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Old 04-17-2012, 11:44 AM   #1
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Questions about 100-200A service upgrade


I'm having quite the time finding an electrician who will quote this. Just about all of them say that what I need is to upgrade my main panel but I want to install a new main panel that is a part of the meter base outside and make my current 100A panel a sub. Maybe you people can tell me why nobody seems to want to do this. Here are a few shots of the existing meter (note what is apparently a 60A base here)


and a shot of the conduit headed underground. Like most homes built during this era, the conduit makes a right turn underground to enter through the cinderblock, ending up coming into the back of the main panel. This conduit encloses a 4 wire feed. edit: no, actually it is only a 3 wire feed which is a problem if I want to convert the original main panel a sub.


Here's the existing panel. It's a 60's era Square-D split panel with a 30 amp sub panel for the finished basement. Those are low voltage wires to circuit taps for my home energy monitoring system btw.


The reason I don't want to upgrade this panel are as follows:
  • We won't be expanding the electrical west of this panel any more. All planned expansion (240v car charger in Garage, planned 3 season room with grid tie Solar on the roof) will be to the east.
  • Upgrading the panel will require major surgery to the walls. Due to the way the original basement is engineered there, the walls have an intricate stud pattern behind the existing panel. I'd pretty much have to rip out a 4' section and redo it to make the access large enough to handle a 200A panel.
  • Adding additional circuits to an upgraded panel will require an act of God due to the finished basement construction. There are no raceways for additional circuits.


Based on this, my thoughts were to create a new 200A main panel outside based on something like the GE model TSM420CSCUP loadcenter. Here's a shot of this panel:


This particular panel has room for three 2-pole breakers in addition to the 200A mains. I'd add a 100A 2-pole breaker for the existing panel, with the other two reserved for the garage/solar expansions.

The issue with the contractors who have quoted the job appears to be the conduit going to the existing panel. I'm not sure what's wrong with it but it is apparently not compliant with current code. Obviously the bonding needs to change, new grounding electrodes need to be driven, and a water pipe ground needs to be established to the new main panel, but what else is required?

I'd like to throughly research all the code considerations here so I can approach a contractor from a more knowledgable perspective then determine the best way to perform this upgrade. Due to POCO coordination and the need to cut household power for the duration of the job, I have no desire to DIY this one...

So what exactly is wrong with the conduit running from the existing meter base to the existing load center? Why is everybody telling me that I can't do essentially what I've described above? What are the relevant code sections that will apply to this job? Should I be chatting with my AHJ about local considerations now or should I wait until I have the code requirements down pat (assuming the latter here)?


Last edited by kwilcox; 04-17-2012 at 07:27 PM.
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Old 04-17-2012, 12:38 PM   #2
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Questions about 100-200A service upgrade


The issue I see is by adding that meter main panel outside makes that the first point of disconnect. That makes your existing panel a sub-panel and would require a 4 wire connection instead of the existing 3 wire. You will need to replace the conduit and wire feeding the converted sub-pane from the new meter main. All the grounds and neutrals in the exiting panel (now a sub) need to be separated onto separate bars; the panel; may not enough terminations to allow that.

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Old 04-17-2012, 01:33 PM   #3
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Questions about 100-200A service upgrade


Edit: I just checked the panel and you are right! That is a 3 conductor conduit: 2 blacks and 1 stranded unclad copper. Here's a shot from 2006 (all tandems have since been removed)"


I believe I'm good on terminations since this panel has separate ground/neutral bus bars that have been bonded together as shown in the photo.

I forgot to add that I'm in SE Wisconsin near Milwaukee. My local municipality is on NEC 2008 but is moving to 2011.

Last edited by kwilcox; 04-17-2012 at 01:41 PM.
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Old 04-17-2012, 01:41 PM   #4
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Questions about 100-200A service upgrade


What size are the wires? As they exist they are a service connection. Under your proposal they become branch circuit feeders.
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Old 04-17-2012, 01:43 PM   #5
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Questions about 100-200A service upgrade


I'd guess it's a matter of wire length and difficulty in cutting that conduit without damaging the wires inside, and if you stay with that conduit, based on what I can tell about it's size, the subpanel will be limited to a 60A feeder.
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Old 04-17-2012, 01:58 PM   #6
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Questions about 100-200A service upgrade


The printing on the insulation of each conductor says "2 1W 600V" which doesn't make sense to me. Here's a link to the panel shot. If you go there you can pull down a full size image that has a large amount of detail:

Link to panel shot

So it appears that my big problem with the existing conduit would be that it contains only 3 conductors (missing neutral).

Last edited by kwilcox; 04-17-2012 at 02:04 PM.
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Old 04-17-2012, 02:29 PM   #7
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Questions about 100-200A service upgrade


Where is the new meter main in relation to the old panel. If they are basically back to back it should be pretty easy to run conduit for new conductors or use SER cable. You definately need a 4 wire feed to the old panel.
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Old 04-17-2012, 04:31 PM   #8
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Questions about 100-200A service upgrade


I was planning on back to back locations. Would it be possible to just pull the existing 3 conductors out and replace with 4 new conductors? That conduit is no more than 4' long, is probably only 30% filled and should be fairly new. I believe that it was replaced when the basement wall was dug out and resealed before we bought the house. If you look closely at the picture you can see that water came in through that location at one time. That would imply that the conduit may have rusted through below ground level. I can't imagine they wouldn't have fixed that when the walls were dug out.

