320 Meter and 2 Separate 200 Amp Mains

traumadoc2b · Sep 18, 2014

I have had a few electricians out about rewiring my house, built in 1969 with aluminum wiring. The house had a lateral service entering a detached garage where there is currently a 200 amp main panel. There is a 150 amp breaker from the main feeding a sub panel in the attached garage - this sub supplies the house.

In addition to the branch circuits being aluminum without the correct connections to each device, some of the circuits are overloaded (12 AWG Al on 20 amp breakers), there are some open splices in the attic and garage, and the cables are not protected with bushings as they enter the panel through the knockouts.

Back to the electricians - I don't think anyone seems to be too interested because they probably don't want to fish all that cable through the walls. It's a big job, one that I'm certainly not too excited about doing myself. I do however feel that I need to start making progress to update the electrical and make things safer. One suggestion had been to upgrade to 400 amp service and have 2 separate 200 amp mains, since the house and garages are detached from one another. Then have a 100 amp sub in the basement, to allow for shorter home runs on the re-wire within the basement and to the first floor receptacles.

Since the feeder for the existing sub runs through the structure of the detached garage, then outside and underground to the attached garage and house, I'm certain that there will need to be grouped disconnects for the new main in the detached garage and feeder to the house/attached garage. Even if it wasn't required, I would want the feeder to have overcurrent protection. One of my questions is about the required size of this cable and grounding for the main in the house/attached garage. The main for the house will be separate, beginning at the 320 meter socket, there will be a disconnect and overcurrent device, and this will supply the entire load for that structure (house and attached garage), yet it's still supplied by a feeder, not a service conductor because of the disconnect just inside the detached garage from the meter, next to the other main, right? So, what size do the conductors need to be to the 200 amp main in the house? Is 4/0 Al enough?

Since the structures are separate, do I ground the service to the house at the disconnect in the detached garage (that's where service conductor ends and feeder begins), or I have to install a separate grounding electrode conductor at the house, at that main panel? My inclination would be to have the GEC set up at the OCP in the detached and use an equipment grounding connector within the feeder to the main in the house, keeping the neutral and ground separated within that main panel.

Bib Overalls · Sep 19, 2014

What are your run lengths? 4/0 is good for 200 amps in most residential situations. However, it might not be sufficient for longer runs. There are a number of of on line wire gauge calculators and they are easy to use if you know the load and the distance from the service entry/meter to the actual point of use.

wyliesdiesels · Sep 19, 2014

First off, i would get rid of the branch circuit al wiring right away. But u already know tha!

Second, if i understand u correctly u have an attached and a detached garage with the service coming in on the detached garage. A feeder feeds the house from the detached garage underground to a panel in the attached garage.

Reading through NEC 310.15(b)(7), the sizes in the corresponding table are only allowed to be used if feeding ALL the loads in the dwelling. By your description, it sounds like this is the case! So yes 4/0 AL would be allowed for 200a.

What size wire do u currently have feeding the house? Also, u talked about upgrading to 400a(320) service....what large electrical loads do u have- stove, WH, dryer, AC, electric heat, hot tub? How many sq ft is the house? U may not need to upgrade your service depending on your loads!

Charles (in GA) · Sep 19, 2014

I'm actually surprised that you haven't had a fire yet!

I owned a house built in the very late '60's with aluminum branch wiring. I had wire burning at a couple of the receptacles that the insulation was melted and burned for a foot or so from the connection. I quickly set about replacing all of the receptacles with CO/ALR receptacles that were acceptable for both copper and aluminum, and coated the wires with no-alox paste too. This bought me several years while I replaced the wiring, circuit by circuit. I was about half done when I sold the house.

If you haven't, start pulling out receptacles. I'll bet you will find one or more that have been hot or burning.

Charles

traumadoc2b · Sep 19, 2014

So the feeder run to the sub in the attached garage/house is probably 45' or so. I agree that in theory it is handling the entire load of the dwelling - the attached garage/house combo is a completely separate building from the detached garage. My only concern in interpreting the code is that the feeder runs through the structure of the detached garage. There are no terminations or junctions in the detached garage, other than the planned sole 200 amp breaker in its own dedicated panel, to allow for service disconnect and overcurrent protection, where the service conductor will end and feeder begins.

