Thanks for reading this llloooooonnng post! Love to get the same answers more than once!
I want to install a transfer sub-panel for emerg. Back-up from a 5550 gen.

I am finding what I believe are issues with my house wiring, however. Outside I have a 200A main breaker in weather-tite panel that the POCO insisted upon when I built a carport and moved original service weatherhead. The move was just about 4 ft, but around a corner so no wires would be over the carport roof. The meter pan is just beside the outside box (call it Main).

I also have the original 200A panel recessed into a kitchen wall (call it Sub) that is fed from the outside Main and accessed only from inside the house. The service has always been grounded via the meter pan to 1 rod.

Trouble starts here! When I installed the outside box (Main) for exterior access by POCO orders, the inside box became a sub-panel. The Whites (N) and Grounds for all house circuits are together on same Gr bar in sub-panel. Granted, it is only a few feet from the Main and fed by 2' metal conduit (carries Ground back to Main), but I'm told it is improper and N needs to be isolated on new insulated bar on inside panel (Sub). It's a bit crowded in there. I want to install a gen xfer switch sub-panel (call it Xfer Sub) and feed interlocked breakers side-by-side 60A from POCO and 30A from genset. Only one breaker can be on. Gen feed will come in via 4-wire 30A awg10.

Neutral will be floating at gen and gr rod in place for gen frame. 4-wire gen cord w. L14-30 twist-loc ends goes to male pronged inlet box. Box is connected via 4-wire awg 10 to xfer sub panel on wall under carport. The 60 A feed from POCO can come from Sub with a 60A double breaker and 6 critical circuits moved from Sub to Xfer Sub. (water well, refrig, TV, a few lights). I am told that N and Gr must be separated in Sub and only bonded in main.

So questions... no drum roll needed... Once Neutrals are isolated in Sub, do I need a Ground wire from Sub ground bar (where all bare wires are located) back to Main or is 2" metal conduit enough? If so, what size? Or, do I put a ground rod down just for Sub? Or do I tie in to same Ground rod as meter pan 3 ft away? Main has no ground rod connection but meter pan sits just beside it and it is connected to ground rod.

When I feed xfer switch breakers from gen, 2 hots come in on 30A breaker. Do Neutral and ground go to Sub? Re: POCO feed, only two hots #6need enter xfer sub panel from Sub. Load side of breakers splice back into Sub to feed the house wiring that is in place. Thus, current is supplied to those house wires whether from Sub feed (POCO source) or from genset vis 30A breaker. So, two #6s into xfer sub, two #10 into sub feeding bus bar alternately. Six wires leaving Xfer sub from relocated breakers to feed Sub (well and house circuits).

Along with two hot #10 from gen, a neutral pass-thru isolated and tied into neutral bar in Sub as well as bare ground to grounding bar or green screw on box. Since this Xfer sub is in platic flex conduit, a bare gr shall be carried through to ground bar in Sub. I am attching diagram that seems well marked but please check over carefully and critique as needed for Safety. All of this eqpt is so close together but is metal conduit enough of a ground? Thanks so much for your patient review of this.

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Did you do this yourself or did you have a licensed electrician do this set up for you? If you had an electrician, I would strongly suggest that he come back and rework this project so you don't accidentally burn your house to the ground or worse yet, fry the home when you fire up the generator. If done incorrectly a generator will definitely fry your home's wiring and you could easily ruin a lot of 'spensive stuff you'd not want ruined.

I had to edit your post to make easier to read, try using more paragraphs next time.

I will extract questions or issues and comment after each.


When I installed the outside box (Main) for exterior access by POCO orders, the inside box became a sub-panel.

Correct.


The Whites (N) and Grounds for all house circuits are together on same Gr bar in sub-panel.

Not allowed after the Main Disconnecting Means, so the installation was not done to Code and should have not passed inspection ,nor been connected until wired properly.