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Old 04-17-2012, 05:14 PM   #9
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Questions about 100-200A service upgrade


What size is that conduit and material ? To supply the basement sub-panel with 100 amps using THWN in conduit you need #3 copper or #1 Aluminum conductors. If it is rigid metal conduit (RMC) you need minumum 1" for copper and 1.25" for aluminum conductors. Since the conduit is in the ground I would replace it with Schedule 80 PVC, 1.25". I realize that means a little shovel work.

BTW the ground connection will have to be brought to the new meter main panel.
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Old 04-17-2012, 05:41 PM   #10
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Questions about 100-200A service upgrade


Great info so far. What would bother me if I was bidding this project is the fact the feeder conduit exiting the new meterbox to feed the newly branded"subpanel" will enter BELOW grade through the foundation wall.
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Old 04-17-2012, 06:14 PM   #11
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Questions about 100-200A service upgrade


And how do you plan on turning off POCO power to replace the meter?

You will not be able to call the POCO to do it, because it is illegal for a homeowner to work on electric in SE Wisconsin. This is coming from a Milwaukee area electrician for the past 14 years.

It is not possible for you to do this because of where you live. Now, really don't know why no one will touch it, if you would like, PM me and I can give you the name of a company that will, at minimum, give you a price. I don't work for them, but I used to for 10 years, and they do top quality work.

edit:sorry I missed the paragraph about you not wanting to perform the work yourself.
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Old 04-17-2012, 06:29 PM   #12
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Questions about 100-200A service upgrade


Since you are from my neck of the woods I'll give you some of the concerns I see from your pictures.

1) The lower pipe goes below grade, that would need to be rigid pipe to go below grade, but most likely, the EC would choose to raise the entry point to above grade and install a LB to make the turn to go in. This creates a problem on the inside. The existing lower pipe enters the back of the panel. If the entry point were to move up, above grade, then the wall would have to be opened to allow for access to install the conduit.

2) After scrolling thru some of your pics, it looks like you may have a drywalled ceiling in the basement? If so, this would create some issues. A new water ground would have to be run to your water meter. You would either have to fish it the entire way which is possible, but unlikely without cutting holes in the ceiling or exposed pvc to run the water ground in.

3) On a good note, that service is WAY too new to be a 60A service. I would bet money on it being a 100 A service. But I see that it is a main lug panel, where is the main? If there is no main, the service is breaking code the way it sits. If there is a main, the big issue would be refeeding that panel/s and I would have no way to advise you without seeing where the existing panel is in comparison to the new meter location.

To conclude, I see two hurdles.

1) drywalled ceiling in the basement
2) where the new meter socket is in relation to the existing panel, and how you would get between the two.
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Old 04-17-2012, 06:45 PM   #13
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Questions about 100-200A service upgrade


I think you're onto it k_buz. The electricians who came out to quote were all concerned about the below grade entrance and only wanted to do it above grade. From the way one of them talked, it sounded like a code requirement and I'm betting its because that isn't (the right kind of) rigid conduit? What section of the NEC can I look at that covers this? It would be very difficult to go in above grade however for the reasons you cite.

You are also correct about the drywall ceiling but it isn't an issue, that area has a removable soffit that conceals water pipes that go to the Kitchen. Here's a shot of them being installed back in 2005:


It wouldn't be difficult to get a grounding wire there then follow through the soffit to the unfinished portion of the basement and over to the water meter.

edit: also forgot to add that the panel is truly 100A but doesn't have a main breaker. It's one of those "6 hand movement" panels made back in the 60's. The "main" 6 breakers are labeled as such. Apparently it's still code compliant.

Last edited by kwilcox; 04-17-2012 at 07:28 PM.
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Old 04-17-2012, 07:23 PM   #14
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Questions about 100-200A service upgrade


I can't find the exact pedestals I have used over the years, but its alot like this, without the GFCIs.

http://www.milbankmfg.com/Products/C...DF/5706TTF.pdf
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Old 04-17-2012, 08:46 PM   #15
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Questions about 100-200A service upgrade


Ok, lets see what I have so far for this job:
  • dig up around old conduit to expose. I can do this.
  • remove old conduit/conductors and install new rigid conduit spec'ed for below grade burial. Run 4 conductors inside: 2@#3 copper for mains, 1@??? copper for neutral, 1@??? copper for ground
  • break bonding at the current main panel to make it a sub panel. Wire neutral to neutral buss, ground to ground buss.
  • Install 200A panel outside with new meter base. Panel manufacturer/model number TBD. I would like to stick with Square D but can't find anything that fits my requirements. I'm also under the impression that this meter base/panel needs to be approved by the local POCO
  • install 2 new grounding rods for new main panel

Now, concerning the water ground to the new main panel. Does this conductor need to be in conduit? If so, it seems incorrect to use the same conduit just installed since the conductor would have to enter the newly anointed sub-panel only to exit then go back up to the soffit then route to the water meter.


Last edited by kwilcox; 04-17-2012 at 08:51 PM.
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