I'm not sure what size the Al wire is now, currently feeding the sub panel in the house. I know it looks newer than the house, which was built in 1969. I have looked at the outer jacket on the cable, but don't see anything printed on it suggesting the size, manufacturer, etc. I know it's big.

The house is over 3k sq ft, with a currently unfinished basement. We might want to finish the basement in the future, add heated tile flooring in the bathroom, etc. We have 2 HVAC units, one for upstairs the other down. Running a few dehumidifiers in the basement to try to keep the humidity to a reasonable level, although these keep tripping the current breaker. Existing dryer and range/oven, furnace are gas. Although I think we can get by in the house right now w/ 150 amp (we are currently getting by), I think the size of the house and potential for future renovations certainly warrant upgrading service to the house to 200 amp. Plus I won't have to worry about having an issue with running a 100 amp sub off of that, in the basement.

This is the existing main in the detached garage. The meter socket is opposite this, on the exterior wall.

Here are some photos from the existing sub in the attached garage/house.

vTXcWs_oYnArm13iQtLEV9pT5IC4WdUqtgKRgfnGEGM=w407-h543-no

I pulled down this section of drywall to see exactly what was going on underneath. I don't know what some yahoo was thinking with the conduit job here. Apparently you can connect and ground conduit to sheetrock and it's intended to house NM cable...

Here is the feeder as it enters the sub. Nice bushing protecting the cable at the knock out, right?

Notice the end of the neutral wire from the feeder is not connected to any lugs - it's just capped with electricians tape.

The neutrals and grounds are mixed together. Remember that this is a sub panel, not kosher as far as I know.

Aluminum 12 AWG on 20 amp breaker:

demaele · Sep 19, 2014

For general lighting loads of the house the NEC require a min. of 3 watts per square foot which works out to about 480 square feet for each 15 amp circuit loaded to 80 percent. Then you have to add in the rest of your loads which are the kitchen, laundry etc. to come up with a total load calculation. a master electrician in your area should be able to do that for you.

demaele · Sep 19, 2014

In answer to your question about grounding, both buildings need to be grounded separately. The house panel is no longer a sub-panel since it is a separate building. If you have water service to the detached garage you will need to have a cold water ground as well as at least one ground rod at the detached garage In the house you need a cold water ground as well as a driven ground rod. The code requires that there is 25 ohms or less resistance to ground or you need to install another ground rod at least 6 feet from the first one. In Denver the process of substantiating the less than 25 ohms is too difficult since it takes specialized equipment that most electricians just add another ground rod.

davetulk · Sep 20, 2014

I did the same thing for my house and detached shop...320 meter 200 house 150 shop.

This was on the outside of the building...code here in Florida to have disconnects on the outside for fire department.

Because the actual breaker panels as considered sub panels to the disconnect I had to un bond the panel and have separate Neutral and Ground bars.

Also had to have separate ground rods at both buildings.

Hope it helps

Gerald O · Sep 20, 2014

You know, there are better tools to cut drywall with than a hammer. A utility knife and a straight-edge comes to mind...

traumadoc2b · Sep 20, 2014

Well, you know when all you have is a hammer, everything looks like a nail! I suppose if I had unpacked and organized all my tools before I went to look behind the wall there, I might have used the utility knife.

The grounding rod for the house is going to be a pain because there is a brick walkway and then stairs for a deck between the attached and detached garage, and just outside of where the current sub panel resides. The driveway is in front. There is no easy place to put it - I can figure it out, but it's going to be a pain. I had planned on 2 new grounding rods at the service entrance behind the detached garage, at least 6' apart.

I'm also confused though, because I would think that the feeder (leaving from the disconnect/overcurrent protection device at the service entrance) will need to include an equipment grounding conductor. So I'm also supposed to connect a grounding electrode to the bus in the main panel that's being fed? And I thought the neutral and ground bus bars should be unbonded.

I'll have to check on the disconnects, but I think putting them inside the detached garage will be OK. As long as they are grouped together and marked, I know it's compliant with NEC. It will save me from purchasing one additional disconnect and from having to buy outdoor enclosures.

