Best route to run feeders from ATS back to main panel

R

RBrown504

Member
Location
Louisiana
Occupation
I & E Tech
I'm having trouble deciding the cleanest/best way to run the feeders from a soon to be installed ATS back to my main panel that is directly behind the meter base recessed in the garage wall.
https://imgur.com/a/lz3NFrq

ATS is 10 inches shorter than the main panel. I was originally was going to nipple out the side of the ATS and LB into the top back of the panel but that's not really an option in regards to where the available knockout is.

I was thinking of using an LR out the bottom of the ATS and then an LB into the wall under the Meter/MDP and putting a trough/pull box below the main panel. But I can't find any that have an oversized flush cover as this is a finished and painted garage wall.

Any thoughts on the best way to do it?
 
2023 NEC

Why can't you nipple out of the right side of the meter base and into your ATS then refeed the existing interior panel from the ATS.?
Maybe with some flex.

Then you'll have to run PVC to the generator from the exterior ATS.
Remember the ATS is rated for service (check the ATS label) so you'll have to properly size the GEC (grounding electrode conductor) per the SE conductors, if necessary.

A disconnect will be required at the generator. No ground rod there at the generator.

The 2023 NEC requires an exterior disconnect for first responders.

So, you may have to totally redesign everything, and work around that.

Section 230.82 and 230.85 (A) (1) (2) (3) and (B) (1)(2)(3) provides additional info.

230.85 (E) (1) and (1) (2)and (3)) and (2) Marking Location and Size.

The ATS might be suitable as a disconnect for emergency disconnecting.
Check with your AHJ.

It must have a short circuit rating equal or greater than the emergency disconnect.

Thanks for reading.
Comments accepted.
TX+MASTER #4544
 
I'm not sure if my photos posted or not. Wasn't sure how to add photos to my post showing the setup. If they have not, please let me know.

I am going to nipple out the right side of the meter to the ATS. Run conduit underground to the generator (~150' with 3 #2 and 1 #4). My concern was how to feed the main panel from the ATS.

Is flex suitable for exterior penetration and hidden behind sheetrock?

We are currently under 2020 NEC and the ATS has a 200 Amp breaker for disconnect. It's a Generac RXSW200A3.

My inspector told me not to bond my neutral in the ATS like we normally would, the POCO wants it bonded in the meter base itself. Which is odd that it's already bonded in the meter and no EGC enters the main panel from the meter or even a GEC from the ground rod.
 
2023 NEC

Hey,RBrown504,
Why can't you exit the ATS on its left side and expose some PVC or something else found in 230.43 (1) thru (19), and go in the back of your inside panel enclosure? Here's where you will need an EGC.

You will need an EGC conductor run with the feeder conductors, you're now a feeder on the load side of the CB.
Your grounding electrode conductor is not an (EGC ) check the definition of it, will terminate in the ATS with your neutral conductor.

You never need an EGC from the meter base to your Main Circuit breaker; there's no place to terminate it, because the neutral conductor will see any fault on the line side and return it back to the source. Then on the load side is when you will most likely need it.

The inspector is right because the generator in this case is not a separately derived service because the neutral will be switched in the ATS.
Who is or what is POCO, I'm assuming it's the local electrical utility company.

The meter base is bonded as it always is with your neutral and the service entrance neutral and no EGC.

I'm guessing that they (POCO) want a grounding electrode conductor from the meter base connected to the ground rod.

That is somewhat unorthodox here in great state of Texas except in some rural areas

Here's what 2023 NEC says: Section 250.24 (A)and (1), "........on the load end of the overhead service conductors........" where you have a choice of three possible connection points.

Section 445.18 (A) and 445.19(C) requires an emergency shutdown for first responders, 2023 NEC.

Do you have a Louisiana electrical license and is it equal to a masters or journeyman's license?
If not you need to get someone who is. Have the AHJ to inspect this job and make sure it is Code compliant.

Thanks for reading.
Comments accepted.
TX+MASTER#4544
 
I suggest placing the ATS like you show it, put an LB pointing up on the right, opposite the nipple, PVC up and over the meter with an elbow, second LB into available top knockout.
 
LarryFine said:
Basically , what I did here, except mirror image.

View attachment 2570846
Click to expand...
How would you suggest connecting the LB through around ~1" of siding to the main panel? A close nipple with a locknut and bushing in the panel?

With it being in EMT or RMC and being in a state that can get slightly above 100 degrees in the summer would I have to derate?

Sorry it took so long to reply. I ended up getting super busy.
 
TX+ MASTER#4544 said:
The inspector is right because the generator in this case is not a separately derived service because the neutral will be switched in the ATS.
Who is or what is POCO, I'm assuming it's the local electrical utility company.
Click to expand...
That seems backwards. If you do switch the neutral, then it is a separately derived service. Also, who said the neutral was being switched?
 
TX+ MASTER#4544 said:
You never need an EGC from the meter base to your Main Circuit breaker; there's no place to terminate it, because the neutral conductor will see any fault on the line side and return it back to the source. Then on the load side is when you will most likely need it.
Click to expand...
Technically this isn't true. Had you said rarely instead of never... On occasion you have a service disconnect before a bank of meters. In that case and EGC is required.
 
RBrown504 said:
How would you suggest connecting the LB through around ~1" of siding to the main panel? A close nipple with a locknut and bushing in the panel?