Granted, it is only a few feet from the Main and fed by 2' metal conduit (carries Ground back to Main),

Makes no difference.


but I'm told it is improper and N needs to be isolated on new insulated bar on inside panel (Sub).

Correct.

It's a bit crowded in there.

Too bad, it needs to get fixed.

I want to install a gen xfer switch sub-panel (call it Xfer Sub) and feed interlocked breakers side-by-side 60A from POCO and 30A from genset. Only one breaker can be on. Gen feed will come in via 4-wire 30A awg10.

Ok, seems fine so far.

Neutral will be floating at gen

What does that mean?

and gr rod in place for gen frame.

Does the manufacturer require frame to be grounded with a rod?

4-wire gen cord w. L14-30 twist-loc ends goes to male pronged inlet box. Box is connected via 4-wire awg 10 to xfer sub panel on wall under carport. The 60 A feed from POCO can come from Sub with a 60A double breaker and 6 critical circuits moved from Sub to Xfer Sub. (water well, refrig, tv, a few lights).

Ok, again fine so far.

I am told that N and Gr must be separated in Sub and only bonded in main.

Correct.

Once Neutrals are isolated in Sub, do I need a Ground wire from Sub ground bar (where all bare wires are located) back to Main or is 2" metal conduit enough?

Metal conduit is allowed to act as an equipment ground. Not done by quality electricians any longer. You rely on the locknuts for grounding continuity, most people do not know how to tighten locknuts properly.


If so, what size?

60 Amp feeder needs a #6 Cu equipment grounding conductor.

Or, do I put a ground rod down just for Sub?

Never drive a lone ground rod for one piece of equipment.


Or do I tie in to same Ground rod as meter pan 3 ft away?

No shortcuts allowed here.

Breakdown and run equipment grounding conductors.


Main has no ground rod connection but meter pan sits just beside it and it is connected to ground rod.

Exactly perfectly fine. Grounding can happen at the Main Disconnecting Means or at the meter

When I feed xfer switch breakers from gen, 2 hots come in on 30A breaker. Do Neutral and ground go to Sub?

Yes, and separated in here too.

Re: POCO feed, only two hots #6need enter xfer sub panel from Sub. Load side of breakers splice back into Sub to feed the house wiring that is in place. Thus, current is supplied to those house wires whether from Sub feed (POCO source) or from genset vis 30A breaker. So, two #6s into xfer sub, two #10 into sub feeding bus bar alternately. Six wires leaving Xfer sub from relocated breakers to feed Sub (well and house circuits).

Neutrals should always be run with the line conductors.

Along with two hot #10 from gen, a neutral pass-thru isolated and tied into neutral bar in Sub as well as bare ground to grounding bar or green screw on box. Since this Xfer sub is in platic flex conduit, a bare gr shall be carried thru to ground bar in Sub.

Seems OK.

I am attching diagram that seems well marked but please check over carefully and critique as needed for Safety.

Make the corrections I noted.

All of this eqpt is so close together but is metal conduit enough of a ground?

Again, see my comment above on equipment grounding and use of conduit

Thanks so much for your patient review of this.

I will have more patience if you list your questions and not ramble on and embed them in the narrative.

Thanks again for the review. I am finding flaws and correcting them with your help. The shed project completed last week made that a safer job. Luckily, no incidents all these 28 yrs. Certainly do not want to start any now!

Usually, you don't add a neutral bar. You add a ground bar and remove the green neutral bonding screw in the sub panel. Usually ground bar kits are available for the panel.

Tk:

Nice job. At least you have the power to clean the post up.

A ground rod is required when the genset is hard wired to the house.

If a cord will be used to connect to the transfer panel then no ground rod is required or needed.

There will be some of both since I intend to use a cord from genset to power inlet box, then hard wire to xfer panel. I will carry EGC through both then into the Sub. OK?

I'll need to check and see by moving some of the spaghetti and looking for the bond. I only called it a grounding bar because all the bare wires were on it, as well. I do know it is multi-tiered and in a forty space 200A GE box about 28 yrs old (diagram below). Thanks for the input, KISS!