Thanks for the photos, davetulk.

Engineer from Duke Energy is coming Wednesday to see if it's even possible to get 400 amp service off our current lateral. Hopefully he'll be helpful and forthcoming with other advice. Assuming that goes OK, I'll probably reach out to the building department again before making any further decisions.

davetulk · Sep 20, 2014

You need a groud conductor the whole way through. Main rule need to follow is any sub panel off a main disconnect needs the neutral and ground unbonded.

All circuits in that sub panel need the neutrals and and grounds going to their respective bars and not be mixed.

In a non sub panel which is bonded the neutral and ground bars are interchangeable.

traumadoc2b · Sep 20, 2014

So I gather that as long as the neutral and ground bars are not bonded at the new main panel in the attached garage/house, it is OK and in fact I should have both a ground from the feeder (which will have it's own ground rod at the service entrance/disconnect) as well as a dedicated grounding conductor (rod and cold water bond) attached directly to the ground bus bar in that main panel.

davetulk · Sep 22, 2014

traumadoc2b said:
So I gather that as long as the neutral and ground bars are not bonded at the new main panel in the attached garage/house, it is OK and in fact I should have both a ground from the feeder (which will have it's own ground rod at the service entrance/disconnect) as well as a dedicated grounding conductor (rod and cold water bond) attached directly to the ground bus bar in that main panel.

Yup...you need the ground in the feeder....just needs to be un bonded from the neutral at the main panel. In the disconnect panel on the outside I do have them bonded together.

traumadoc2b · Sep 22, 2014

From looking at the photos above, does anyone have a good idea on the size of the wires in the feeder cable?

Charles (in GA) · Sep 22, 2014

traumadoc2b said:
So I gather that as long as the neutral and ground bars are not bonded at the new main panel in the attached garage/house,..............

The "new main panel" is actually a sub panel. The 200 amp disconnects are the "new main panel".

Charles

theoldwizard1 · Sep 22, 2014

traumadoc2b said:
The neutrals and grounds are mixed together. Remember that this is a sub panel, not kosher as far as I know.

This was acceptable practice at one time.

traumadoc2b · Sep 24, 2014

So, the engineer from the POCO was out to the house today with some good news. It looks like our existing lateral should be sufficient size for 320 service.

I am going to move forward with contacting the city regarding my proposed work and see what they say. If all goes well, will move forward with permits and scheduling work.

I did manage to get a better look at the existing feeder from the shop to the house. It is SER with (3) 4/0 aluminum conductors and a 2/0 EGC. Given that it will supply the entire load to the dwelling (house, separate structure), and according to previous posts from contributors, I think it will be of sufficient size. Will see what the inspector says when applying for the permit.

Eaglewolf · Sep 25, 2014

For 320 meters with a voltage drop of 5% allowed you would need to run 700mcm copper or 1000mcm alum. I've found this website very helpful with this type of questions.

http://www.paigewire.com/pumpWireCalc.aspx

wyliesdiesels · Sep 27, 2014

traumadoc2b said:
So the feeder run to the sub in the attached garage/house is probably 45' or so. I agree that in theory it is handling the entire load of the dwelling - the attached garage/house combo is a completely separate building from the detached garage. My only concern in interpreting the code is that the feeder runs through the structure of the detached garage. There are no terminations or junctions in the detached garage, other than the planned sole 200 amp breaker in its own dedicated panel, to allow for service disconnect and overcurrent protection, where the service conductor will end and feeder begins.....

Here is the feeder as it enters the sub. Nice bushing protecting the cable at the knock out, right?

Notice the end of the neutral wire from the feeder is not connected to any lugs - it's just capped with electricians tape.

The neutrals and grounds are mixed together. Remember that this is a sub panel, not kosher as far as I know.

Aluminum 12 AWG on 20 amp breaker:

I see no one else responded so here goes...

Answering in order of bold quotes above:

The feeder running through the detached garage shouldnt matter. Since its SER the thing u have to watch for is whether its covered in insulation or not and if it is what percentage of the whole cable is. Depending on this, the ampacity of SER needs to be lowered to 60* c ampacity...

Good thing u caught the bushing!

