imagine that any fitting which would fit a 1/2"

knockout is listed for use with anything as large as 6-3; for example, the Romex connectors

used with 1/2" knockouts are listed for 14-2 through 10-3.



Does the panel have any vacant 1" knockouts? Or can you ream the 1/2" hole to 3/4"?


Aside from that, does he really need #6 for an AC? Presumbably a home AC?
I have a 5 ton, which I believe is the largest made and it's rated for #8. I
wonder if he's sizing based on breaker, instead of sizing based on the
install instructions and eqpt rating. Meaning I have a 50 amp breaker on
my 8 gauge, 5 ton and it's to code because it's a motor load, not an oven.
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Default #6 NM wire in 1/2" hole?

trader_4 wrote in news:33f37dfc-9d21-481f-9d0e-b98ec7ca68b6
@googlegroups.com:

Aside from that, does he really need #6 for an AC? Presumbably a home AC?
I have a 5 ton, which I believe is the largest made and it's rated for #8. I
wonder if he's sizing based on breaker, instead of sizing based on the
install instructions and eqpt rating. Meaning I have a 50 amp breaker on
my 8 gauge, 5 ton and it's to code because it's a motor load, not an oven.


Whether he needs AWG-6 or AWG-8 is not really relevant -- neither one is listed for use with
any Romex connector or clamp that I'm aware of which will fit in a 1/2" knockout.

Another question for the OP: do you really need 6-3 (or 8-3, as the case may be) for an air
conditioner? If it's central AC, it's almost surely a pure 240V load, and 2-conductor cable will do
-- and if it's a window AC, 10-3 is almost surely sufficient.

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Default #6 NM wire in 1/2" hole?

On Tue, 22 Jul 2014 01:10:49 +0000 (UTC), Doug Miller
wrote:

trader_4 wrote in news:33f37dfc-9d21-481f-9d0e-b98ec7ca68b6
:

Aside from that, does he really need #6 for an AC? Presumbably a home AC?
I have a 5 ton, which I believe is the largest made and it's rated for #8. I
wonder if he's sizing based on breaker, instead of sizing based on the
install instructions and eqpt rating. Meaning I have a 50 amp breaker on
my 8 gauge, 5 ton and it's to code because it's a motor load, not an oven.


Whether he needs AWG-6 or AWG-8 is not really relevant -- neither one is listed for use with
any Romex connector or clamp that I'm aware of which will fit in a 1/2" knockout.

Another question for the OP: do you really need 6-3 (or 8-3, as the case may be) for an air
conditioner? If it's central AC, it's almost surely a pure 240V load, and 2-conductor cable will do
-- and if it's a window AC, 10-3 is almost surely sufficient.

Wire size is PRIMARILY dictated by load, but cable length comes into
play due to excessive voltage drop. You can never go wrong going one
size oversized.
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Default #6 NM wire in 1/2" hole?

On 07/21/2014 06:30 PM, wrote:
Hi,
I'm running a 6-3 Romex NM-B with ground for my new air conditioner system.


That must be one bad ass air conditioner. Wouldn't want your electric bill.



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Default #6 NM wire in 1/2" hole?

Hi, I'm the OP.
Yes, the mini split a/c system specs explicitly call for a 50amp breaker and #6 AWG (although I shudder to think that it'll actually use that much, with a 16 SEER).

I think I answered my own question by finding several "conduit fill charts" online that say 1/2" conduit can only have 2 #6 wires, so rules are there to keep me safe and I'm fine with that.

I also failed to notice one last 3/4" knock-out, so I'll be using that one.
Many thanks to all the good technical solutions and suggestions!
Regards,
Theodore.
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Default #6 NM wire in 1/2" hole?

On 07/22/2014 09:42 AM, trader_4 wrote:









Though your A/C is not likely to draw anywhere near 50 amps

continuously, it will have a very high initial startup current.



By using #6 wire the voltage drop should be minimal.


It's also minimal with #8 and the percent voltage drop difference
between #6 and #8 is insignificant. Which is why you can wire even a
5 ton AC with number #8.




I am sure you can but if the mfg says #6 I'd just go with what they say.


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Default #6 NM wire in 1/2" hole?

Hi, I'm the OP.
The unit is a Sea Breeze SMZ42H46ZOGX.
The instruction manual and even the promo literature explicitly calls out a 6AWG Stranded 3 Conductor cable, with a 50amp breaker.

Weird thing is that of the 3 conductors, it appears to send one to ground (http://i899.photobucket.com/albums/a...s3e1fd5ca.jpg). And since I have a "6-3 Romex NM-B with ground", I now seem to have an extra (unused) wire... the neutral.

Do you agree?
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Default #6 NM wire in 1/2" hole?

Sounds like you're suggesting they overcompensated, but I will not be so bold as to disregard a specification that explicitly says use 6AWG with a 50Amp breaker.
From the literatu

Rated Voltage & Frequency and Phase :208-230 / 1PH
Min./ Max. Operating Voltage :187 / 253 VAC
Circuit Breaker Size (A): 50
Min. Circuit Ampacity (A): 26
Wiring (Outdoor unit to Power Disconnect): 3C- 6 AWG (minimum)

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Default #6 NM wire in 1/2" hole?

On 7/21/2014 6:30 PM, wrote:
Hi,
I'm running a 6-3 Romex NM-B with ground for my new

air conditioner system.
My main panel doesn't seem to have any spare

(unoccupied) 3/4" size punch outs left; but there
is a 1/2" punch out. It is possible for me to fit
this 6-3 with ground in there, but does anyone know
whether this is prohibited by the NEC?
All advice (and NEC references) appreciated!
Regards,
Theodore.

