Dual main panels with two subpanels - what to do...

[beelsr]

My dad's place has got me scratching my head. He was a builder and while definitely old school, definitely not a sparky. I can handle most stuff inside the house and while I know some of this is wrong, some is beyond me and _I_ know to ask for help, so...

Originally ('90s) a single 200A service fed by direct-buried Southwire 350 kcmil AL USE-2. It's a couple hundred feet from the transformer. The original panel fed one and then two detached structures. More on them later.

In the early '00s the building was duplexed, with the second side getting its own 200A panel. The PoCo specced and ran new wire for this, but it's also 350 kcmil AL in 4" PVC - "General Cable BICC Brand SQ 2005". According to what my dad says, the service cable had to be upgraded when the second main panel was added. It just seems... strange to replace the service with just a different brand of the same size - USE-2 is USE-2, right? Anywho, they split the service in the meter box and it runs separately to both panels from there.

Starting with the new/second main panel since it's in better shape: meter -> disconnect -> panel. There's a disconnect on the inside of the wall and 4/0-4/0-4/0-2/0 AL SER then goes over to the second panel. I did note the bare cables cut-off in the meter box. Which was a real "I coulda hadda V8" moment. The 2/0 bare cable from the SER feeder connects from the second panel to the disconnect and from the disconnect goes... no where. The disconnect is bonded back to the original panel's ground lug with two #8 wires. There is a #8 bare wire run down from the second panel with the SER and this GEC connects to the single ground rod that was installed with this second panel. Which just seems... wrong to run the ground through a #8 when there's a 2/0 sitting there doing... nothing. The panel has the N-G bond strap installed under the main lugs and feeds no subpanels.


Moving back to the original panel. It has no N-G bonding strap installed. And I don't think it ever did because it was sitting on the bottom of the panel, covered in 25+ years of dust. The GEC for this panel goes through the BX down through the slab and then to a single completely buried ground rod. The cut-off bare wire from the meter box for this panel ends 1/2" inside the panel.

The first subpanel is an outbuilding a little over 100 feet away from the service entrance. It's a 4 wire feed in PVC conduit, fed from a 100A breaker. Nice that he ran a 4 wire all those years ago. This subpanel has the N-G bond installed. No ground rods - bedrock is maybe 2' below grade.

The second subpanel is the detached garage, 40 feet away. It's a 4 wire feed in PVC, fed from a 100A breaker into a 100A breaker as the disconnect. This panel has N-G bonded via a 12/14ga wire through bottom positions on the bars. N&G cables are run like in a main panel where they're indiscriminately connected to the bonded N&G bars. {OCD attack} Yes, I see doubled neutrals under a single screw. And the variety of brands of breakers. The breaker with the temporary run for the air compressor has already been re-done (Hey, there's a cover for a reason...). And of course, no ground rods (bedrock, again), nor a UFER when he poured the slab (sigh).

And at some point in the last 5,6,7 years, he installed Eaton whole-house surge protectors in all four panels.

What I think needs to be done:
1. for the original panel:
install N-G bonding strap
extend and re-route the G cable for the suppressor around the breakers, not across them. But couldn't I just screw the N&G wires down next to each other since N-G will be bonded in this panel?
2. for the outbuilding subpanel:
de-bond N&G
ground rods
3. for the garage subpanel:
de-bond N&G
ground rods
either:
a. re-route branch circuits in the panel to split N & G wires
need more holes so get add-on bars for each side and nut a pigtail for the wire that needs to move to the other side
b. get a new panel
for ease of wiring each branch down a single side of the panel
so the breakers in the panel are all actually listed to be in the panel

What I'm unsure about:
1. for the second main panel: replace the #8 with a new GEC (size?) from the disconnect to the ground rod. Or does the disconnect cause it to fail the "continuous to the first rod" requirement?
2. Do I need to add a second ground rod for either (both) of the main panels (same building but electrically separate) or is the two ground rod thing only for detached structures? Or bond the single ground rods for the two main panels together? Or are they already bonded enough together through the disconnect's pair of #8s?

 

[wyliesdiesels]

wow you posted a lot such a huge mess. someone obviously didnt know what they were doing....

give me some time to digest everything you have here...

 

[wyliesdiesels]

.....I did note the bare cables cut-off in the meter box. Which was a real "I coulda hadda V8" moment. The 2/0 bare cable from the SER feeder connects from the second panel to the disconnect and from the disconnect goes... no where.

ok, so the SER from the meter to the first means of disconnect (left in pic 2), for what i will call "unit 1" and from meter to main service panel (right in pic 2) for "unit 2", is 4-wire, and a waste of money, since the EGC/bare ground is not needed. this is why it was cut off. Only 3 wire SEU is needed between meter and the first means of disconnect or a main service panel.

