# Running two 100 amp main panels from a 200 amp service

Greetings!

I live in a rural country area. The electric company will be installing a pole, meter, and 200amp service with disconnect at pole. (It will require 50 foot run of service cable from pole to main load center in mobile).

Currently the double wide has a General Electric 100amp Main Load Center. This is not going to be enough as I plan on changing the gas hotwater heater, the gas cook stove and the gas central heating unit all to electric. There is no more room in the existing load center.

I have another G.E. 100amp main load center. What I want to do if possible is to install a trough and use split bolt connectors and run service wires to each of the main load center thus giving me 200 amps total. I realize I will have use torque according to mfg specs and use an oxidant.

My twofold question is:

1. the SER cable will be rated for 200amp, but when I run feeders from the split bolt connectors can i go down to wire rated for 100amp?

1. Since this will not be a "main" panel / "sub" panel set up, there is no reason to have one box with neutral isolated, it can be bonded - correct?

If I am incorrect, please advise the best possible solution to get 200amp service out of 2 100amp load centers.

Thank you
Martin
In Memory of Our Daughter
Bailey DeLonais Maynard
January 13, 2005 - March 28, 2005
Healing Oklahoma Hearts - Home
S.I.D.S. It's REAL!!

Last edited by mdmaynard; Feb 9, 2007 at 01:52 PM.
Search this Question
 ScottLwood Posts: 19, Reputation: 2 New Member #2 Feb 9, 2007, 04:09 PM
Since your going to all this trouble why not change your panel out to 1 200amp 40 circuit box.
Another alternative is your meter box disconnect should have spare circuits, run two separate lines to each panel box using 100 amp double pole breakers.

Depending on where you live I'm pretty sure you will have to separate grounds and neutrals.

I personally don't agree with using split bolts but I'm no expert
 labman Posts: 10,580, Reputation: 551 Uber Member #3 Feb 9, 2007, 08:40 PM
I will leave most of your questions to our electrical expert. Life is much easier for me now that we have good people to cover areas I was struggling in.

