# 400 Amp Upgrade / Transfer Switch



## Speedy Petey (Feb 1, 2004)

Since most 400/320A residential services are simply two 200A panels I would choose the circuit you want to transfer and keep them in one panel and install a 200A transfer switch for just that one panel. 

Keep in mind, I don't know what code your area is under, but there is a (stupid) new 2008 NEC change that states an automatically transferred load, the generator must be able to handle the WHOLE load. 
So if you do just one panel automatically, and the demand load on that panel is 150A @ 240v then the generator you get must be at least 35kW. That's 35,000 watts.
Consider that when thinking about going with a full 400A transfer switch.


----------



## AndrewF (Dec 29, 2008)

Thanks for the response.

Perhaps I'll skip the whole house transfer switch, and when it comes time to do that part of it, I'll use an indoor transfer switch and move the services I want to protect to that transfer switch with its own internal breakers.


----------



## wirenut1110 (Apr 26, 2008)

Not sure what brand generator your thinking of going with but, 
Generac has a "genready" load center that is a 200 amp panel that has the transfer mechanism installed. 

It is a Seimens load center, comes in basic and advanced. The basic just doesn't have the transfer mechanism installed yet is a little less expensive.

Just an idea.


----------



## wirenut1110 (Apr 26, 2008)

An option also with the 08 requirement with the auto switch is, you may have 20KW heat but I'd be sure they're staged. You could install an interlock so, when the generator is running, it will lock out 5-10 kw of strips. You wouldn't have full heat capabilities but, you'd have some heat and you don't always lose power in the winter.

I do this a lot with customers because, as Petey stated, your looking at a huge generator which most can't afford or justify the expense.


----------



## AndrewF (Dec 29, 2008)

I've decided to not go with the whole house transfer switch for now. Since I need to get this project completed so I can run electric to my barn.

I have located a local electrician that was laid off and is willing to help for a fee. Before I have him come out, I plan on doing as much of the preliminary work as I can.

I have attached a sketch of my plan.

My question has to do with the 400 amp dual lug meter socket.

I bought it from a guy that was going to use it, but never did. Yet he popped out the bottom two holes and one on the back of the meter socket.

I only need one bottom one (ground feed from utility) and the one in the back of the box to get inside of the house. What can I do about the 2nd bottom hole?

Can I use SE cable between the meter socket to each 200 amp panel that sit next to each other? If so, do I have to run them thru separate holes into the house or can they both go through the rear hole of the meter socket box?

Will code permit me to then drill a hole through the 2x4 separating the entrance hole from the meter socket to the second 200 amp panel or do I need to bring the SE cable into the joist void that each panel is in?


----------



## Speedy Petey (Feb 1, 2004)

AndrewF said:


> I have located a local electrician that was laid off and is willing to help for a fee. Before I have him come out, I plan on doing as much of the preliminary work as I can.


All I can say is be careful.





AndrewF said:


> I only need one bottom one (ground feed from utility) and the one in the back of the box to get inside of the house. What can I do about the 2nd bottom hole?


A weatherproof knockout seal.





AndrewF said:


> Can I use SE cable between the meter socket to each 200 amp panel that sit next to each other?


Yes.




AndrewF said:


> If so, do I have to run them thru separate holes into the house or can they both go through the rear hole of the meter socket box?


Separate holes and connectors.




AndrewF said:


> Will code permit me to then drill a hole through the 2x4 separating the entrance hole from the meter socket to the second 200 amp panel or do I need to bring the SE cable into the joist void that each panel is in?


Any hole you drill for 200A SE cable will be too big for a 2x4.


----------



## Yoyizit (Jul 11, 2008)

AndrewF said:


> Upgrading to 400 amp isn't an overkill right?


Primary Heat Source is a 5 ton HP. 
~6kW, 25A
Secondary Heat source is 20KW resistence heat. 
83A
55 Gallon Electric Water Heater 
18A or 36A
Electric Range 
50A?
Electric Microwave/Oven 
50A?
Other
http://www.wholesalesolar.com/pdf.folder/Download folder/Power-table.pdf

200A + 100A gives you less than 56A of headroom, 400A gives you 100A on top of that.


