nm grounds in panel and ac sizing...and aluminum wire?

[ritelec]

Hello......

Had a call to check panel for some issues a home inspector brought up for house sale inspection.

Multiple grounds twisted together on panel.

They are. One went to the bar......some grounds are insulated , some not.

I know if the bar is rated for it you can put 2 grounds in one lug if same size conductor.....
Can you splice several grounds together instead and bring one ground to the bar?
There a combination of 12's and14's..........can I make a splice to one twelve and ground it, or is there an article stating all grounds in a panel must terminate on the ground bar?
There all too short to reach the bar.....do I have to install another one to the enclosure closer to where they reach?

AC--

Saw two 12's on a 30 two pole... they went outside to the ac. Not on list of what inspector picked up but for my own head, or if someone wants me to sign off on electrical and not just
invoice for repairs mentioned.
rheem ac at least 10 yrs old

v- 208-230 1 phase
compress rla 18
lra 104
fan 2 hp1/3

max fuse or brk 40
min fuse or brk 30

min. supply circ ampacity 25

the wire is 12-2 nm older........(might be thw)
should I rate that from the 75 degree column at 25 and that is actually correct? the outdoor disconnect is rated for 50a I believe...couldn't tell, it was mucked up alittle...
mabe 30.


There's one 12-2 AL nm wire on a 15a which seems to go to a whole house fan.... should be ok right.
Short of pulling the ladder out to crawl in the attic, seams there would be only two points to question in that circuit, that I could see, is if the switch was al/cu rated and if the motor
had to feed with copper conductors only ???

Thank You

 

[ritelec]

Hey Rich...good to see your ok and still around............
Happy holidays all all that... :- )


As I see, theres no issue splicing the grounds in the panel an attaching that splice to the ground buss with one ground sized to your largest circuit of the grounds
being spliced.

The AC , although it's a max forty and a min thirty.............. the minimum size circuit of 25 is what you look at and as long as the wire is rated for that your good to go ...
Unless you feel like replacing it with 10's or 8's and making some work for yourself.....


The aluminum wire........don't sweat it......also good..

Catch you later..
Rich

 

[SmithBuilt]

min. supply circ ampacity 25

the wire is 12-2 nm older........(might be thw)
should I rate that from the 75 degree column at 25 and that is actually correct? the outdoor disconnect is rated for 50a I believe...couldn't tell, it was mucked up alittle...
mabe 30.

Thank You

You are still required to use the 60c column on nm. Depends on which code cycle the house was built under, before the 2011 code 25 amps was ok on #12.

 

[Sparky3141]

As for the A/C unit, it requires at least 25 amps minimum. Table 310.15 (at least back to 2005) has a double asterisk (footnote) that takes you to 240.4(D)

"240.4(D) -- Small Conductors. Unless specifically permitted in
240.4(E) or (G), the overcurrent protection shall not exceed
that required by (D)(1) through (D)(7) after any correction
factors for ambient temperature and number of conductors
have been applied.

240.4(D)(5) 12 AWG Copper. 20 amperes"

Para 240.4(G) leads to Table 240.4(G) for specific conductor applications for "Air-conditioning and refrigeration equipment circuit
conductors that article 440, Parts III, VI" also apply.

As for the aluminum wire: if it were me, and the wire landed on a device anywhere, I'd at least try to ensure tight connections and/or properly splice to copper and reconnect. It has a tendency to loosen up over time with expansion and contraction.l

Protecting the circuit appears to fall under the compliance of Article 440 part III:

"440.22 Application and Selection.
(A) Rating or Setting for Individual Motor-Compressor.
The motor-compressor branch-circuit short-circuit and
ground-fault protective device shall be capable of carrying
the starting current of the motor. A protective device having
a rating or setting not exceeding 175 percent of the motorcompressor
rated-load current or branch-circuit selection
current, whichever is greater, shall be permitted, provided
that, where the protection specified is not sufficient for the
starting current of the motor, the rating or setting shall be
permitted to be increased but shall not exceed 225 percent
of the motor rated-load current or branch-circuit selection
current, whichever is greater."

Which would make the breaker size legal but still doesn't change the ampacity of the "small" wire size rated at 20 amps. I believe this circuit requires at least a number 10. And I've always put these on 30 amp breakers with no problem on a new installation.

 

[norcal]

If it had been 12 AWG THHN/THWN the it would have been fine but NM cable ampacity has to be sized in the 60 degree column (334.80),so 20A max.

 

[kwired]

Hello......

Had a call to check panel for some issues a home inspector brought up for house sale inspection.

Multiple grounds twisted together on panel.

They are. One went to the bar......some grounds are insulated , some not.

I know if the bar is rated for it you can put 2 grounds in one lug if same size conductor.....
Can you splice several grounds together instead and bring one ground to the bar?
There a combination of 12's and14's..........can I make a splice to one twelve and ground it, or is there an article stating all grounds in a panel must terminate on the ground bar?
There all too short to reach the bar.....do I have to install another one to the enclosure closer to where they reach?

AC--

Saw two 12's on a 30 two pole... they went outside to the ac. Not on list of what inspector picked up but for my own head, or if someone wants me to sign off on electrical and not just
invoice for repairs mentioned.
rheem ac at least 10 yrs old

v- 208-230 1 phase
compress rla 18
lra 104
fan 2 hp1/3

max fuse or brk 40
min fuse or brk 30

min. supply circ ampacity 25

the wire is 12-2 nm older........(might be thw)
should I rate that from the 75 degree column at 25 and that is actually correct? the outdoor disconnect is rated for 50a I believe...couldn't tell, it was mucked up alittle...
mabe 30.


There's one 12-2 AL nm wire on a 15a which seems to go to a whole house fan.... should be ok right.
Short of pulling the ladder out to crawl in the attic, seams there would be only two points to question in that circuit, that I could see, is if the switch was al/cu rated and if the motor
had to feed with copper conductors only ???

Thank You

Nothing prohibiting connecting multiple EGC's together as long as the largest size necessary in the group is what is the common lead for the whole group.

NM cable must be sized according to 60 deg C ampacity column, but can use 75 or 90 degree columns for ampacity adjustment purposes. Please note that in 2011 NEC they changed the 60 degree ampacity of 12 AWG to 20 amps, before that it was 25 and your application likely would have been compliant at the time of installation.