I see no reason to spend about a $100 on another panel, when you already have one if it will meet code. I am mainly posting to suggest you look at at a double throw disconnect. If you have one installed as part of the job, then in a power outage, you could legally connect in a generator.  tkrussell Posts: 9,638, Reputation: 722 Uber Member #4 Feb 10, 2007, 03:35 AM Changing the 100 amp panel out with a 200 amp would be simpler, but what you propose with the trough is fine. Just below the trough you need two 100 amp disconnects thou, before runnning to each of the 100 amp panels. #2-4 wire SER cable can be used to each 100 amp panel. If the trough and 2 100 amp disconnects are outdoors,they must be NEMA 3R rated, Rain-Tight. Grounding the neutral must be done at the 200 amp main disconnect that will be at the meter location. So one or more ground rod (check with local code how many are needed)will connect to the neutral in the main with #4 copper wire. From that point on 4 wire SER cable is needed, as you are aware. Only at the 200 amp main will the neutral and equipment ground connect. At any panel(s) the neutral must be isolated from the equipment ground. Instead of using split bolts,which must be taped well with one layer of rubber tape and one layer of vinyl tape, look for the mechanical lugs that use an allen wrench bolt, and are all insulated. Made by Burndy, Ilsco,Blackburn,NSI. Still must use antioxidant, but can get much better torquing done, and are pre-insulated. I do think changing the panel out, even thou it seems to be a much more difficult job because of dealing with all the existing branch circuit cables, will give you a better, simpler, and less expensive installation.  mdmaynard Posts: 40, Reputation: 1 Junior Member #5 Feb 19, 2007, 10:24 AM Originally Posted by tkrussell Changing the 100 amp panel out with a 200 amp would be simpler, but . . . I appreciate your input and have taken your advice. I purchased G.E.'s 200 amp main load center kit. (came with 10-20amp breakers, 1-30amp. And 1-50amp). I went to a local supplier to purchast the service cable and what I got was 3 wire direct bury cable along with a separate copper cable). The main disconnect/meter is about 45ft from service panel in house. Where I am some what confused on is grounding. When they install the meter there will be a 200amp main disconnect right there under the meter. The 200 amp main load center I purchased also had 200am disconnects (looks like 4 50 amp breakers all connected together when 1 trips they all 4 trip). If I understand correctly the 8' grounding rod should then be at the meter pole, the separate copper wire will run from pole to inside main load center in house. It is as this panel that the ground and the neutral should NOT be bonded together correct? So I will not run a copper wire from the ground to a ground rod at the house since it is grounded at the meter. Please instruct me correctly on this issue. Also with the service cable I purchased, will it need an anti-oxidant and torqued a specific way?  tkrussell Posts: 9,638, Reputation: 722 Uber Member #6 Feb 19, 2007, 10:48 AM Originally Posted by mdmaynard I went to a local supplier to purchast the service cable and what I got was 3 wire direct bury cable along with a seperate copper cable). The forth wire will now be called an equipment grounding conductor from this point on. Any green or bare branch circuit wires will connect to this wire at the panel on a separate equipment grounding bar, not the Main Neutral bar, which is only for white neutral bracnch circuit conductors. Originally Posted by mdmaynard Where I am some what confused on is grounding. When they install the meter there will be a 200amp main disconnect right there under the meter. The 200 amp main load center I purchased also had 200am disconnects (looks like 4 50 amp breakers all connected together when 1 trips they all 4 trip). The 4 pole breaker is actually two 2 pole 100 amp breakers, each side in parallel, for a total of 200 amps per leg. Manufactures are doing this to use up a great deal of 2 pole 100 amp breakers still in inventory, or are less expensive to make that a true full size 200 amp breaker. They work fine. Originally Posted by mdmaynard If I understand correctly the 8' grounding rod should then be at the meter pole, the seperate copper wire will run from pole to inside main load center in house. it is as this panel that the ground and the neutral should NOT be bonded together correct? Exactly correct, the equipment grounding conductor will connect to a separate equipment grounding bar, which must be purchased, and bolted directly to the panel's metal box using machine thread screws. Every panel already has screw holes drill and threaded for this bar. Originally Posted by mdmaynard So I will not run a copper wire from the ground to a ground rod at the house since it is grounded at the meter. Correct, only at the meter/service disconnect will the two main neutrals one from utility and one going to house), the grounding electrode conductor,(GEC to rod), and the equipment grounding conductor(to house) will all connect together, the GEC to the rod or rods, check with local code if more than one is needed. Originally Posted by mdmaynard Please instruct me correctly on this issue. also with the service cable I purchased, will it need an anti-oxidant and torqued a specific way? I have included an aluminum cable's manufacturer's instructions for proper connections. Let me know what you are not sure about.  