----------



## AndrewF (Dec 29, 2008)

Speedy Petey said:


> A
> 
> Separate holes and connectors.
> 
> Any hole you drill for 200A SE cable will be too big for a 2x4.


Ok, so I'll need to drill two 3.5" holes through the brick to get to each panel from outside. Not a biggie, I just wanted to see if I could do a really clean install by running both through a single hole in the back of the meter socket.

This setup is on the back of the house right near where our patio is, so anything I can do to keep a clean simple install was my goal.

I guess I could try to stagger the panel over a 2x4 and then run a hole from the meter socket on each side of the 2x4 to access each panel.

Also, when the SE cable comes into the wall cavity, I was going to leave it exposed in the wall cavity and then come into the bottom of the 200 amp panels utilizing a "compression" fitting. There is no need to run pvc conduit through the wall and then try to make the right 90 degree turn into the bottom of the panel, right?

----------

As for the laid off electrician, he was registered in this county up until a few years ago. (He lives in a different county).

Since I am only paying for his time, I want to ensure I am getting all the right components and doing the job "right" or the best way versus some cobbled up way that might still pass county inspection.


----------



## Speedy Petey (Feb 1, 2004)

AndrewF said:


> Ok, so I'll need to drill two 3.5" holes through the brick to get to each panel from outside. Not a biggie, I just wanted to see if I could do a really clean install by running both through a single hole in the back of the meter socket.


You shouldn't need a hole that big. Just big enough for the cable. You can chip away the wall behind the box to account for the connector.





AndrewF said:


> Also, when the SE cable comes into the wall cavity, I was going to leave it exposed in the wall cavity and then come into the bottom of the 200 amp panels utilizing a "compression" fitting. There is no need to run pvc conduit through the wall and then try to make the right 90 degree turn into the bottom of the panel, right?


As long as the cable is not directly subject to damage you are fine w/o PVC.


----------



## AndrewF (Dec 29, 2008)

Speedy Petey said:


> Separate holes and connectors.
> 
> 
> Any hole you drill for 200A SE cable will be too big for a 2x4.


Speedy,

I checked and the existing 200 amp SE cable is ran thru a hole in the 2x4 from the adjacent space.

Do the 2008 NEC regulations state this is forbidden or is it just bad practice?

The meter socket I bought, has a 3" hole drilled in the back of it, right where I would need to stradle the location of the 2x4....so if I can move the MS one direction, I can then use the 3" hole and drill only one through the brick wall.


----------



## chris75 (Aug 25, 2007)

Keep in mind, I don't know what code your area is under, but there is a (stupid) new 2008 NEC change that states an automatically transferred load, the generator must be able to handle the WHOLE load.


This isn't a new code, its always been the case, electricians have just ignored it, so they reworded it to really enforce it.


----------



## AndrewF (Dec 29, 2008)

Thanks...note. I have scrapped the whole transfer switch plan.

Just am upgrading to 400 amp service.


----------



## kbsparky (Sep 11, 2008)

Here is an idea: Stop thinking you have to use type "SE" cable. That stuff is bad news, as far as the _Code_ is concerned. The new _Code _has derated type SE cable now to the point that it will be impractical to use it in most installations.

Instead, install some PVC nipples directly from the back of the meter box into the backs of the panels, and then use some THWN copper lines to connect your panels. Or at least some XHHW Aluminum wires, if you can't stomach the cost of the copper. But there is so little copper required, the additional cost won't be much of a factor.

Here is your drawing, with the suggested revisions:


----------



## kbsparky (Sep 11, 2008)

Now, as to that transfer switch. It will be far easier and cheaper to simply install a generator interlock kit in one of the new panels. Will you be using Square D panels there? Those interlock kits can be installed at any time down the road, and don't have to be done right now.:no:

To deal with that 3" hole in the back, just buy a blank octagon or 1900 blank cover, and fasten it over the hole, using small truss type TEK screws or pop-rivets. Same thing for that hole in the bottom of the meter box. You don't need a "weatherproof" blank-off on the bottom of the enclosure, since those knockouts were not weatherproof in the first place. :whistling2:


----------



## Speedy Petey (Feb 1, 2004)

KB, excellent graphic. Exactly what I was talking about. 
Only problem is, the 2" nipples (in red) are going to need to be probably under 2" long. This is a real problem with back to back equipment, with a flush panel and 2x4vwalls.







kbsparky said:


> Here is an idea: Stop thinking you have to use type "SE" cable. That stuff is bad news, as far as the _Code_ is concerned. The new _Code _has derated type SE cable now to the point that it will be impractical to use it in most installations.


