Looking to get some people involved that are more experienced with power than I am.  I'm currently in the process of finishing the basement of my house and the power discussion has come up again.  The house currently sits at 2500 sq. ft and will be around 3300-3400 when the basement is done.  

Some undetermined day in the future, I'm looking to get an electric car, put in an electric brewery, and add some miscellaneous circuits in my workshop.  Last year I added a 70A circuit for my hot tub and I was concerned about popping my main breaker with just that but I don't cook a pair of roasts, do laundry, heat the house and go for a soak all at the same time.  

What I find to be alarming is that the transformer in my yard is only a 25kva unit.  Since my house is all electric, the heat alone in the winter pulls around 20kw right there.  I'm also, as far as I can tell, not the only house on this transformer.  There's two others on it.  It might explain why my voltage fluctuates so much.  I believe that originally my house was supposed to have gas heat but ended up being all electric.  The other two houses are gas.  It seems like the transformer in my yard is likely undersized for my power needs in the future (or I would have to assume it is).  I suspect I can probably get away with 200A service as the power I would need would be very momentary and I'm never doing two things at the same time.  Knowing that the transformer in my yard is only 25kw is the concern.  God forbid if I wanted geothermal or tankless hot water heater.

My questions stem here - What are my options to getting service upgraded to the house if the transformer is over capacity?  Am I responsible for helping pay for a new transformer / additional service line to the house?  I feel as if an argument could be made that the transformer is too small for the needs of the three houses.  

You need to contact you power company and tell them what you wanting to do and they can advise you from there.

POCO is usually required to serve the load presented.

Load diversity makes adding up breakers not a useful exercise.

Ok first, are you considering getting gas service for anything?  Heating with gas is always nice (i have gas heat of course) but cooking is great too and plenty of other stuff.  The major upfront cost though would be the plumbing to run the gas lines in your house and the purchase of any appliance to use it.  But if you do go this route it would take a load off the electric service, plus gas service practically never goes out even when the electric does.





With all that said, I think most electric car charging stations typically use a 240v, 30A circuit.  I have no idea what a brewery uses, but as far as workshop circuits, again most welding stuff I know of would use between 30A-50A.   To give you an idea for comparison, I have a 200A service.  I have an electric tankless water heater that uses 3 independent 60A circuits.  Then throw in my 5 ton a/c unit with a 50A circuit, things COULD get interesting but they haven't yet.  And yes, I've had the water heater + a/c + electric oven and other stuff all running at the same time and not tripped the main breaker yet.  I've amped the water heater a few times and its usage isn't really that bad, but then again I guess our water demand isn't that much either.





 

I do know that a 400A panel is considerably more expensive than 200A.  We have a 400A service on our home and I was looking to replace our old Zinsco main panel...which are not desirable.  But a new 400A panel was $$$$, I even debated going to a 200A modern panel since it was cheaper...but ended up leaving things as they are.  I do know our power company said they would run the new 200A service to our home for free if we wanted, then an electrician would need to complete the install from there.

Any ideas on how to determine what rating the transformer serving your neighborhood is?  Should I look for some conspicuous label or something?  I have a pretty good idea where mine is located and it's always given our neighborhood some fits.

Usually there are some large numbers on them that specify KVA ratings. Commonly 25 and 50 in neighborhoods.

Start complaining and demand a power line monitor.
Encourage neighbors to do the same thing.

How old is the neighborhood?

POCOs do often do not bother upgrading unless they get complaints.
They have no real way of knowing if the supply is getting ratty.

Just your HEAT pulls almost a 100amps?

I would be looking into something different for heat maybe some invertor driven heat pumps

I know mine pulls around 16kw when the heat strips turn on.

Yup - the breakers in my panel for just heat alone is 120A worth of breakers.  Obviously they're over rated for some capacity but the heat strips in my furnace use 20,000 watts of power when they kick on.  I can turn them off, but when it gets to be in the teens the heat pump starts losing its efficiency real bad.  

Gas at this point is not an option I would like to explore.  I've heard many horror stories about their service locally.  Some people's gas bills being around $350-400/mo during the cold months.  Basically the gas company has a monopoly on the development I live in and it lets them gouge.  My house and my neighbors house are the only ones on all electric.  He is on a separate, larger transformer.  He has 400A service, (2x 200A panels in the home).  His house was built after mine and was likely planned for to be all electric ahead of time.  