If this is a portable generator how are you going to hard wire it? There are usually no provisions for that.

One of these help?:
Generator InterLock Kit - General Electric Kits
And
http://www.interlockkit.com/index.htm

There's plans for an extension cord (10-3 w Gr stranded outdoor cord with L14-30A molded ends)from gen set to power inlet box mounted on house under carport. Power inlet box (male inlet L14-30) is hard wired ( 10-3wGr in plastic conduit out of harm's way under the house, house is on block chain wall with limited access) to xfer switch box 30 ft away. That's what I mean by both extension and hard wire.

In attempting to understand both what to do and why?? I am puzzled about the size of the grounding conductor to tie the inside sub with all my house breakers back to the Main (outside box with pass-thru from meter pan). If....... The reason for one bonding point for Neutral to Ground is to assure one and only one "road home" for stray electricity.

In the event of a failure of the Neutral conductor providing current into my inside Sub, should not the grounding cable be a large cable to handle the high amperage?

I intend to install a ground bar and isolate Neutral from Ground, but the three cables feeding this interior box are huge. (Whatever usually provides 200A service). 2/0? I do not know for sure. But, once ground is isolate from Neutral the huge Neutral is handling that end but should not the Ground be very large back to the outside main?

Thanks for your interest in my project!

<Cleaned up - KISS>

Your allowed to reduce the size of the ground conductor because it only handles fault currents.

The neutral/ground bonding provides a single point reference for your home.

Thanks for reading my post. These kits are a good idea and under strong consideration. I simply do not have the 3 spaces in my inside box to put the gen backfeed breaker it would require. Therefore, the gen xfer sub panel is my next best option. I found a guy building them with GE components where I can use existing breakers. I even have a double 30A left from when I corrected my shed wiring last week.
Thanks, curlie.

How about a couple of tandem breakers. Two breakers in one space to free up some spaces.

Circuit Breakers - Tandem Breakers

I have a 200A breaker box that used to be a Main and became a Sub panel when an oudoor box was installed ahead of it to "feed-thru" and provide an outside means of disconnect, at the insistence of the Power Company. I have recently learned that this arrangement is not code-compliant since all of the Neutrals and Grounds were on the same bar in what is now the sub-panel and that this must be corrected. I am told that the 3" metal conduit is not an ideal ground connector back to the main since many people do not know how to properly tighten the locknuts where the connection is made and that quality electricians do not rely on that. Since the Sub has a large amp draw potential with all the house breakers in it and the 200A feeds hot, hot and Neutral come into this sub-panel, what size conductor would be appropriate to physically wire the ground back to the main about 4 ft away?

I merged these two posts as they are related.

Note: EGC stands for Equipment Grounding Conductor.

Earlier post I said #6 EGC for a 60 amp feeder, got confused between the 60 amp sub feeder and 200 amp service feeder, since your list of questions was confusing.

So correction is,

The 60 amp feeder needs a #10 EGC, and to answer your last post, a 200 amp feeder needs a min of #6 EGC.

I am not going to get upset that I told you a size too big. Neither should you.

If the metal conduit is intact, wrench tight, and attached firmly to the boxes at both ends tightly with double locknuts, one in and one outside, as I stated, metal conduit is allowed as an EGC.

Since you're a layperson, my advice was to be overly cautious.

If you can be sure the conduit is installed properly, then use it as an EGC. To be absolutely sure there is no problem, install the supplemental EGC, and not worry about it.

Keep in mind, when I answer one question, I keep in mind many others may read this, and I offer advice as best I can to cover other installations, and not get into too much detail of exceptions, etc.

Also, earlier Stan was, I believe, questioning the "hardwire" aspect of the genset.

Cord cannot be used permenently from the genset to the junction box on the wall. If you plug in a cord into a receptacle or inlet, then fine, but do not hardwire cord.

This thread bounces around so much, I am sure I am missing something.

