Wiring new home into existing outdoor main breaker panel?

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Old 01-29-21, 05:38 PM
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Wiring new home into existing outdoor main breaker panel?

It's been awhile!
FYI the shop I wired up on a sub with help from the DIYers here passed inspection with flying colors
I'm building a home now on a property that has an existing 200amp outdoor panel on a 6x6 post, about 15' from the side of the new home.
I need to essentially setup my new breaker panel inside the home as a sub-panel, but I'm going to need all 200 amps because I'd like to go with a tankless water heater and we're stuck with electric heat in the area.
I don't want to relocate the post or replace the outdoor panel because it has 110V and 220V outlets on it, which I do/will use on occasion as I have a work trailer with a welder and fab tools in it that I plug in there. (Yes I realize I may have to turn the tankless heater off when I'm welding but its not often).
Is it as simple as stuffing a big 200amp breaker into the outdoor main panel and running adequate wire through a conduit into the homes panel?


 
  #2  
Old 01-29-21, 05:42 PM
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Have you picked your tankless yet? Check the specs. 200 amps will likely just barely be enough and may not be enough if you have other large loads.
Do a proper load calculation before proceeding.
 
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Old 01-29-21, 06:02 PM
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I have some tankless candidates picked out, but have not bought one yet. What is saving me is that it's a small house and our state energy regulations require heat pumps, so I'm getting away with about 20 amps for the two 110V units for two of the rooms and about 17amps for the larger unit (220V) for the "great room" These are "starting amps" btw. But I do understand, by the time I add an oven and dryer I'm probably pushing it.
Even if I can't go tankless, I'd still like to have the full 200amps go into the house. Seems to me Square D makes a 200amp Homeline breaker that looks like it would work? See link below.

https://www.graybar.com/homeline174-...ter/p/22069845
 

Last edited by rkcarguy; 01-29-21 at 06:07 PM. Reason: Add link to breaker
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Old 01-30-21, 06:26 AM
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As suggested by Joed I would certainly check to see (before purchasing or deciding for sure to use tankless electric) what your hot water needs will be. Then determine which tankless you will need to cover those hot water needs. Once you do that then see what the power requirements are of that tankless. You may find quickly that the tankless you need won't be able to be handled by your service of 200amps.

Then you will have other appliances like range and dryer will take some power. You will be pushing it. Also welding here and there?

A load calculation is definitely suggested and encouraged prior to doing anything. You would hate to find out after spending money you went in the wrong direction.

 
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Old 01-30-21, 07:20 AM
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Please post a picture of the 200 amp panel with and without the cover so we can see the inside. That way we can suggest options based on your current setup.
 
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Old 01-30-21, 02:31 PM
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Not all 200A panels can handle a 200A breaker. The bus bar is sometimes limited based on the design.

But other than that, no specific issue with running a 4-wire 200A feed to your house.

Though as others have mentioned, definitely research the tankless heater and what it provides. Some folks with electric tankless heaters are disappointed that they can't keep up. Also your location (if the incoming water is exceptionally cold) can affect how well it works too. Granted, some love them... but make sure you've done your research so you know what you're getting into.
 
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Old 01-30-21, 06:23 PM
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I'm building a home now on a property that has an existing 200amp outdoor panel on a 6x6 post, about 15' from the side of the new home.
Is the service on this post or just a panel. I suspect the entire 200 amp service is on this post in which I would just use it as a temporary service pole for construction and plan a new 200 amp service on the side of the house with the panel inside.
 
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Old 02-02-21, 02:55 PM
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The properties were all subdivided in the 1990's and the contractor that did it installed driveways, shared well water, and power to the homesites via 200amp square D outdoor panels. I purchased this from the neighbors who were going to make this one a horse property and ended up moving elsewhere. I will see if I can dig up a picture or take one next time I'm out there. The other homes in the subdivision must be wired somewhat the same way, as I can see that the original panels remain outside.
Regarding the tankless, I did some research on the amp draw and temperature rise compared to our water temperature, and will have to scrap that idea. The units that would provide ample rise and flow from our winter water temperatures required THREE 60amp 220V breakers. I have room for a hot water tank, so it's not a problem, but it would have been nice to have that extra space for something else.
Welders: I have two. A miller 250 wire feed which I use quite a bit, currently I plug that into a dryer outlet with an extension cord but it's only ~33 amps. Then I have an old Miller 430A TIG welder from a shipyard that needs 125amps of 220v if I weld aluminum on high range. I rarely use this, I'll let the projects stack up and then turn off everything inside the house except the lights and weld everything up in one go.
The existing service is buried and it's over 200' from the road/transformer, so I don't feel upgrading to 400amps or adding a second service is feasible.
 