Can you explain this a little batter? What has changed other than having to use the 60 deg C column for branch circuits and feeders? I don't see that 310.15(B)(6) changed.


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> Instead, install some PVC nipples directly from the back of the meter box into the backs of the panels, and then use some THWN copper lines to connect your panels. Or at least some XHHW Aluminum wires, if you can't stomach the cost of the copper. But there is so little copper required, the additional cost won't be much of a factor.
> 
> Here is your drawing, with the suggested revisions:


I thought about doing that. However, the guy I bought this 400 amp meter socket from also included about 20' of 200 amp SE cable, so my plan was to just use this new cable, keeping the costs down.

When I originally was just doing a new MS and panel swap, I bought 6' of XHHW AL to use. 

My concern with the nipples is that I am going through the brick, 1/2" insulation board to the panel...and being able to get the two nipples and a piece of PVC short enough to screw into the back of the MS and panel.



kbsparky said:


> N
> To deal with that 3" hole in the back, just buy a blank octagon or 1900 blank cover, and fasten it over the hole, using small truss type TEK screws or pop-rivets. Same thing for that hole in the bottom of the meter box. You don't need a "weatherproof" blank-off on the bottom of the enclosure, since those knockouts were not weatherproof in the first place. :whistling2:


I wasnt sure if a cobbled up blanking panel like that would be permitted or not.  

As for the bottom hole, I bough some reducers (3.5" to 2") and the installed a weather tight 2" plate on. I had thought about one of the pop in blanking plates, but I didnt like how it could be pried out with a screw driver. So I spent the exra $3 to do it the way I did.


----------



## kbsparky (Sep 11, 2008)

Speedy Petey said:


> ....problem is, the 2" nipples (in red) are going to need to be probably under 2" long. This is a real problem with back to back equipment, with a flush panel and 2x4vwalls....


Never a problem with me. I simply use a Terminal Adapter, along with a BOX adapter. Fits quite nicely into that space -- about 1¼-1½" total length

Although, it looks like the OP has stated there is a brick wall to penetrate?

That should solve any problem with dealing with short sections of PVC.


Andrew, if you are still watching this thread, you can strip that SEU cable, and use the XHHW conductors in those PVC nipples. Just be sure to mark your neutral with some white tape.

No exposed service cable that way. :yes:


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> Never a problem with me. I simply use a Terminal Adapter, along with a BOX adapter. Fits quite nicely into that space -- about 1¼-1½" total length
> 
> Although, it looks like the OP has stated there is a brick wall to penetrate?
> 
> ...


Why even bother stripping the SEU cable? I wasnt planning on it going through the nipples.

I still want to drill only one hole in the wall, not two.


----------



## AndrewF (Dec 29, 2008)

After a long day of work, the new meter socket is in and the two new 200 amp panels are done.

The electrician helping me with the project said that code requires to have AFCI on bedroom circuits, so I had to drop another $130 for ACFIs...GRRR!

Looking at these photos, anything look "wrong"?

The temporary conduit is until POCO comes out and fishes 2/0 through the 3" PVC that will run to the transformer. The POCO engineer said to just run a jumper from the new MS to the old MS until they do that.

I imagine the county inspector will have a cow when he sees it....


----------



## AndrewF (Dec 29, 2008)

Original panel.


----------



## kbsparky (Sep 11, 2008)

1) I can't tell what kind of connector was utilized where the SEU cable enters those panels. The inspector might flag you on this point.

2) The other thing I might have suggested is to orient the new panels with the mains at the bottom. In many areas, an inspector probably wouldn't mind either way, but I have seen "anal" types that would throw a hissy fit with that main cable looped to the top.

