Far more likely they apply the correct section of Code for the purpose
It would be far better to reference the specific Code in question or
even the controlling jurisdiction which would likely lead to being able
to find the relevant Codes in play. I strongly suspect if that were
done it would be found that the installation under discussion is
compliant there as well.
On Mon, 04 Mar 2013 12:50:54 -0600, The Daring Dufas
I have been a certified, state licensed electrical inspector for about
Florida and we follow the NEC state wide, unaltered, except for
requiring bonding of steel studs.
I said before, this is a common question on the inspector tests and if
you say 8ga on a 40a breaker for a motor circuit like this, you got
that one wrong.
Maybe your inspectors are not certified and it is just the mayor's
nephew who learned his trade from the Time Life electrical wiring for
On 3/4/2013 2:15 PM, firstname.lastname@example.org wrote:
That's what they want around here with a disconnect at the condensing
unit. I've always gone by the breaker size required by the label on the
unit and sized the wiring for the breaker and that's what the inspectors
want. If you were the inspector at the site, I would do what you
demanded. It can't be simpler than that. Of course, different insulation
types handle different currents. I don't argue with the inspector and do
what their department requires. The inspectors around here would reject
a 40 amp breaker on #10 copper 60°C NM/UF cable. Higher temp rated wire
insulation would be different. NEC Table 310-16. I would put a 40amp
breaker on #10 copper if it has 90°C rated THHN/THWN/XHHW insulation. O_o
On Mar 4, 3:15 pm, email@example.com wrote:
It's also possible that he's basing his experience on what's required
by what he's used and had passed. Of course if you use
8 gauge where a minimum of 12 gauge or 10 gauge is required, it
passes because it meets code. And the inspector isn't likely to
BTW did you know that 12 was sufficient? So, he goes on
thinking that 8 gauge is what is required for it to pass.
Obviously there hasn't been any discussion with an inspector
about the issue, otherwise he'd be able to give us the code
section that the position is based on. He refuses to recognize
that the code treats breaker requirements for general purpose
branch circuits differently than it does for motors, AC eqpt, etc.
On Mar 4, 1:50 pm, The Daring Dufas <the-daring-du...@stinky-
When you can give us the section of the NEC where you can
conclude that there is something wrong with Mikepier's
installation, under ANY interpretation, then we can discuss differing
interpretations. If an inspector is going to fail it, then he should
able to tell you that per NEC section X.Y, it's not allowed.
This isn't the first time this issue has come up. And the result is
usually the same. You have some people thinking that the same
rules for lights and receptacles under the NEC also apply to
motors and AC equipment. They don't. I would hope that
someone who installs that eqpt would understand the distinction.
On 3/4/2013 3:27 PM, firstname.lastname@example.org wrote:
If you'll look at NEC Table 310-16 you will see the amp rating for wire
size. It changes depending on the insulation on the wire. Every 40 amp
circuit I've ever installed in a home using 60°C NM/UF cable has been #8
copper. If I install a 40 amp circuit in conduit using 90°C THHN/THWN
insulated wire I'll use #10 copper. I don't usually run conduit in a
home. The last 4 ton AC condensing unit I installed used #14 THHN/THWN
copper in conduit. It was a 3ø unit that called for a 15 amp breaker. I
have to install what I know the inspector will pass and the inspectors
do look at the temperature rating of the wire and check if the circuit
breaker is HACR rated if it's hooked to an AC condensing unit. I don't
argue with the inspectors, you can if you wish. O_o
On Mar 4, 5:55 pm, The Daring Dufas <the-daring-du...@stinky-
And if you look at that table, it shows that 12 gauge is OK for
up to 25 amps. The nameplate on the AC eqpt Mike has says
the minimum circuit ampacity is 24.4 amps. Therefore, 12 gauge
meets the minimum requirement and is permitted.
The problem comes when you then try to tie the breaker to be
installed for that AC eqpt with the wire size and treat it like it
was a water heater, or a receptacle circuit. It is not. The eqpt
manufacturer's rating governs and it says that a breaker of
40A max is permitted.
15 amp breaker for a 4 ton AC? That ain't right.