mdmaynard Posts: 40, Reputation: 1 Junior Member #7 Feb 19, 2007, 12:14 PM Originally Posted by tkrussell The forth wire will now be called an equipment grounding conductor from this point on. Any green or bare branch circuit wires will connect to this wire at the panel on a separate equipment grounding bar, not the Main Neutral bar, which is only for white neutral bracnch circuit conductors. . . Exactly correct, the equipment grounding conductor will connect to a separate equipment grounding bar, which must be purchased, and bolted directly to the panel's metal box using machine thread screws. Every panel already has screw holes drill and threaded for this bar. . . I purchased PowerMark Gold™ Load Center Indoor Main Breaker Load Center 200 amp Main breaker 32 circuit from Lowe's, you can see same panel at this link: 200 Amp Main Single Phase 32 Circuit Panel - TM3220CCU | Wholesale Electrical Supply Company The old panel was set up so that the left bus/bar was for the main neutral the right bus/bar was for the ground (bare/green copper wire's). The left was bonded to the right. The new panel appears to be set up the same in that the left and right are bonded at the bottom by a bar (could be wrong but it appears to be this way). If this is correct why would I need to purchase a separate equipment grounding bar, when I could must remove the bar that bonds the neutral to the ground? Am I missing something (I am sure I am). Am I confusing ground from neutral? On a side note the cable I purchased was 4/0 direct bury and #4 thhn for the equipment ground conductor. I hope I am on right track.  tkrussell Posts: 9,638, Reputation: 722 Uber Member #8 Feb 19, 2007, 01:23 PM Sorry I was working on a question with Square D HomeLine also and got confused. No your right, all you need to do with GE is to remove the jumper bar at the bottom, bond one side with the green screw, that side becomes the equipment ground bar. The side that does not connect to the panel box will be just for the white neutrals.  mdmaynard Posts: 40, Reputation: 1 Junior Member #9 Feb 19, 2007, 01:30 PM Whew! Thanks for the clearifcation :-) I was worried I was all messed up. I appreciate what you guys do here, helping others. In all sincerity I appreicate it very much!  mdmaynard Posts: 40, Reputation: 1 Junior Member #10 Feb 23, 2007, 07:47 AM Argh!! I was running the service wire (#4/0 alu 3-wire; #4 THHN) from the pole to the newly installed 200 amp panel inside the house and I am 15 foot short. The wire makes it just inside the conduit going from the bottom of the panel inside my house. Can I use split bolt connectors or wire splice and just add the 15 feet I am short? Or do I need to scrap the 45' I already (as you cannot return cut wire) and buy 60' of the wire.  tkrussell Posts: 9,638, Reputation: 722 Uber Member #11 Feb 23, 2007, 08:23 AM Sure the wire can be spliced, using a junction box large enough, and either split bolts that get taped with rubber compund (tape) and vinly, or mechanical lugs that are pre-insulated. Why 3 wire cable and a separate ground wire? Should be a 4 wire SER cable, or is this direct burial cable? I am not clear on the exact type of wire/cable you arer using and the method used to get from pole to house. If direct buried, wire needs to be direct burial rated.  mdmaynard Posts: 40, Reputation: 1 Junior Member #12 Feb 23, 2007, 08:33 AM Originally Posted by tkrussell Why 3 wire cable and a separate ground wire? Should be a 4 wire SER cable, or is this direct burial cable?. . . Yes it is direct burial wire. When I told the gentleman at the supply store what I was wanting to do, the 3 wire direct burial (4/0 alu) is what he sold me with separate ground. Here is what I am trying to accomplish. Electric company set a pole/meter with 200amp breaker at pole. I have 200am G.E. main load panel in trailor. I want to run service wire from the pole to the trailor. The wire is direct burial as mentioned above with separate ground wire. From what the supplier told me the 4/0 alu wire can be direct buried but I would have to run the ground (#4 THHN), in some sort of conduit from the pole to the panel in the house. I bought 45' of each based off measurements taken before pole was set. Pole ended up being set in a different location so I need a total of 60' not 45' so I am 15' short on the wire. I hope that explains better the predictament I am in.  tkrussell Posts: 9,638, Reputation: 722 Uber Member #13 Feb 23, 2007, 09:07 AM Check the #4 wire , it should be dual rated stating THHN/THWN, if not then it cannot be used in the conduit. This is not normal running a spearate ground in conduit, but I suppose if you keep the #4/0 cable and the conduit all bundled together as much as possible it will do. The cable sold to you should have been 4 wire URD cable, and sometimes called "trailer" cable, 4 wires=2 #4/0,1 #2/0, and 1 #4 al twisted together ready for direct burual. Where will the splices end up? In the building or in the trench? The wire can be spliced at either location, just need to be careful splicing outdoors in the trench.  mdmaynard Posts: 40, Reputation: 1 Junior Member #14 Feb 23, 2007, 09:15 AM So, would it be better for me to scrap the wire I have and just purchase "trailer" cable. I paid$2.27/ft for the 3-wire, what is the cost difference between the 3-wire and "trailer" cable?