With it being in EMT or RMC and being in a state that can get slightly above 100 degrees in the summer would I have to derate?

Sorry it took so long to reply. I ended up getting super busy.
Click to expand...
What have you done thru today since March 31 when you started the job? Do you still need advice?
 
Little Bill said:
That seems backwards. If you do switch the neutral, then it is a separately derived service. Also, who said the neutral was being switched?
Click to expand...
2023 NEC
Alternate power source, generator.

The existing grounded (neutral) conductor is solidly connected to grounded (neutral) conductor that goes to the generator at the ATS.
When power fails the ATS switches the conductors that go to the generator, the phase(s) and neutral conductor.

It's all done in the ATS enclosure.

So it is not a separately derived system.

Loss of power allows for the 3 pole ATS to automatically switch to the conductors going to the generator.

When power is restored then it reverts to the original normal power system and there is no energized conductors at the generator.
But there is a solid neutral connection at the ATS.

See the I.N. No. 1 at 250.30 and if you have a 2023 NEC Handbook check out Exhibit 250.12 VS 250.13.
Hope this is not confusing.

Note: If the neutral (grounded) conductor does not have a direct connection of the neutral and is switched via the ATS, it is a separately derived system.

Thanks for reading.
Comments accepted.
TX+MASTER #4544
 
RBrown504 said:
My inspector told me not to bond my neutral in the ATS like we normally would, the POCO wants it bonded in the meter base itself. Which is odd that it's already bonded in the meter and no EGC enters the main panel from the meter or even a GEC from the ground rod.
Click to expand...
The inspector is wrong. The neutral is used for bonding on every enclosure up to and including the service disconnect (ATS in this case).
 
TX+ MASTER#4544 said:
2023 NEC
Alternate power source, generator.

The existing grounded (neutral) conductor is solidly connected to grounded (neutral) conductor that goes to the generator at the ATS.
When power fails the ATS switches the conductors that go to the generator, the phase(s) and neutral conductor.

It's all done in the ATS enclosure.

So it is not a separately derived system.

Loss of power allows for the 3 pole ATS to automatically switch to the conductors going to the generator.

When power is restored then it reverts to the original normal power system and there is no energized conductors at the generator.
But there is a solid neutral connection at the ATS.

See the I.N. No. 1 at 250.30 and if you have a 2023 NEC Handbook check out Exhibit 250.12 VS 250.13.
Hope this is not confusing.

Note: If the neutral (grounded) conductor does not have a direct connection of the neutral and is switched via the ATS, it is a separately derived system.

Thanks for reading.
Comments accepted.
TX+MASTER #4544
Click to expand...
I guess AI isnt quite there yet 😂
 
RBrown504 said:
How would you suggest connecting the LB through around ~1" of siding to the main panel? A close nipple with a locknut and bushing in the panel?

With it being in EMT or RMC and being in a state that can get slightly above 100 degrees in the summer would I have to derate?

Sorry it took so long to reply. I ended up getting super busy.
Click to expand...
in addition to what larry suggested, and depending on the room/geometry, some other options are:

1. use a myers hub on top of the ATS and 90 or 45 out of that to an LB and in.
2. Uae a NEMA 3R wireway on top of the ATS and come out of the back of that into the panel.
3. Come out of the side of the ATS with some pipe and an LB and drill a new KO in panel where needed.
4. Cut in a box or wireway behind the ATS, nipple into that, and nipple into the side of the panel.

Regarding your question about the 1" siding, yeah just size up the right size nipple. Depending on how much room you have/dont have, could use a PVC LB with a box adapter into the nose of the LB.
 
TX+ MASTER#4544 said:
2023 NEC
Alternate power source, generator.

The existing grounded (neutral) conductor is solidly connected to grounded (neutral) conductor that goes to the generator at the ATS.
When power fails the ATS switches the conductors that go to the generator, the phase(s) and neutral conductor.

It's all done in the ATS enclosure.

So it is not a separately derived system.

Loss of power allows for the 3 pole ATS to automatically switch to the conductors going to the generator.

When power is restored then it reverts to the original normal power system and there is no energized conductors at the generator.
But there is a solid neutral connection at the ATS.

See the I.N. No. 1 at 250.30 and if you have a 2023 NEC Handbook check out Exhibit 250.12 VS 250.13.
Hope this is not confusing.

Note: If the neutral (grounded) conductor does not have a direct connection of the neutral and is switched via the ATS, it is a separately derived system.

Thanks for reading.
Comments accepted.
TX+MASTER #4544
Click to expand...
No one has said, or shown that the OP's ATS is switching the neutral. That would not be a separately derived system. Most ATS for residential are just 2-pole and do not switch the neutral.
 
electrofelon said:
Or learn how to make your conduits and entries watertight when necessary.
Click to expand...
I've figured out my route that I'm going to take. It's nec compliant. Nothing wrong with it. But not the way I truly want to do it. The way I wanted to do it would take too long to be able to have a disconnect, inspection, and reconnect all in 1 day.

As far as I know, I believe I saw it somewhere in the manual, Generac doesn't warranty the ATS if you make a top penetration.
 
Use a hub and penetrate the ATS in the top left side and shoot over top of the meter and turn into the panel in a drilled hole second siding board up from the meter.
 
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