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Old 02-02-21, 06:51 PM
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You say you are all-electric out there but what about propane? Many rural homes have propane for gas which is still less than electric. (Except when gas prices were $4 per gallon)
 
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Old 02-04-21, 01:19 PM
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Yes some of the neighbors have propane, but our electricity is pretty cheap here (rains ALL THE TIME), and therefore we have plenty of hydro power. I will be installing a wood stove though, as power outages are common in ice and wind storms. It's not a big house and I figure using wood heat during the cold times will keep us around $100/month in electricity. My prior home was setup the same way and was 1,767sq/ft, this one is 1,422, but rates have increased a bit.
I cleaned the outdoor panel off and looked it over better, it's actually a Midwest brand panel, 200amp service entrance (Outdoor combo panel and meter base).
It currently has the 200amp main breaker of course, a 60amp 220V breaker and a 20amp 110V breaker installed in it, looks like there is one more space for another 110V breaker left. Breakers for these seem to be hens teeth and expensive ($411 for a 200 amp). Plus, this doesn't have another breaker slot for 220V, so I would have to run a sub from the house for the welder if I didn't replace this service entrance panel.
I called the power company and there is enough amperage available at the transformer for up to an additional 400amp service, but I am not sure how big the wires are that come into the service entrance as I can't and don't want to open that part on my own. I doubt that the wires originally installed/buried would be oversized to let me upgrade to a 400amp panel, but you never know.
I'm wondering at this point if I'm better off to use this service entrance only through construction, install a new meter base on the house, and have an electrician come in and perform a splice and eliminate the Midwest service entrance all together?



 
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Old 02-04-21, 07:49 PM
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In many cases in a dwelling instead of a full-sized 400 amp service, they install 2 x 200 amp services off a single 320 amp meter socket. this is typically much less expensive than a single 400 amp service. Just food for thought.

I am also in the "on-demand water heater is not worth it" camp. If you have room for a traditional tank water heater then I would go that route. I would consider a large Marathon non-metallic water heater.
 
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Old 02-05-21, 01:01 PM
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I'll ask my utility if I can upgrade to a 320amp meter base, seems the best way to begin and they may know according to what is on there now (its their meter), if it's capable or not.
If I could do that, and then install a new outdoor panel along with the one in the house I'd be set.
I have never seen how the connection works for connecting multiple panels to a single service entrance though.
 
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Old 02-05-21, 05:45 PM
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I have never seen how the connection works for connecting multiple panels to a single service entrance though.
Normally the easiest way is to install lugs that accept two wires each in the meter socket and then run a set of conductors to each panel.
 
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Old 02-18-21, 01:05 PM
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So awhile back I had been quoted almost $600 for a second service from the POCO which included laying up to 200' of wire in my trench or conduit. This was going to be for an RV spot (which I have scrapped) and an outdoor panel with plugs for my welders. They replied to my recent inquiry and said it was going to be the same price to upgrade the meter base to a 320 amp IF the existing wiring was large enough to accommodate it.
So, I didn't make much headway on price nor was I able to find out how big the wires are, and I can't open the sealed meter enclosure ugh. Furthermore they didn't answer regarding adding a second set of lugs to the meter base. Maybe that is good that they didn't say no, but thinking more about it if I am parallel wiring in 100amps and 200 amps, I *could* be drawing 300amps from a 200amp meter base with no over-current protection and that can't be good.
I'm probably going to draft a inquiry to L&I electrical and ask what to do there.
As far as needs are concerned, how can I get a 100amp circuit that I can use to weld with on occasion, with the existing 200amp service that will be ok'd by the inspector?
I did read where one installer used a transfer switch (like for a generator) to switch the power from the oven to a welder outlet in the garage and supposedly it passed.