I am interested in "the guy building something out of GE components". Is this a NEMA manufacturer making UL listed products, or a guy in a home shop on his own building something NOT UL Listed. Something about this is scary.

With your Transfer panel, it should allow you to choose either POCO power or Generator Power, backfeeding isn't a problem, Does your Transfer Panel allow that or are they just breakers?
Personally I like The Interlockkit, as you don't need to add the transfer panel, You can select ANY circuits instead of the selected six.
It only needs a double pole Breaker in the Top right position.
Plus the transfer panel is usually more than the interlockkit.
Can do more for less.
If your transfer panel has the ability to select one or the other, an Interlockkit won't be necessary.

KISS and Stratmando,
Yes, the transfer panel has breakers tied mechanically where one must choose POCO or gen and both closed is not an option.

Interlock Kit K-8110 matches my panels breaker config. It says it requires 3 panel spaces, so I am inferring 3 full size spaces. I am a bit cautious of half-size breakers on the 240V connections, although I do have one in place already on my central unit's blower motor; it is a slimline double 30A requiring one full space. I have all half-space breakers on the lighting and outlet circuits, but do have a couple of places I might be able to down-size. As I said, I'm a bit cautious about the higher voltage tandems, whether or not I have a good reason. I currently have two open half-spaces in the entire box. Additionally, I have double full-size breakers at 50A for the range, 60A for the central AC/Heat, 30A for the clothes dryer, and here could be my target - a full double 20A for the water well and a full double 30A for the clothes dryer. Downsizing the last two would yield 2 full (4 half) spaces in addition to the two half spaces currently available. With a bit of rearranging (while moving those grounding conductors) I could free up enough space to use an Interlock Kit. This would provide the additional benefit of using my shed as a sentry, since it's power comes from the outside "Main" panel.

TK - I understand your position re: quality of craftsmanship on putting these GE boxes together. It seems that both Square D Kit # PK4DTIM4LA and GE are selling the parts to add to panels as well as the panels with tied breakers. One can choose an inside or an outside panel. Square D sells the parts for their QO panels or they will sell you one already assembled in either inside or outside enclosures if you do not already have the panels. They come in a choice of mains 100, 125, 200 also.
I would guess that any of these aftermarket assemblies are not considered "tested" since they are not factory assembled. The reason I would choose GE is that I could use breakers I already have and I am able to choose a 60A POCO/ 30A gen feed breaker pair. GE sells a box already assembled and provides 60A /60A tied breaker pair. ???Would that be OK to use since overload protection on gen set is a 30A breaker??

THANKS! To TK, KISS, Stan, and all. I found that Murray made a rocker-type device that shuts off one breaker when the other is turned on. Therefore, I used a weathertite sub-panel outside under my carport and moved the desired circuits (for use in emergency) into it. Had to buy new breakers, but did not want to put GE breakers from inside into the Murray panel. In summary, bought a GE inlet box that is weather-tight and mounted under carport not far from where genset sits. Bought a name-brand power cord with sealed ends (rather than make one up where male and female ends are not sealed), installed a toggle switch for genset bonding wire and marked positions for use as portable (bonded to frame) or not. Ran 10-4 wire to sub-panel near front of carport (30 ft run) and used rocker bracket for interlocked breakers. The house backfeed is 60A whereas the gen breaker is 30A; only one can be on at a time because of mechanical barrier. Also, thanks to expert advice from TK and others, added a grounding bart to inside panel and moved all the grounds to it, and tied it back to "Main" panel outside with #6 copper green. Therefore, separated gr from neutral in both sub-panels. The new box (8-16 circuits) by Murray was $35, interlock bracket $30, new breakers $60 includes the double 60A needed from inside to backfeed the outside sub. A little more trouble than the interlock kit, but by weight, a much heftier purchase. All kidding aside, the Interlock Kit would have demanded three spaces inside that I did not have. This set up freed up space inside in case of any future needs. Again guys, you rock! And are excellent teachers!