The neutral being capped and the bare EGC being used as a neutral is a BIG NO-NO. This is because neutral return current could flow through grounded paths. Pre-2008 code allowed 3-wire feeds but the neutral was insulated and NOT bare. Also, if a 4-wire cable was used the panel should have been setup as 4-wire. This should be fixed! Buy a ground bar and separate things.

Depending on when this panel was done, the mixed neutral and grounds would have been to code but not kosher by todays code!

Al branch circuit wire for general use circuits was a bad idea and idiots exasperated the issue by putting the wrong size breaker on 12ga al! I hope u at least change the breaker!

demaele said:
In answer to your question about grounding, both buildings need to be grounded separately. The house panel is no longer a sub-panel since it is a separate building. If you have water service to the detached garage you will need to have a cold water ground as well as at least one ground rod at the detached garage In the house you need a cold water ground as well as a driven ground rod. The code requires that there is 25 ohms or less resistance to ground or you need to install another ground rod at least 6 feet from the first one. In Denver the process of substantiating the less than 25 ohms is too difficult since it takes specialized equipment that most electricians just add another ground rod.

I think u may be confusing 2 things. EGCs and grounding electrodes are 2 different animals! People commonly do this because the 2 share a common name. EGCs are for clearing fault current and grounding electrodes(rods, plate, ufer and sometimes water lines, which must meet certain requirements; water lines are primarily bonded for safety) are for groundin lightning strikes. Yes each detached building needs a grounding electrode and new installations require a 4-wire feeder IF the building is fed from another detached building!

traumadoc2b said:
Well, you know when all you have is a hammer, everything looks like a nail! I suppose if I had unpacked and organized all my tools before I went to look behind the wall there, I might have used the utility knife.

The grounding rod for the house is going to be a pain because there is a brick walkway and then stairs for a deck between the attached and detached garage, and just outside of where the current sub panel resides. The driveway is in front. There is no easy place to put it - I can figure it out, but it's going to be a pain. I had planned on 2 new grounding rods at the service entrance behind the detached garage, at least 6' apart.

I'm also confused though, because I would think that the feeder (leaving from the disconnect/overcurrent protection device at the service entrance) will need to include an equipment grounding conductor. So I'm also supposed to connect a grounding electrode to the bus in the main panel that's being fed? And I thought the neutral and ground bus bars should be unbonded.

I'll have to check on the disconnects, but I think putting them inside the detached garage will be OK. As long as they are grouped together and marked, I know it's compliant with NEC. It will save me from purchasing one additional disconnect and from having to buy outdoor enclosures.

Thanks for the photos, davetulk.

Engineer from Duke Energy is coming Wednesday to see if it's even possible to get 400 amp service off our current lateral. Hopefully he'll be helpful and forthcoming with other advice. Assuming that goes OK, I'll probably reach out to the building department again before making any further decisions.

All main service panels need to have grouding electrodes. All panels in detached structures need them as well.

The main service panel is the only place where the neutral and ground bars are bonded. ALL new subpanels should have an insualted/isolated neutral bar with a separate grounding bar. Existing subpanels installed pre-2008 code cycle with 3-wire feeders and bonded neutral and ground bars are grandfathered in! Hopefully that answered your questions and confusion!

davetulk said:
You need a groud conductor the whole way through. Main rule need to follow is any sub panel off a main disconnect needs the neutral and ground unbonded.

All circuits in that sub panel need the neutrals and and grounds going to their respective bars and not be mixed.

In a non sub panel which is bonded the neutral and ground bars are interchangeable.

Pre-2008 code allowed subapanels to have bonded neutral bars. Yes new feeders need the EGC from panel to panel.

traumadoc2b said:
So I gather that as long as the neutral and ground bars are not bonded at the new main panel in the attached garage/house, it is OK and in fact I should have both a ground from the feeder (which will have it's own ground rod at the service entrance/disconnect) as well as a dedicated grounding conductor (rod and cold water bond) attached directly to the ground bus bar in that main panel.

I think i answered this several times above but i will add to it. The panel at the house would be considered a sub panel since theres a disconnect in the main service panel in the detached garage. Think of it like this. Neutral and grounds are mixed and bonded in the first main service panel! After a disconnect, the neutral bar needs to be isolated and unbonded with a 4-wire feeder. Remember, this applies to installs done post 2008 code cycle!