On a practical note, I'd be sure to have a Romex
connector

http://www.contractcleanersupplies.c...-connector.jpg
in the punch out. Just to run the wire through the
hole leaves the risk of the panel metal wearing
through the insulation and causing a short.

How many tons of cooling? I remember using 10 AWG
for 2 1/2 ton system one time.


--
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Learn about Jesus
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Default #6 NM wire in 1/2" hole?

On Tuesday, July 22, 2014 6:43:07 AM UTC-4, Stormin Mormon wrote:
On 7/21/2014 6:30 PM, wrote:

Hi,


I'm running a 6-3 Romex NM-B with ground for my new


air conditioner system.

My main panel doesn't seem to have any spare


(unoccupied) 3/4" size punch outs left; but there

is a 1/2" punch out. It is possible for me to fit

this 6-3 with ground in there, but does anyone know

whether this is prohibited by the NEC?

All advice (and NEC references) appreciated!


Regards,


Theodore.




On a practical note, I'd be sure to have a Romex

connector



http://www.contractcleanersupplies.c...-connector.jpg

in the punch out. Just to run the wire through the

hole leaves the risk of the panel metal wearing

through the insulation and causing a short.



How many tons of cooling? I remember using 10 AWG

for 2 1/2 ton system one time.



I think Gfre might be on to something when he suggested it might
also have resistance electric heat and maybe that's why the need
for #6. If the OP gives the make and model we could probably find
the specs and install intructions and I'd like to take a look.
I'm still skeptical that a mini-split could really need #6. As I said,
my 5 ton central AC uses #8, but being AC only, it doesn't have any
resistance heat.
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Default #6 NM wire in 1/2" hole?

On 7/22/2014 8:37 AM, trader_4 wrote:
I think Gfre might be on to something when he suggested it might
also have resistance electric heat and maybe that's why the need
for #6. If the OP gives the make and model we could probably find
the specs and install intructions and I'd like to take a look.
I'm still skeptical that a mini-split could really need #6. As I said,
my 5 ton central AC uses #8, but being AC only, it doesn't have any
resistance heat.


OP had been providing some info, but now
I sense some resistance. We'll have to amp
it up a bit.

--
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Learn about Jesus
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Default #6 NM wire in 1/2" hole?

On 07/22/2014 07:45 AM, Stormin Mormon wrote:
On 7/22/2014 8:37 AM, trader_4 wrote:
I think Gfre might be on to something when he suggested it might
also have resistance electric heat and maybe that's why the need
for #6. If the OP gives the make and model we could probably find
the specs and install intructions and I'd like to take a look.
I'm still skeptical that a mini-split could really need #6. As I said,
my 5 ton central AC uses #8, but being AC only, it doesn't have any
resistance heat.


OP had been providing some info, but now
I sense some resistance. We'll have to amp
it up a bit.





Per Ohm's Law, to increase the current you will need to raise the voltage.
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Default #6 NM wire in 1/2" hole?

On 7/22/2014 2:22 PM, philo wrote:
On 07/22/2014 07:45 AM, Stormin Mormon wrote:
On 7/22/2014 8:37 AM, trader_4 wrote:
I think Gfre might be on to something when he suggested it might
also have resistance electric heat and maybe that's why the need
for #6. If the OP gives the make and model we could probably find
the specs and install intructions and I'd like to take a look.
I'm still skeptical that a mini-split could really need #6. As I said,
my 5 ton central AC uses #8, but being AC only, it doesn't have any
resistance heat.


OP had been providing some info, but now
I sense some resistance. We'll have to amp
it up a bit.





Per Ohm's Law, to increase the current you will need to raise the voltage.


Well, figuring a static load. What did you say?
I can't hear you with all that static.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..


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Default #6 NM wire in 1/2" hole?

It's strictly a heat pump/AC.
No resistance heat that I can see on the specs.
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Default #6 NM wire in 1/2" hole?

Hi Theodore,

I'm running a 6-3 Romex NM-B with ground for my new air conditioner
system. My main panel doesn't seem to have any spare (unoccupied) 3/4"
size punch outs left; but there is a 1/2" punch out. It is possible
for me to fit this 6-3 with ground in there, but does anyone know
whether this is prohibited by the NEC?


You can enlarge the 1/2" punch outs to accept a 3/4" cable clamp.

The ideal way to do this is with a knockout punch, but they tend to be
rather expensive for a one time job. Step drills will also work, but
they're almost as expensive as a knockout punch.

I went through this recently with my garage heater and used a metal nibbler
to enlarge the hole. You can see photos on this page ("Relocating the power
cord" about halfway down the page):

http://www.watsondiy.com/heater.htm

Be sure to turn off the main breaker before you start working in the panel,
and vacuum up any little metal bits that may fall inside the panel.

Good luck!

Anthony Watson
www.mountainsoftware.com
www.watsondiy.com
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Default #6 NM wire in 1/2" hole?

trader4 says: " It seems like they have established their own neutral,
unconneced to the service neutral, going to the other units. "

My assumption is that this is not a self-establised neutral, but the wiring control (from the indoor evaporator) that tells the outdoor condenser to switch from A/C to heat pump.

Side note: kind of strange to me that the indoor units are 220VAC. Call me paranoid, but
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