The splice would end up being in the verticle pvc conduit running from the bottom of the panel in the house (trailor is about 6 foot off the ground at this point).

I am confused. I called the supplier I use and he told me they do not carry 4-wire that has 4 wires=2 #4/0,1 #2/0, and 1 #4 al what they have is the 4-wire = (3)4/0 (1)2/0. He told me what people usually do is buy the 3-wire 4/0 and run separate #4 ground.

 tkrussell Posts: 9,638, Reputation: 722 Uber Member #15 Feb 23, 2007, 09:42 AM
You think your confused,I work with this stuff everyday, look at how much I need to remember. (puckers lips with index finger going up and down rapidly)

I would use the 3-#4/0 &1#2/0 URD cable.

The separate ground wire he says most people do, needs to be closely bundled with the other wires, and the insualtion must be rated for direct bury, so if he is selling them USE then fine, but you told me he sold you THHN, which most is also rated THWN, suitable for a conduit in trench, but not direct buried.

So best to use what he has for 4 wire URD trailer cable, the 3#4/0 &1#2/0, make it long enough so there are no splices, (splices will give you trouble sometime in the future). This will give you a good quality trouble free installation.
 mdmaynard Posts: 40, Reputation: 1 Junior Member #16 Feb 23, 2007, 09:52 AM
I am beginning to understand why it takes a real electritian to do these things now :-)

I appreciate your input and help. Now I just have to sell the cable I bought so I can buy the correct stuff :-)

Appreciate all your help very very very much.

Now one last question.

When I connect to the panel in the house will I use anti-oxidant on the service wire connections in the box?
 tkrussell Posts: 9,638, Reputation: 722 Uber Member #17 Feb 23, 2007, 11:29 AM
Yes any aluminum wire connection into a mechanical or compression lug must be coated with anti oxidant compound.

If you cannot sell the wire, you may get decent money by stripping it and selling to a scrap yard.Worth looking into.
 mdmaynard Posts: 40, Reputation: 1 Junior Member #18 Feb 25, 2007, 08:46 AM
I connected the stripped 2/0 wire to neutral in box, one of the 4/0 to the ground in box, the other two 4/0 went to the main lugs in box.

At the meter disconnect I am a bit confused. It is a 200 amp box the breakers connect to 2 sets of lugs with three places to connect wires on each set. Then there is the bar which has the ground running down to the earth ground rod.

Where would the neutral go?

I tried to wire 2 of the 4/0 to two of the places on one of the breakers lug sets and then I ran the 2/0 neutral to the third place in the lug set and then the ground I ran to the ground bar that has ground wire going to rod in earth. The bar has a white wire going up from the bar to past the meter.

Wiring this way did not work, what did I do wrong?
 tkrussell Posts: 9,638, Reputation: 722 Uber Member #19 Feb 25, 2007, 09:08 AM
First , the 4/0 should be a neutral, will have a white, or some color, stripe on it, the 2/0 si for the equipment ground.

The bar that has the white wire coming from the meter is where the neutrals and equipment ground all connect.

Can you furnish a picture of the meter/disconnect or give me make and model #?
 mdmaynard Posts: 40, Reputation: 1 Junior Member #20 Feb 25, 2007, 09:55 AM
Originally Posted by tkrussell
First , the 4/0 should be a neutral, will have a white, or some color, stripe on it, the 2/0 si for the equipment ground.

The bar that has the white wire coming from the meter is where the neutrals and equipment ground all connect.

Can you furnish a picture of the meter/disconnect or give me make and model #?

Attached is pic.

So should one 4/0 go to left lug and the other go to the right lug, and the ground and neutral go to the ground bar at the left of the box. Is this correct?
Attached Images

 Question Tools Search this Question Search this Question: Advanced Search

## Check out some similar questions!

Hi all, We are building a apartment above the garage,my question is what size wire do I need to run from the 200 amp panel to the 100 amp panel roughly 130' away? I want to use aluminum wire as I think copper would be to costly. Thanks for your help in advance, Dude :eek:

I am looking to find out how big the wire needs to be to carry the load. This will be a 100 amp service coming from a 200 amp main . It will need to travel 200 to 250 ft underground to a barn. If some one could help me that would be great thaxs)))

100 amp service vs. 200 amp service [ 5 Answers ]

The house I just bought was built in 1952. It's a 3 bedroom, 1 bathroom with the standard screw in fuses (total amps unknown). Presently I'm doing a remodel. Adding a third bedroom & extra bathroom, washer & dryer, dishwasher, newer & larger refrigerator, bigger microwwave, probably 3 window air...

200 amp or 100 amp [ 6 Answers ]

Which is better, a 100 amp circuit box or a 200 amp circuit box?

200 amp service with a 200 amp outdoor breaker [ 1 Answers ]

I need to know how to wire a 200 amp outdoor breaker enclosure.I have 4/0 scu cable for my service head to the meter,and 4/0 scu from meter to breaker enclosure.Then from the breaker enclosure I have 4/0 ser cable to my panel.What is the proper wiring method in the enclosure,please help.