BTW a grounding conductor is an EGC/equipment grounding conductor and a grounding electrode is a rod. A GEC/grounding electrode conductor is the wire that connects rods to the panel.

davetulk said:
Yup...you need the ground in the feeder....just needs to be un bonded from the neutral at the main panel. In the disconnect panel on the outside I do have them bonded together.

Wrong. The main service panel SHOULD have grounds and neutrals bonded together!

Eaglewolf said:
For 320 meters with a voltage drop of 5% allowed you would need to run 700mcm copper or 1000mcm alum. I've found this website very helpful with this type of questions.

http://www.paigewire.com/pumpWireCalc.aspx

The distance isnt 320 meters! Its approx 45'. The title means a 320 AMP meter!

davetulk · Sep 28, 2014

If the main panel is behind an external disconnect it needs to be unbonded. If the main panel has the main disconnect in it then it does need to be bonded.

Sent from my iPad using Tapatalk

wyliesdiesels · Sep 29, 2014

davetulk said:
If the main panel is behind an external disconnect it needs to be unbonded. If the main panel has the main disconnect in it then it does need to be bonded.

Sent from my iPad using Tapatalk

Youre confusing things by saying main panel behind a disconnect. If a panel is behind a disconnect it is considered a subpanel and NOT the main service panel or in NEC terms service entrance panel...

traumadoc2b · Sep 29, 2014

I went and dropped a grand at the big box stores this w/e, gearing up for the service upgrade. Also talked to the AHJ again, and have their unofficial approval based upon my rough sketch and notes on the proposed work. I'll pull the permit next and schedule some time off at work, hopefully in the next week or two.

I'm excited about getting this done. Once I get the new panel in the garage, I can finish pulling down that god-awful peg board, re-wire it, put up drywall, and start installing shelving, workbenches, etc. http://www.garagejournal.com/forum/showthread.php?t=262012

I decided on 2/0 copper THHN for the service conductors - from the meter can to the shop main and disconnect for the house. Planning to put these in PVC. Using schedule 40 as I couldn't find SCH 80 at the store, and not in 2 1/2", which is what I think I would need for 6 conductors at 2/0 each. I'll double check with the AHJ to make sure SCH 40 is legit for the service entrance.

Hey davetulk, what size and schedule PVC did you use? I can't tell from the photos, but the piece connecting the two disconnects definitely looks smaller than the section from the meter base to the first disco.

Does anyone know if Eaton or Square D ground/neutral bars will fit in a Siemens panel? Have seen the former, but not the latter in the store, and I want to add one for the neutrals on the main for the house.

Anyone have estimates on how long this should take - replacing the meter base, replacing the main panelboard, installing the new disconnect for the house next to it, and getting ready for inspection? I should be able to have the POCO out at 8:30am to disconnect the lateral from the transformer and pull the meter. I'm hoping to have the work done and call the inspector back out by about 3-4pm, then have the POCO replace the meter and get us back on the grid.

davetulk · Sep 29, 2014

Can't remember exactly...but to the first I think is 3" and to the second it's 2" inch. I used Sch 80 just because it was exposed.

To the first disconnect is bigger because it has 6 conductors in it. To the second disconnect only 3 conductors.

The conduit to the panel in the house and the panel in the shop (not pictured) are 2".

I have attached the full size image. One other thing that was added not in the photo is the connection of the ground to the grounding rods. In the pic the ground is connected to the ufer ground in the footings of the house. Then there is another to the ground rods. Inspector made me use both.

wyliesdiesels · Oct 2, 2014

traumadoc2b said:
I went and dropped a grand at the big box stores this w/e, gearing up for the service upgrade. Also talked to the AHJ again, and have their unofficial approval based upon my rough sketch and notes on the proposed work. I'll pull the permit next and schedule some time off at work, hopefully in the next week or two.