I found out the rating of the transformer and its specs by emailing the placard with the model number / stock number / serial number on it to the manufacturer.  I think next week I'll give the power company a call and see what they have to say.  I'm likely to get looped into a non-technical person that has no idea what I'm trying to accomplish.  I'm not even sure they'll talk to me unless I'm an electrician.

Car charger I'm looking at needs a 90A/240V breaker, brewery would use either a 30A@ 240v breaker / plug depending on the style of brewing you want to do.  Probably another couple 20A @120v circuits for my shop and finished basement area.  Maybe a circuit for a welder at some later date.    

Really, a second 200A panel is what I'm going for.  This solution would be acceptable but I'm sure the transformer isn't going to cut the mustard.  I'm not sure how it is right now to be honest.  
Cost isn't really a concern.  This fits under the buy once, cry once category.  I don't want to have to tear up my house to add it in later after the basement is finished.  Just trying to figure out what my responsibilities are as a homeowner.

I would replace the meter can with one rated for 400 amps and then just use two 200 amp panels

I doubt the current conduit and cables to the house are the correct gauge for 400a service to the meter. They would either need to reinstall the existing run to support 400a or likely just another 200a run to a second meter and panel.

I'm sure OP is aware of that but his question seems to be is he on the hook for a new transformer and lines to the house?

When we remodeled our kitchen in 2007, we went from a 100A screw-in fuse panel to a 200A breaker box. That required a new run from the pole to the house. We had to pay for that. The electric company handles everything on the pole, but once we left the pole it was our responsibility. Luckily, our run was only about 75 feet and it's suspended rather than buried so it wasn't too expensive.

Hell have to pay for the service run and installation for sure, every company handles things differently hard to say on the transformer, there might be some upgrade cost there if they needed to upgrade to a 50 KVA, wouldn't expect it to be much.  There not hard to deal with be ten times easier to give them a call if it's something your actually serious about doing and paying for.  OP a 25KVA can handle a lot of load no point in them changing it out if there no existing power issues, it's not like everyone with a 200 amp service ever pulls close to that or you and your neighbor are drawing maximum load at the same time.

20 kW is only about 83 amps at 240 V.

Look for the nameplate on the heating elements.

Resistive heat draws more until the elements heat up to operating temperature.
Then they draw there rated output power.
120 A at 240 V is closer to 29 kW.

A pair of 200 A panels is far more common than using anything larger.
200 A service is very 'standard' so there is a huge manufacturing volume.

I have seen 100 A panels actually cost more than 200 A panels.
Even 'no main breaker' panels can cost extra since they are not used as much.

I have purchased 200 A panels with main breakers, removed the main, closed up the hole (screwed in place sheet metal scrap), then back feed one breaker in the panel (that breaker must be fastened in place) and spent less than a smaller panel.

I generally try to use the same type of panel for all the panels.
Makes sparing breakers a lot easier.

Brand availability varies from area to area.

 

How much load are we talking?  Let's say I start pulling a full 20,000 watts for a few hours while my car is charging.  Then my other two neighbors start a load of laundry and their hot water heater kicks on and whatever else.  Let's just say we're at 35,000 watts for a bit.  At what point does the transformer fail, give up, whatever and the power company has to fix it?  I'm sure its fused, so maybe they just come out and replace fuses until it happens again.  Although on the other hand I suspect that is uncommon and they would start scratching their heads.  Just trying to get an idea what its overload capabilities are.

Voltage starts to droop.
Just like any other overloaded transformer.

Eventually it will fail from repeated overheating but they have a lot of margin.
The fuse on the line side is for catastrophic failures.

It's fused with a bayonet fuse likely for faults/lighting strikes excessive load usually doesn't blow them they fail and the internal current limiting fuse burns up and the then replace it with a new one not a lot of trouble shooting involved, when a fuse blows on a urd transformer it's typically a disconnect the secondary side to differentiate between a cable fault or a bad transformer.  Likely then if it was determined it was overloaded they'd install a 50 KVA.

Your best bet if your serious about this is to get the ball rolling, utility won't have a problem talking to someone serious about the work but you need to get your ducks in a row first, they'll handle there equipment and however they particularly size there equipment every engineer and company is going to be different no sense in worrying about stuff you can't control they'll handle there part.  Your right you might get looked off a bit because your not an electrician because they know when an electrician calls the work is going to be done vs some random Joe callings about what ifs.  If your serious and have the stuff lined up and ready for them to do there work they'll get what they need to get done.