Past the first means of disconnect (on left) or main service panel (on the right), 4-wire SER is needed.

My guess is someone didnt want to buy 2 different types of SE cable so they bought the 4-wire SER. no harm done, other than to their wallet.

Now, we have bigger issues here as it looks like all the panels past the first means of disconnect or main service panel, which are considered SUBPANELS, must have a 4-wire feeder AND an isolated neutral. In every picture you posted it looks like the neutral bar is bonded and the EGC goes to the neutral bar. This is a BIG NO NO!

As to "coulda had a V8" not sure what you meant by that. There is nothing gained in having an intact EGC ran to the meter pan.

 

[wyliesdiesels]

The disconnect is bonded back to the original panel's ground lug with two #8 wires. There is a #8 bare wire run down from the second panel with the SER and this GEC connects to the single ground rod that was installed with this second panel. Which just seems... wrong to run the ground through a #8 when there's a 2/0 sitting there doing... nothing.

The disconnect for unit 1 should go from the bonded neutral bar to the rod NOT to the main service panel for unit 2.

The second panel with bare #8 is a subpanel and doesnt need a connection to a grounding electrode. you can remove this.

The bare 2/0 should be doing something. it should be connected to the neutral bar in the disconnect for unit 1 or the main service panel for unit 2, whicher one the SER goes to

 

[wyliesdiesels]

Starting with the new/second main panel since it's in better shape: meter -> disconnect -> panel. There's a disconnect on the inside of the wall and 4/0-4/0-4/0-2/0 AL SER then goes over to the second panel.

The top right pic is NOT a main panel (you labeled it "second main panel") since there is a disconnect ahead of it and should not be called main panel cause it adds confusion. It is a subpanel and MUST have an isolated neutral bar and separate ground bar.

the disconnect is the first means of disconnect and should have a bonded neutral bar which it doesnt look like it does.

 

[wyliesdiesels]

in the "second subpanel" pic the neutral bar is bonded and this is a no no. you need to remove the bonding strip, add 2 ground bars, and move the grounds over to the new bars. also those green ground wires, if they go to the ground rod, are unnecessary and should be removed.

 

[wyliesdiesels]

Moving back to the original panel. It has no N-G bonding strap installed. And I don't think it ever did because it was sitting on the bottom of the panel, covered in 25+ years of dust. The GEC for this panel goes through the BX down through the slab and then to a single completely buried ground rod. The cut-off bare wire from the meter box for this panel ends 1/2" inside the panel.

The neutral bar needs to be bonded here since this is a main service panel.

The bare EGC that is cut is not needed....

 

[wyliesdiesels]

The first subpanel is an outbuilding a little over 100 feet away from the service entrance. It's a 4 wire feed in PVC conduit, fed from a 100A breaker. Nice that he ran a 4 wire all those years ago. This subpanel has the N-G bond installed. No ground rods - bedrock is maybe 2' below grade.

The neutral bond needs to be removed, ground bar added and all grounds need to be moved over to the new bar(s).

also 2 ground rods are needed here

if this was done prior to 2008, then 3-wire with bonded neutral and rods, wouldve been code if no other parallel metallic pathways...

but since its 4-wire already, switch it

 

[wyliesdiesels]

The second subpanel is the detached garage, 40 feet away. It's a 4 wire feed in PVC, fed from a 100A breaker into a 100A breaker as the disconnect. This panel has N-G bonded via a 12/14ga wire through bottom positions on the bars. N&G cables are run like in a main panel where they're indiscriminately connected to the bonded N&G bars. {OCD attack} Yes, I see doubled neutrals under a single screw. And the variety of brands of breakers. The breaker with the temporary run for the air compressor has already been re-done (Hey, there's a cover for a reason...). And of course, no ground rods (bedrock, again), nor a UFER when he poured the slab (sigh).

same issue with this subpanel as the one i just commented about above.

Neutral bond needs to be removed, new ground bars added and grounds moved over to new bar(s). grounding electrodes also needed.

mismatched breakers should be changed as well

 

[wyliesdiesels]

And at some point in the last 5,6,7 years, he installed Eaton whole-house surge protectors in all four panels.

nothing wrong with that...