I'm excited about getting this done. Once I get the new panel in the garage, I can finish pulling down that god-awful peg board, re-wire it, put up drywall, and start installing shelving, workbenches, etc. http://www.garagejournal.com/forum/showthread.php?t=262012

I decided on 2/0 copper THHN for the service conductors - from the meter can to the shop main and disconnect for the house. Planning to put these in PVC. Using schedule 40 as I couldn't find SCH 80 at the store, and not in 2 1/2", which is what I think I would need for 6 conductors at 2/0 each. I'll double check with the AHJ to make sure SCH 40 is legit for the service entrance.

Hey davetulk, what size and schedule PVC did you use? I can't tell from the photos, but the piece connecting the two disconnects definitely looks smaller than the section from the meter base to the first disco.

Does anyone know if Eaton or Square D ground/neutral bars will fit in a Siemens panel? Have seen the former, but not the latter in the store, and I want to add one for the neutrals on the main for the house.

Anyone have estimates on how long this should take - replacing the meter base, replacing the main panelboard, installing the new disconnect for the house next to it, and getting ready for inspection? I should be able to have the POCO out at 8:30am to disconnect the lateral from the transformer and pull the meter. I'm hoping to have the work done and call the inspector back out by about 3-4pm, then have the POCO replace the meter and get us back on the grid.

4 or more current carrying conductors in a raceway require derating. I hope u factored this in.

And sch 80 is required where subject to damage.

Cmreschke · Oct 2, 2014

From disconnect to house needs to be 250 aluminum or 3/0 copper as it no longer is a service from the disconnect but it is a sub panel.
Bond the neutral to the ground bar at both the service disconnect and at the house, it is a seperate out building. Both mains need to be grouped per nec.
Your going to have to run four wires to the house, and check the ser to see if it's rated for underground use, I'm not sure that it is even if it's in conduit.

wyliesdiesels · Oct 2, 2014

Cmreschke said:
From disconnect to house needs to be 250 aluminum or 3/0 copper as it no longer is a service from the disconnect but it is a sub panel.
Bond the neutral to the ground bar at both the service disconnect and at the house, it is a seperate out building. Both mains need to be grouped per nec.
Your going to have to run four wires to the house, and check the ser to see if it's rated for underground use, I'm not sure that it is even if it's in conduit.

If u read the applicable code section, he can use that size if it carries the full load of the house. And no that is incorrect, grounds and neutrals are not to be bonded in separate out buildings. Any and all NEW(2008 code cycle) subpanels(after the first disconnect), are to have insulated neutral bars!!

And no SER CANNOT be used underground, conduit or not!

Cmreschke · Oct 2, 2014

In seperate out buildings you do bond the neutral, I just went thru 2011 code update class for michigan, it was brought up for conversation, you still bond the neutral to ground in this situation.

Cmreschke · Oct 2, 2014

And yes as correct as it is to size his conductor for the load why not size it per the breaker that is feeding it? If you decide you want to only size it for your current load you leave no room for expansion, I would hate to hear "I should have gone bigger" those famous last words we all hear and read on this site.

traumadoc2b · Oct 3, 2014

Do I really need to de-rate 6 strands of 2/0 in a 3" length of 2" diameter SCH 80 - it's just going to protect the conductors between the meter can and the first main, which will be mounted back to back on an exterior wall. From the looks of davetulk's photos, he has 6 conductors running in about 1' of PVC. Assuming he used 2/0 copper as well.

From what I have read, the 4/0 SE cable I currently have connecting the detached garage and house should be fine to use for the 200 amp panel. The reason is that although it is technically a sub (it's fed by a disconnect), it will supply the entire load of a separate building. If anyone has anything further to add, please let me know. I will also reach out to the AHJ here to confirm.

I will need to use SCH 80 for the lateral to the meter can, luckily I think Menards has it in stock.

Here's the meter socket I am going to use.

CacsREW3DZwq1kLQmfJ1QT5t-2rK_FYw2pdbfBBz-nI=w572-h763-no

Drove the ground rods in yesterday with my son's help, 5/8" x 8', two of them about 10' apart. I put the acorn clamps on before I beat them up with the sledge hammer, just in case. I heard some people say that the top of the rod had been smashed in enough with the hammering to keep the clamps from fitting on after the rod was in the ground.

Anyone have a time estimate for me on completion (change out meter socket, replace main panel, and install disconnect to feed house)?