I should have gotten your contact info, since I was just in the Dayton area this past week. :whistling2:

Unless you have installed new circuits for those bedrooms, you should not be required to use AFCI breakers


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> 1) I can't tell what kind of connector was utilized where the SEU cable enters those panels. The inspector might flag you on this point.


There is a 1 1/2" pvc pipe that comes from the back of the meter socket into the back of the electrical panel. It is threaded on both ends. Total length is about 4". (Whatever it took to get through brick and the 3/4" insulation board.




kbsparky said:


> 2) The other thing I might have suggested is to orient the new panels with the mains at the bottom. In many areas, an inspector probably wouldn't mind either way, but I have seen "anal" types that would throw a hissy fit with that main cable looped to the top.


I had thought about that, but the electrician helping me said it didnt matter, so we left them at the top and ran the cables up. While the inspector might give a fit, i am pretty sure it doesnt break any codes though.




kbsparky said:


> Unless you have installed new circuits for those bedrooms, you should not be required to use AFCI breakers


I have installed zero new circuits. I thought I had to put the AFCI breakers in because of it being a new panel. That being said, I dont think the inspector would have required it...I did call him and asked him if I had to do it for all living areas or just the bedrooms and that I had done only the bedrooms. He said that was fine.

We'll know for sure Monday when he comes for the final.

Make it through Dayton often?


----------



## junkcollector (Nov 25, 2007)

It looks pretty good:thumbsup:

One thing I would do before inspection is reidentify that white wire on the two pole breaker at the top of the right panel.

I do your have bonding screws in? (I hope!)

One question I have is how your temp jumper is connected to your new meter socket; if you connect the temp power to the line lugs in the meter socket and throw the bypass the lever prevents you from putting the cover on, unless your meter blanking plate has jumper bars on it.


----------



## AndrewF (Dec 29, 2008)

Today I dug the 95' trench for the new service. I dug most of it 30" deep, except for where I had to go under the line to the septic tank. I buried it 36" there in case the septic line ever had to be replaced or messed with.

Here are a few photos.


----------



## kbsparky (Sep 11, 2008)

Wow, they make you dig your own trench for underground feeds?

I get into the Dayton area several times a year. My folks live in West Carrollton. I just spent the past week there, helping them fix a few things around the house.

It's a 600 mile drive home from there, drove 11 hours yesterday.


----------



## AndrewF (Dec 29, 2008)

When I first spoke to the utility engineer, he said it would cost me 1-2k for the upgrade, including re-locating the transformer away from the house.

Through the course of our discussions, it was suggested that if I dig the trench and run 95' of conduit to the new location, they would absorb all the other costs, including the 2/0 service cable and a new transformer.

I spent about $90 on the 3" conduit and fittings, which was cheaper than the alternative. I had to run the 3" PVC underneath the septic tank line, I can only imagine if they sent one of their guys out to dig the trench, what would have happened and the extra costs to repair the damage.

I passed the inspection this morning and am now just waiting on the utility company to complete their part of the project.


----------



## AndrewF (Dec 29, 2008)

The contractor for the electric company came out and ran the new cable in my conduit for the 400 amp service.

However, they ran 4/0 which is typically rated for 200 amp service, right?

I'll call them tomorrow and see if it was a mistake, the engineer told me they'd run 2/0 for the 400 amp service.


----------



## kbsparky (Sep 11, 2008)

Nope. Nadda.

4/0 URD cable is typically rated for 315 Amps.

No call is necessary to the utility or their contractor.

2/0 is rated for 245 Amps.

Don't believe it? Click here for the ampacity chart from Southwire.

Scroll down to page 2 for the applicable chart.

Remember utilities are not subject to the NEC, which typically limits a 4/0 cable to a 200 Amp residential service.


----------



## Speedy Petey (Feb 1, 2004)

I don't know what they are referencing with that chart, but 4/0AL is good for a 200A single phase dwelling service according to NEC 310.15(B)(6).

I have seen utilities run some extremely undersized laterals. I have no idea what they base this ampacity on.


----------



## kbsparky (Sep 11, 2008)

Speedy Petey said:


> .... I have no idea what they base this ampacity on.