 

[wyliesdiesels]

What I think needs to be done:

1. for the original panel:
install N-G bonding strap
extend and re-route the G cable for the suppressor around the breakers, not across them. But couldn't I just screw the N&G wires down next to each other since N-G will be bonded in this panel?
2. for the outbuilding subpanel:
de-bond N&G
ground rods
3. for the garage subpanel:
de-bond N&G
ground rods
either:
a. re-route branch circuits in the panel to split N & G wires
need more holes so get add-on bars for each side and nut a pigtail for the wire that needs to move to the other side
b. get a new panel
for ease of wiring each branch down a single side of the panel
so the breakers in the panel are all actually listed to be in the panel

sounds good so far. if you need more holes for neutrals, it may be difficult unless you can find listed parts. ground wires can be doubled up

 

[wyliesdiesels]

What I'm unsure about:

1. for the second main panel: replace the #8 with a new GEC (size?) from the disconnect to the ground rod. Or does the disconnect cause it to fail the "continuous to the first rod" requirement?
2. Do I need to add a second ground rod for either (both) of the main panels (same building but electrically separate) or is the two ground rod thing only for detached structures? Or bond the single ground rods for the two main panels together? Or are they already bonded enough together through the disconnect's pair of #8s?

#1 this is NOT a main panel. It is a subpanel and needs to be configured as such.

It also doesnt need a GEC since its in the same building as the first means of disconnect. The GEC needs to go to this disconnect's bonded neutral bar. bare solid #6 cu will work.

#2 2 rods were not originally required but it would hurt to add a second. If you do add a second rod, I would run 2 separate single pieces of bare #6 cu- one from the disconnect through the first rod and on to the second.

Do the same for the main service panel....

Remove the GECs from the subpanels...

Hopefully, all my comments were clear as mudd and i covered everything....

 

[beelsr]

I think in my desire to be clearer, I was still unclear... There are two main panels.

If you look at the meter picture in post 1, there are two conduits going through the wall.

The left-side conduit (looking from the outside) feeds directly into what I'm calling the original main panel (you're calling unit 2), because it was the first panel installed. On the second pic in post 1 (inside view), it's the pair of LBs that go into the panel, directly downstream of the meter. There is no disconnect for this panel.

From the outside, the right-side conduit feeds from the meter to the disconnect. Which then goes straight up into the truss-space and over to what I'm calling the second main panel (unit 1) because it was installed 10 years later. The feeder between the disco and the panel is SER and the bare #8 zip tied to the feeder.

Here's a quick drawing. Orange is the original install and blue added when the building was duplexed.

Less muddy?

edit: i started typing this before you were done with all your posts. Took me a while to do my awesome drawing... I'll read the rest and be back in a bit. Shower-time...

 

[wyliesdiesels]

I think in my desire to be clearer, I was still unclear... There are two main panels.

no you were clear and there isnt 2 main panels. I explained previously but read below

If you look at the meter picture in post 1, there are two conduits going through the wall.

The left-side conduit (looking from the outside) feeds directly into what I'm calling the original main panel (you're calling unit 2), because it was the first panel installed. On the second pic in post 1 (inside view), it's the pair of LBs that go into the panel, directly downstream of the meter. There is no disconnect for this panel.

yes this is a main service panel since there is no disconnect ahead of it but....

From the outside, the right-side conduit feeds from the meter to the disconnect. Which then goes straight up into the truss-space and over to what I'm calling the second main panel (unit 1) because it was installed 10 years later. The feeder between the disco and the panel is SER and the bare #8 zip tied to the feeder.

what youre calling "the second main panel" is most definitely NOT a main panel due to the DISCONNECT ahead of it. This i explained in at least one of my previous comments.

The first means of disconnect is the main service regardless if its one breaker or a panel full of breakers.

This DISCONNECT is where the neutral needs to be bonded. ALL panels after it are SUBPANELS and thus need a 4-wire feeder AND ISOLATED neutral bar(s)....

The bare #8 for the GEC is a waste. Subpanels in the same structure as a main service panel or feeder subpanel DO NOT need a GEC or connection to rods.

So the main disconnect needs to have a GEC ran to it

you should also run bond wires from plumbing, such as water and gas to both the disconnect and main panel.

 

[wyliesdiesels]

And what you have now with bonded neutrals in multiple locations creates a very dangerous shock potential hazard.... neutral return current could and will flow on any pathways possible.

need to make sure there are only TWO neutral bonds on the entire system- one in the disconnect, the other in the main panel next to the disconnect AND NO WHERE ELSE.

 

[beelsr]

no you were clear and there isnt 2 main panels. I explained previously but read below

The first means of disconnect is the main service regardless if its one breaker or a panel full of breakers.

This DISCONNECT is where the neutral needs to be bonded. ALL panels after it are SUBPANELS and thus need a 4-wire feeder AND ISOLATED neutral bar(s)....

And now that makes sense and I'll re-read everything again. Starting with your edit of your first reply...

 

[beelsr]

...since the EGC/bare ground is not needed. this is why it was cut off. Only 3 wire SEU is needed between meter and the first means of disconnect or a main service panel...

Ahh, I get it. Now it makes sense.

Past the first means of disconnect (on left) or main service panel (on the right), 4-wire SER is needed.