04fivefour · Oct 3, 2014

traumadoc2b said:
I will need to use SCH 80 for the lateral to the meter can, luckily I think Menards has it in stock.

Yes they do, at least my store does. It is kept out in the yard (the people in electric had no idea that it was different from the SCH40 on the shelf). They have up to 2 1/2 in. I just finished my trench a couple weeks ago, could have went direct bury but it was straight across my (gravel) driveway.

brewchief · Oct 4, 2014

Does that SER cable feeding the house panel go underground? If so what is your plan to fix that?

Time it takes will vary greatly depending on how much prep you can do ahead of time, how complete your material list is and how quick you can work. I've know pros that would have it done in a half day because they were prepared and other pros that would take two days because they were not prepared at all.

wyliesdiesels · Oct 4, 2014

Cmreschke said:
In seperate out buildings you do bond the neutral, I just went thru 2011 code update class for michigan, it was brought up for conversation, you still bond the neutral to ground in this situation.

No u do not! Do u realize what could happen if u bonded the neutral on a 4-wire subpanel and the neutral connection went bad, came loose or developed a high impedance connection? The EGC, and any parallel metal pathways between the buildings WOULD become energized with neutral return current. Pre 2008 code didnt take this into account and is just the reason why this particular code was changed then! Old installations are of course grandfathered in!

Whoever said that is wrong! But since u dont believe me, u can read it from someone else:

http://www.mikeholt.com/technical.p...onnections, The Right and Wrong Way (06-25-01)

Cmreschke said:
And yes as correct as it is to size his conductor for the load why not size it per the breaker that is feeding it? If you decide you want to only size it for your current load you leave no room for expansion, I would hate to hear "I should have gone bigger" those famous last words we all hear and read on this site.

If u read the particular code section then he can use the conductors he plans on using because the full load of the dwelling will be on the feeder! So im confused what youre trying to say here.

traumadoc2b said:
Do I really need to de-rate 6 strands of 2/0 in a 3" length of 2" diameter SCH 80 - it's just going to protect the conductors between the meter can and the first main, which will be mounted back to back on an exterior wall. From the looks of davetulk's photos, he has 6 conductors running in about 1' of PVC. Assuming he used 2/0 copper as well.

From what I have read, the 4/0 SE cable I currently have connecting the detached garage and house should be fine to use for the 200 amp panel. The reason is that although it is technically a sub (it's fed by a disconnect), it will supply the entire load of a separate building. If anyone has anything further to add, please let me know. I will also reach out to the AHJ here to confirm.

I will need to use SCH 80 for the lateral to the meter can, luckily I think Menards has it in stock.

Here's the meter socket I am going to use.

Drove the ground rods in yesterday with my son's help, 5/8" x 8', two of them about 10' apart. I put the acorn clamps on before I beat them up with the sledge hammer, just in case. I heard some people say that the top of the rod had been smashed in enough with the hammering to keep the clamps from fitting on after the rod was in the ground.

Anyone have a time estimate for me on completion (change out meter socket, replace main panel, and install disconnect to feed house)?

No u dont have to derate those. Sorry when i said that comment i didnt realize you were referring to a 3" ******. Code requires derating when conductors are bundled over 24".

And the ampacity allowance with smaller wire is only allowed when the feeder supplies the entire load of the dwelling NOT just a separate building(such as a shop)...

brewchief said:
Does that SER cable feeding the house panel go underground? If so what is your plan to fix that?

Time it takes will vary greatly depending on how much prep you can do ahead of time, how complete your material list is and how quick you can work. I've know pros that would have it done in a half day because they were prepared and other pros that would take two days because they were not prepared at all.

What pic is that in? I missed it...

brewchief · Oct 4, 2014

wyliesdiesels said:
What pic is that in? I missed it...

We have pics of the main panel that's in a detached garage with the meter on the other side of the wall and pics of the house panel(subpanel), there is a SER leaving the garage feeding the house, I haven't seen any pics of what's in between but it has to get from one to the other. It could transition to a different type of wire and run underground or maybe it stays SER and is routed above ground in some fashion but looking at that subpanel I kinda doubt it.

traumadoc2b · Oct 4, 2014

brewchief said:
We have pics of the main panel that's in a detached garage with the meter on the other side of the wall and pics of the house panel(subpanel), there is a SER leaving the garage feeding the house, I haven't seen any pics of what's in between but it has to get from one to the other. It could transition to a different type of wire and run underground or maybe it stays SER and is routed above ground in some fashion but looking at that subpanel I kinda doubt it.