 
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Old 02-18-21, 04:03 PM
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Do you need 100 amps for a welder? All of the welders I have seen are 50 amps max.
 
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Old 02-19-21, 10:54 AM
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For the Miller 250 MIG welder, no, it only uses about 33 amps. But I also have a late 60's Miller 430A TIG welder that came from a shipyard, and it's a beast with 500amps output (peak). 100 amps I can get away with barely, my last shop had a100amp sub and I had to shut down all the lights and just use a LED work light over the table when I was welding thick aluminum. I'm a hobby fabricator and I'd hate to have to give up the TIG welder, it's just too valuable for doing anything from laying down nice tight intricate beads on thin stainless to welding thick aluminum plates that a lot of shops can't touch without letting the parts preheat first.
 
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Old 02-19-21, 03:22 PM
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.

rkcarguy with all due respect I think you need to take a step back and take a deep breath for a moment and think this over more.

You are talking about energy hungry appliances welder, tankless water heater etc and when you need to use each one or the other how to circumvent the need/expenses for a total upgrade to match those needs/demands on your overall electrical service to your home.

rkcarguy I would advise that you first contact the inspector who will be signing off on this project. Discuss with the inspector exactly what he/she is going to look for and expect in order to pass you. I say this because you can look all you want on the Internet for codes but your local AHJ (Authority Having Jurisdiction = Inspector) will have the final word and will more than likely have code requirements above the NEC in effect at the time especially for a project such as this.

Once the inspector gives you the needs for what you want to achieve you figure out if you for a fact know that you can personally handle all of what is expected to pass inspection from the proper materials to the actual installation of everything and I mean everything. If for any reason you feel in the middle of this project that it is over your head and you feel you need a licensed electrician to come help you out I will tell you now that most and I mean most electricians who are worth their weight will not pick up where you left off to help you finish the job. This is because of liability issues on their insurance.

This could end up costing you FAR more money than you ever anticipated.

.
 
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Old 02-22-21, 11:45 PM
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I have wired a couple structures before and they have passed with no issues, but they were always subs, so I have never been into a "service entrance" before. From what I can tell, they are always HOT and I have to have the poco come out to disconnect/connect so I don't want to be into a service entrance lol. I have bagged the tankless idea, as its simply too much amp draw for the water temperature rise and volume I need.
I think my first move is to try to find if my outdoor panel is rated for a 200 amp breaker, and if so it makes the most sense to pop one in the place of the 60 amp and run that as a sub to the house. Then I'm thinking I just bury a conduit when I do my driveway work and back fill and have the poco add another service further down the driveway so I don't have to back the enclosed "weld trailer" clear up the house.
 
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Old 02-23-21, 03:48 PM
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FYI, Midwest is an "underling" of GE, and their panels are listed for use with GE breakers. So at least this opens up breaker choices and availability up to 200amp for less than $100 vs. the OEM Midwest ones which are $400+ for NOS.
 
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Old 02-23-21, 04:03 PM
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Here is my go-to when needing an outdoor main service panel that will not be attached to a building. It has feed-through lugs so you can get a full 200 amps to the house. I will be installing a similar one (Square D QO) at my house this summer so that I can connect a generator.

https://www.homedepot.com/p/Square-D...FTRB/204836396
 
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Old 02-24-21, 11:48 AM
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Thanks for the reply Tolyn.
The property came with this installed on a treated 6x6 pole about 15' from the home:

https://www.homedepot.com/p/Midwest-...oduct-overview

Mine is an older version and has the circuit breakers oriented the other direction, otherwise same brand and appearance. I'll pop the cover off of it tonight and see if it has feed through lugs. It looks like it's listed for them so I may be able to add them if they are missing.
 
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Old 02-25-21, 11:32 AM
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The panel does have feed through lugs, so it looks like I'm set for installing the in-house breaker panel as a sub and retaining the 2 outdoor plugs I've been using.
I will bury a conduit (with a pull rope in it) to the transformer for a future 2nd service, and add that when I'm done with the house and ready to get back into my hobby fabricating again. I think that is going to work the best, I can install another 200A outdoor panel with a welder plug and the RV connection and have plenty of power to work with.
 
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Old 02-25-21, 03:56 PM
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Nice! Sounds like you are good to go.
 
 

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