Because past that point, they're all sub-panels. Duh...

Now, we have bigger issues here as it looks like all the panels past the first means of disconnect or main service panel, which are considered SUBPANELS, must have a 4-wire feeder AND an isolated neutral. In every picture you posted it looks like the neutral bar is bonded and the EGC goes to the neutral bar. This is a BIG NO NO!

Yep. All N-G bond decisions were made incorrectly, right? Wrong kind of perfection, here...

The disconnect for unit 1 should go from the bonded neutral bar to the rod NOT to the main service panel for unit 2.
The second panel with bare #8 is a subpanel and doesnt need a connection to a grounding electrode. you can remove this.
The bare 2/0 should be doing something. it should be connected to the neutral bar in the disconnect for unit 1 or the main service panel for unit 2, whicher one the SER goes to

the disconnect is the first means of disconnect and should have a bonded neutral bar which it doesnt look like it does.

Now that makes sense. The GEC for the disconnect to affect the required N-G bonding can be connected on either the line side or load side since the neutral is passed through and un-switched on the disconnect, right? #6 to the ground rod, uninterrupted. Lucky for us, he didn't pound that rod in all the way.

And I should remove the 2 bonding wires on the disconnect into unit 2's main service panel?

also those green ground wires, if they go to the ground rod, are unnecessary and should be removed.

that's just the grounding wire for the eaton surge suppressor.

... #2 2 rods were not originally required but it would hurt to add a second. If you do add a second rod,
I would run 2 separate single pieces of bare #6 cu- one from the disconnect through the first rod and on to the second.
Do the same for the main service panel....

"wouldn't" hurt ?
and just to make sure I get what you mean about the 2 separate single pieces of bare #6. Do you mean run a single #6 for the pair of rods for the disco and saving an acorn on the first rod? and then do the same for the original main panel? Do you mean to run both to the same pair of rods or separate rods?

Hopefully, all my comments were clear as mudd and i covered everything....

I'll give you a passing grade.

I caught most of what needed to be done (more than the inspector who passed all this) except the whole disco-subpanel thing (which got passed as well) threw me for a loop. Which is why I asked here, I knew you'd know.

Do you have an opinion about the replacing of the 350 kcmil service with the same-sized wire?

 

[wyliesdiesels]

Yep. All N-G bond decisions were made incorrectly, right? Wrong kind of perfection, here...

yes any bonded neutral buss past the main is wrong...

Now that makes sense. The GEC for the disconnect to affect the required N-G bonding can be connected on either the line side or load side since the neutral is passed through and un-switched on the disconnect, right? #6 to the ground rod, uninterrupted. Lucky for us, he didn't pound that rod in all the way.

And I should remove the 2 bonding wires on the disconnect into unit 2's main service panel?

Havent seen the inside of the disconnect. does it have a neutral bar?

yes remove the bond wires between the disco and main service panel.

Where are the water line and gas line bonding wires?

"wouldn't" hurt ?
and just to make sure I get what you mean about the 2 separate single pieces of bare #6. Do you mean run a single #6 for the pair of rods for the disco and saving an acorn on the first rod? and then do the same for the original main panel? Do you mean to run both to the same pair of rods or separate rods?

yes run one single piece of #6 from disco to first rod, loop through then on to second

do the same for the main service panel.

you can use the same rods btw

Do you have an opinion about the replacing of the 350 kcmil service with the same-sized wire?

Its strange. dont see any reason to do so unless the original was damaged some how.

 

[beelsr]

Havent seen the inside of the disconnect. does it have a neutral bar?
...
Where are the water line and gas line bonding wires?

I believe so. The bar runs through the middle and has 4 extra terminals.
The disco is in the second picture. It's a SquareD Circuit Breaker Enclosure QOM22225NS. Here's a tech sheet on it - https://images.tradeservice.com/9ETBOIYK8205G6UU/ATTACHMENTS/DIR100250/SCHNDRE07424_1_39.pdf


Water and propane are bonded off-picture. You can barely see the phone lines bonded to the AC cable coming down the left side of the main service panel (clamp with yellow hang tag). Copper airlines in the garage will be bonded when they get finished.

 

[beelsr]

I went to HD today and found another disconnect on the shelf. Popped open the box and scanned the installation docs. They ship with the regular green bonding screw so I think I'm good.

Thanks for your help, Wylie!


Next up: trying to convince him that it would be better to convert his dozen or so welder/plasma plugs/outlets/cordage from 10-50 to 6-50 instead of just moving the 3rd conductor in the panel from the N to the G buss on the 2 or 3 breakers. His first welder was this 1960's buzzbox and everything since has been adapted to that 'standard'. I'm sure it's been done but I'm also just as sure it's not legit.