That's the manufacturer's own chart. Based on their own testing data. Which the utilities are free to utilize for their service laterals. And many of them do.:whistling2:


----------



## AndrewF (Dec 29, 2008)

Hmmh, I'll still call them as the engineer is the one that told me they'd run 2/0.

The county required me to run 4/0 from each panel to the MS.


----------



## AndrewF (Dec 29, 2008)

Spoke to the engineer, 4/0 is their standard for this type of service.

It'll be a few weeks before they actually move the transformer and do the hookup.

So that means i'll be running on my temporary service until then. Temporary in that on the new meter socket, I have #2 solid copper being the jumper between the contacts as the meter is still in the old MS.

Any ideas what #2 solid is rated for amp wise?


----------



## kbsparky (Sep 11, 2008)

AndrewF said:


> ...Any ideas what #2 solid is rated for amp wise?


More than you will need. 125 Amps minimum continuous. If that ain't big enough, you won't be able to afford the electric bill in any case. :huh:


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> More than you will need. 125 Amps minimum continuous. If that ain't big enough, you won't be able to afford the electric bill in any case. :huh:


Well, if the A/C is on, my wife is cooking dinner and doing laundry and the regular lights are on, it is possible to get to 100 amps  So I just was curious what the limit would be before it would either melt or cause damage to the new meter socket.

This past winter, I was drawing over 110 amps continuous  (And no, those electric bills werent fun).


----------



## AndrewF (Dec 29, 2008)

Final Update. POCO came today and installed the new vault, pad and transformer and hauled the old one away. They installed a 7200/240 25 KW transformer dedicated to just me.

I am happy to have the project completed. Now I can back fill and get the landscaping back to normal.

Here are a few photos.


----------



## AndrewF (Dec 29, 2008)

Here are a few more.

They installed a new meter, and it started at 00000 which is kind of cool to me.


----------



## kbsparky (Sep 11, 2008)

AndrewF said:


> Final Update. POCO came today and installed ...a 7200/240 25 KW transformer dedicated to just me.....


All that fuss over wire size, if you run the numbers, that is only good for 104 Amps! :laughing:


----------



## spark plug (May 5, 2009)

*acongrats on new panels*



AndrewF said:


> [Original panel.]


I'm glad you're replacing? the "old" panel. For Two reasons; 1) The Neutrals look like Spaghetti; 2)the breakers (if I'm not mistaken) look like they're Bull Dog, "Push-in" type, which were found to have the same problems as the FPE breakers. Sorry if I sound like a crusader (against FPE). I've witnessed the [near] disaster caused by them!:furious::no::drinkon't Drink and Drive!!!


----------



## spark plug (May 5, 2009)

*Customer feels "Special"*



kbsparky said:


> All that fuss over wire size, if you run the numbers, that is only good for 104 Amps! :laughing:


]
Interestingly, the Transformer is ONLY 25KVA. @ 240v. You can't "cheat" on that! But in NYC, the POCO, Con Ed always OVERRATES the Service Cables. The insulation is high quality and they run heavier loads on them than otherwise "permitted?"! :yes::no::drinkon't Drink and Drive!!!


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> All that fuss over wire size, if you run the numbers, that is only good for 104 Amps! :laughing:


I dont have the photo of the inside cover that had the markings.

I was pretty sure it said 25KW, but I could be wrong, maybe it was 25 VA or KVA.


----------



## spark plug (May 5, 2009)

*Clarification of Electrical terms!*



AndrewF said:


> I dont have the photo of the inside cover that had the markings.
> 
> [I was pretty sure it said 25KW, but I could be wrong, maybe it was 25 VA or KVA.]


VA/KVA Volt Ampere/Kilovolt Ampere, Watt/Kilowatt W/KW are very similar terms. Transformers are rated in VA/KVA due to the fact that not all of the output is usable energy because of heat losses (by the transformer)!
What "It said" on the transformer was probably 25KVA.At 240 Volts, it translates to somewhat more than 100 Amps. That is a very basic (small) service that can adequately serve a 1 family house!:yes::no::drinkon't Drink and Drive!!!


----------



## AndrewF (Dec 29, 2008)

Hmmh, I'll go see if there are any other markings on it now.

Nope, nothing useful.

Just that primary is 7200 and secondary is 240/120.