It's not an issue of arguing with the inspectors. It's what the
NEC says disagrees with what you say. And if an inspector fails
something, he should be willing to tell you what part of the code
it failed and why, without getting into an argument. Any inspector
should know that motors are treated differently than resistive
Just do some googling. This whole issue has come up many
times. Some homeowner or inspector raises the issue of the
breaker for an AC being larger than would normally be permitted
for a light circuit, etc. that uses a given wire gauge. Or some home
inspector flags it. Then a lot of discussion follows and the folks
most knowledgable about the actual issues and code say
it's perfectly normal. In this case, you have gfretw, an actual
electrical inspector, telling you how it works and that what Mike
has is code compliant.
On 3/4/2013 6:12 PM, email@example.com wrote:
Did you look at the notes from the table? They are at the bottom of the
table and will show what I use and what the inspectors go by. You will
see a little note reference next to the 25 amp figure. ^_^
It is a 240 volt three phase unit and 15 amps 3ø power is what it calls
for. It has run without a problem for 10 years in three different
locations. I installed it at a pizza place which has moved twice after
I installed at their first location. I also use test equipment to check
the current draw and phase rotation on all three phase equipment. ^_^
If gfretw was the inspector in charge I would do what he said but I have
to go by what the inspectors here and now require. I also go by
the manufacturers requirements unless they clash with the inspector
who has final say. The city here actually has stricter guidelines in
some areas than the NEC. Here, they want the circuit and wire gauge
to match no matter what the load is with the only difference being that
HACR rated breakers be used on AC and refrigeration units. Understand
that the temperature rating of the insulation also determines the amp
carrying specification of the wiring for both copper and aluminum. ^_^
On Mon, 04 Mar 2013 20:36:50 -0600, The Daring Dufas
Absolutely. That note takes you to 240.4(D) which references 240.4(G)
G) Over current Protection for Specific Conductor Applications. Over
current protection for the specific conductors shall be permitted to
be provided as referenced in Table 240.4(G).
which references 440 part III & IV and 430 part III, IV, V, VI & VII
where we get this permission for larger OC devices and the ability to
use 310.16 at the listed rating.
Like I said, you need to read the whole code, not just the first thing
On Mon, 04 Mar 2013 22:21:55 -0600, The Daring Dufas
Whatever you need to do. You are just oversizing wire but as long as
you keep getting the bid, rock on.
You probably should have the conversation tho. I am curious how your
inspectors can ignore that label.
I replaced my 3-ton a/c unit after its 12-year old predecessor croaked as a
result of Hurricane Yikes*. The chap who replaced it said I could also swap
out the 40-amp breaker with a 30-amp one inasmuch as more modern units, mine
included, were more efficient and drew less power. Makes sense since the
original a/c unit was a builder model from the 1960's. The compressor unit,
no doubt, had been replaced, maybe more than once, before I bought the
house. But nobody every fiddled with changing the circuit breaker.
* The fellow who did the work is a Guatamalan off-the-books a/c technician.
Evidently he is part of a co-national underground network of repair people
in that he knew a guy who obtains and reconditions a/c units, some from
insurance companies after house fires. Anyway, the unit he chose was a
two-year old Trane, and the unit has been working swell for the past four
years. The whole business, compressor unit, installation, vacuuming, and
recharge cost $750.
One point is this: If you can find ONE immigrant tradesman, you've got
access, probably, to lots of others (roofers, sewer replacement, concrete
work, etc.). No, they're not bonded, insured, and so forth, but the proof is
in the pudding. If the job works, you're good. Besides, I know where Lewis,
the guy who did the work, lives - next door to my son - and Lewis knows I
have a gun.
Feel free to disagree, but this technique works for me.
Whatever works. I try to avoid government involvement in business
whenever I can because it tends to increase the cost of everything
but at the same time I'll do quality work and not slipshod crap which
gives folks a reason to complain to a government puke. ^_^
What about the outside disconnect? It is just simply a "pull-out" type
disconnect, no fuses, just solid copper buss bars. I don't see any
rating for it. How do I know it's rating? Or are all these type of
disconnects just a standard rating?
I personally don't like the pull out disconnects because they can
corrode from mishandling and pranksters can make off with the pull
out. I use the Square D dummy breaker in a rain proof box. It looks
like a standard Square D QO breaker but with no over current protection
and a real circuit breaker will actually snap-in in its place. ^_^
I can appreciate that. I remember a famous man saying something to the
effect, "Experience is a fool's best teacher." Believe me, I can admit
to being a fool on more than one occasion but I survived it and learned
from it. Years ago, I trained in martial arts and got knocked on my butt
numerous times but I learned from it to the point that my instructors
couldn't get through my coverup and I could block kicks and punches. Of
course now, a couple of five year old kids could take me. ^_^
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