Residential electric question

Our home's electrical system is a clusterberkeley far beyond the scope of this post, but I'm trying to figure something out.
 

There's a ganged dual-40amp 220v breaker that runs one leg of the tankless heater in our master bath. It used to trip occasionally (but not the other circuit) which I presumed was due to our ridiculously low water pressure(we could tell when the neighbors flushed their toilet - no lie), however the city recently finished running all new water lines & our pressure hasn't had any noticeable fluctuation since the. Unfortunately the breaker seems to be tripping more & more frequently. 
 

Here's where things start getting weird...

It's the bottom-left breaker than needs replaced. See the "house main" breaker? That runs out the bottom-right of the box & into a small panel in our kitchen cabinet that then feeds the rest of our house - except the master bedroom addition(which is where the water heater is located).

The top-left breaker goes to a panel in our bedroom & runs the master addition, except the water heater, which is run off the two breakers on the bottom left. 
 

I pulled the cover off & I don't see any way to kill power to these breakers without calling the power company. Does that seem correct? If so I'm calling an electrician to swap the breaker because I'm not comfortable doing that live. 

I agree this looks odd and appears to have no main breaker/shutoff. 
 

Looks like you could "have an electrician" pull the meter shroud and remove the meter. Replace the breaker then call the utility and have them come back out and "seal" the meter again (new clip on the lock). I've done that before and the utility didn't give me any grief. I've been told that some utilities don't like people doing that.. because spark pop bang. 
 

It'll cost a lot more but it'd be beneficial to have an electrician install a main shutoff between your meter and panel. 

That's a pretty bizarre setup. 

If you were local I'd stop by and pull the meter for you, but since you aren't call the power company and ask them to. An electrician may not be willing to pull the meter since that technically belongs to the power company. 

You only need about 10 minutes to swap the breaker and they can reinstall it. 

The power company may require an electrician to do the work though. 

When i put a new panel in i called the electric company and told them i was pulling the meter and would need it resealed.  The said good deal and came out a couple days later with a new tag

i wouldn't hesitate to pop that breaker out with the panel live though, you're not using tools or prying on live stuff

Some electric companies are fine with you cutting the seal and pulling the meter, some are not.  I would call the company and see what they say.  It's not a big deal to replace a breaker in a hot panel, just don't touch the bus bar or the main lugs.  What type of tankless water heater do you have?

Thanks guys! I'll try a couple electricians & see what they say, if it's a ~$100 service charge plus the breaker then I'll let them do it. We can't be without power for any significant period of time though, so pulling the meter then having to wait for the power company really isn't an option. 
 

What I didn't mention was the leg that runs into the small panel in our kitchen, then runs into a larger panel in the rear addition on the house. And runs from that panel to another panel in the garage. And runs from the panel in the garage to a panel in the shed. And runs from the panel in the shed to the gazebo...
 

In reply to rustyvw :

I forget the brand it's labeled as, but when I looked it up shortly after we bought the place I discovered it was manufactured by Bosch. I absolutely hate it, and would gladly replace it, but the only option that wouldn't require significant remodeling of this end of the house and not lose any closet or bathroom space would be installing an electric tank water heater in the attic. 

Pete, when you pull the meter you just stick it back in and you're done, they just come out and clip a new tag on(that little clear guy below the meter)

What's the unmarked 40a 220 that is on go to?

Edit: or do they both go to the water heater? 80amps holy E36 M3.

That is definitely an odd one for a residential. It's basically following the "6 switch rule" part of the NEC which allows for up to 6 switches serving a single structure - indicated by the label "Each Handle Serves as a Service Disconnect".  Hard to say why it was done that way without seeing the house panel inside, but I can think of a couple of reasons - likely load related after reading the post about all of the sub-panels.

Most residential panels use push-on breakers which are pretty straight forward to R&R on a live panel, but I would hesitant to ever recommend one do it without knowing their electrical skill level.

I would be somewhat concerned about why the breaker went bad.  Or if it's actually the breaker that is the problem and not the wiring.

Robbie said:

What's the unmarked 40a 220 that is on go to?

Edit: or do they both go to the water heater? 80amps holy E36 M3.

People often don't realize how much power is required for tankless water heaters.  80 amps isn't unusual, some can require 140 amps. Same sort of deal for gas tankless water heaters as well, they will often require an upgrade to the gas service to operate properly.

Back to the original post:  As mentioned by Ian, this one uses the six disconnect rule so there isn't one single main disconnect.  They are pretty unusual but you still see them in older installations (I'm not quite sure why, but electric panels on the house exterior tend to be seen only in southern climates as well.)  It will require pulling the meter in order to work on it safely, but if all you're doing is replacing the breaker that will take just a few minutes - you may be able to get someone from the electric utility to pull the meter, then quick replace the breaker while they wait, and then they can reinstall it and be on their way.  Maybe offer service guy a cup of coffee and a donut.  

Thanks guys! It's good to know about the 6-switch rule too. 

In reply to Ian F :

There definitely was a correlation between the water pressure dropping & the breaker tripping, prior to our pressure being fixed this fall. It also seems to trip more in cooler weather, which I think is due to cooler water temps - down here the water lines aren't buried very deep, since there's no hard freezing like up north. In the summer our tap water is often near 80*. When we've been out of town for a few days it would also trip more, I'm guessing due to air in the lines?

In that case, I might wonder if the lack of water pressure is causing the water heater to operate when dry, which could cause it to overheat and pop the breaker.  But I cannot claim to know how water heaters react under those circumstances.