I am sure it does more than 100 amp service as I upgraded to 400.

I hit over 100 amps sustainable at times during the day.


----------



## Red Squirrel (Jun 29, 2009)

Wow that's a lot of power!

Just out of curiosity how much does it cost to upgrade service? I want to upgrade mine to 200 amp eventually. I'm on 100 amp and the panel is FULL! I will need to go through and see if I can consolidate circuits. They probably did silly things like dedicated a whole breaker for the light bulb in the laundry room, and stuff like that.


----------



## kbsparky (Sep 11, 2008)

Andrew, Andrew, Andrew!! 

My point in all this is that many times we go off the deep end thinking we need all these Amps, etc. But the power company's transformers and lines that connect to our houses are much smaller than we realize. 

They are not bound by the rules of the NEC and can set their own standards. But remember that they are responsible for their equipment, and have to fix it at their expense when it fails.

A 25 kVA or kW transformer is pretty much standard size for a service to a dwelling, and sometimes one such transformer will supply many houses. It can operate at 100% capacity, and much more than that for a short time if needed. 

A 400 Amp service operating at full capacity would need at least a 100 kVA transformer to handle such a load. And, if it was a continuous load for any length of time, the POCO would probably install a 167 kVA unit. We recently upgraded a poultry farm from 400 Amp to 800 Amp due to them adding additional loads, and pushing the limit on their 400 Amp service. 

Here is an example of what a large continuous load can do your equipment:










As I have previously stated, if you really think you need that much capacity, you probably can't afford the bill. :whistling2:


----------



## AndrewF (Dec 29, 2008)

Do I need continuous 400 amp service? No.

Do I need more than 200, potentially yes.

I looked back at my usage for this past winter. I will pull ~125 amps continuous when the HP is running and the resistance heat is engaged. (HP is around 30 amps and heat tape is 86). The steady state of my house is around 5 amps all the time.


Attached is a graph of today's demand. It was 70 out, so the A/C only came on once.

The WH seems to draw around 45 amps when it is running.


----------



## Red Squirrel (Jun 29, 2009)

AndrewF said:


> Do I need continuous 400 amp service? No.
> 
> Do I need more than 200, potentially yes.
> 
> ...


Those graphs are neat, what type of setup do you have that generates these?


----------



## Leah Frances (Jan 13, 2008)

I've enjoyed this thread. Service entrance intimidates me, so I am duly impressed. LOVE the graph. 

As to the capacity: When has anyone ever wanted LESS power than they had? 

When we bought our house the POCO discovered that a lazy POCO employ shortcutted the line across my neighbor's property - rather than in the utility easement. At least they admitted it was their bad. They had to put in a transformer and re-run service to the house - upgraded to the transformer for free! Can't wait till I have the cash or the cojones to take the house from 200A to 400A. MORE POWER!


----------



## AndrewF (Dec 29, 2008)

See this thread for some history on it.

http://www.diychatroom.com/f17/hvac-monitoring-34610/

I use Cacti for the graphs, and custom code for the rest.

http://enviro.onlinedesk.net


----------



## kbsparky (Sep 11, 2008)

Wow: 45 Amps for a water heater? Do you have simultaneous operation of the heating elements?

Most water heaters rated at 4500 watts draw about 18.75 Amps. Dual 5500 watt elements would draw 45 Amps or so ....

That 25kVA transformer can handle loads such as you have posted just fine. The times when you are over the 100 Amp threshold are short, not enough to flinch such a transformer.:whistling2:


----------



## AndrewF (Dec 29, 2008)

kbsparky said:


> Wow: 45 Amps for a water heater? Do you have simultaneous operation of the heating elements?
> 
> Most water heaters rated at 4500 watts draw about 18.75 Amps. Dual 5500 watt elements would draw 45 Amps or so ....
> 
> That 25kVA transformer can handle loads such as you have posted just fine. The times when you are over the 100 Amp threshold are short, not enough to flinch such a transformer.:whistling2:


I am speculating the WH draws 45 amps based on when it is on and the current draw at the time.

I'll try to put the clamp on meter on it sometime and confirm that. The WH was here when I moved in, only about 1 year old.


----------