Well, that may be a problem. Most of the run is in the attic or wall, however there is about a 3' gap between the detached garage and the house. There's a brick walkway that transitions to wooden stairs up to a deck. I'm not exactly sure if the SER runs above ground, behind the stairs, or if it runs under the brick. From what I can see, there is a short EMT elbow that pops out of the baseplate for the exterior wall, which might be as short as from there to the other side of the brick exterior wall (and remain above ground). It looks sort of straight from the angle of the picture, but it does bend like an elbow.

I know that whatever I do, it's going to be much better than what I currently have. Just pulled down some more pegboard and drywall today, prepping for the install, and found the SER going through a notch in the top plate, with no protection, and it's "secured" into place with a bent nail. Another example of things I plan to fix with this service upgrade.

Even if it is underground, it's about a 3' run. Is that really that bad? Part of the problem is that if I was going to run THWN through the conduit (underground), I would need to add a junction box somewhere to transition from SER to THWN as the cable leave the detached garage. Besides the J-box and the added frustration, I'm not sure how to make those splices. And I don't really want to run conduit all the way across and the detached garage.

wyliesdiesels · Oct 4, 2014

The issue with SER undergroud is that the conductors arent rated for wet loctions and can develop issues when exposed to water, especially when using AL conductors...And conduit does fill up with water no matter how good it was done! The conductors can turn into a paste like substance if water gets into the conductor through a nick in the insulation...

Yes u would need j boxes and split bolts or kearney bolts which arent cheap...

traumadoc2b · Oct 4, 2014

Argh! So I sort of reluctantly pulled up one of the half rotted steps to the deck. There's dirt under there, and I carefully hand dug a little, but I didn't seem to find the conduit or SER. From looking more closely to where the SER goes within the detached garage, I'm pretty sure now that it runs on a little bit of a diagonal, within conduit, under the brick, to just under that first step (probably deeper than I was digging) and up through the edge of the foundation and the baseplate.

Maybe another option would be for me to pull the SER back out of the conduit and into the detached garage and then run it under the deck stairs, but keep it above ground. Thoughts?

theoldwizard1 · Oct 5, 2014

wyliesdiesels said:
And sch 80 is required where subject to damage.

For all practical purposes, "subject to damage" is any thing below 48", especially if it goes into the ground.

traumadoc2b · Oct 5, 2014

wyliesdiesels said:
The issue with SER undergroud is that the conductors arent rated for wet loctions and can develop issues when exposed to water, especially when using AL conductors...And conduit does fill up with water no matter how good it was done! The conductors can turn into a paste like substance if water gets into the conductor through a nick in the insulation...

Yes u would need j boxes and split bolts or kearney bolts which arent cheap...

What about some fargo connectors, or a parallel groove single bolt connector?

Or a splicer terminal block, like this one that's $58. I like that it's less of an issue to insulate the fargo or split bolt connections from one another. I would still need another device to bond the EGC together.

I like the wireway trough idea and I can see what you're talking about. However, I can't find where I would be able to buy one... Looks like I would need at least a 4x4 or 4x6 in trough. Of course, also having trouble finding that big of a j-box. I think it would need to be at least 15" across (6 x 2 1/2" SCH 80 PVC for j-box with splice).

Since the SER feeder I have now is existing and this isn't a remodel, just a service upgrade, if I were to use it without modifying it, what are the chances the AHJ is going to give me flack about it? I could plan to fix it when I replace the deck and have everything between the shop and house pulled up, so that I can really do it right and clean.

traumadoc2b · Oct 7, 2014

First phase of work is tomorrow. Just started to doubt if I can use THHN to connect meter can to main, back to back. I wouldn't think that being in the enclosure would be considered a wet location. Any reassurance?

brewchief · Oct 7, 2014

Most thhn is also rated thwn, if so your good

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