Breaker Box Questions

I am renovating a 1920s home and it was rewired in the late 70s-80s. The is an old 3-phase box that is no longer in use, then there is second a large breaker box that has 40 breaker slots in it (actually it shows on the list 1-40 but many of the breakers have been assigned two numbers so there are more like 20 actual breakers--that brings up a whole other question for later). One place on the box says its a 150 amp max and another place it says its a 200 amp max. The way I understand it, the breaker total should add up to this max (considering 80% usage). Is this right? What I don't get is how is this total supposed to work if the box holds this many breakers even at 15 amps apiece that doesn't add up right. Why would a box hold more than its max at the minimum of 15 amps. My box has a few 15s but mostly 20 and 30 amp breakers. In addition it has two wires connected to about 3 of the breakers (double lugged??). I am going to take some photos of the box and/or draw a diagram today and I'll try to post them. I know that several of these breakers were assigned to 220 AC units which I no longer need and would like to reassign, but in the process, I want to make sure it's all in compliance and safe. Many more questions to come--this house is a case study for everything under the sun--my boyfriend calls it the money pit.

The sum of the actual breakers has NO meaning AT ALL with regards to service capacity and calculated load.

Thanks. That's what I was thinking. I think my friend misunderstood something he read.
Now for the next question. My box has 24 actual breakers. The first 4 on each side are shown on the map as one number each (see image below) then the rest are numbered 5/6, 7/8, etc. If a spot for the breaker has two numbers assigned to it by the original box map, does that mean that there can be two wires going into the breaker. See yellow circles where the city inspector glanced and said I had to fix the double lugging. If this is not the case, why would there be two numbers assigned to each breaker? What does this mean? Also, what is the difference between the first 4 on each side having a single number and the rest having two numbers?
(Doesn't look like the image I included worked so I have now put it in as an attached jpg

The spaces with two numbers are slots that will accept "skinny" breakers. They are two separate breakers that fit into the spot one "fat" breaker sill occupy.

Yes, with regard to that brand of breakers, double tapping is illegal and should be fixed. If there is no room, and there is no problem of breakers tripping, the simplest solutions is to splice a tail of wire to the two on the breaker. Then put the one tail on the breaker. Make sure the tail is the same size as the other two.

What about changing the big breaker and putting two skinny ones in its place--then each wire would have its own spot? Is that safer than the tail?

Yes, that would be better. Even better than that would be to replace that old FPE (brand) panel all together.
Do a web search for "Federal Pacific Electrical" and you will see what I mean.

I did do a search because the faceplate that covers the breakers is missing--the main cover is there though. I noticed concerns about the FPE stab-loc (which had no screws) but I haven't seen any concerns about the regular screw type of breakers.

Federal Pacific breakers have a high rate of failure. The connection to the power bus is barely adequate. I have seen them burned almost completely off.

Myself, I'm a SquareD fan.

OH! You think that Stab-loc means that the wires should stab in like a stab-lock receptacle.. That's not the case, Stab-loc refers to the point of connection between the breaker and the panel power bus. The wire still attaches under the pressure of a tightened screw.


Here's a picture of a Stab-loc panel;



It looks to me, exactly like yours.

This is a link to identify the panel;

http://www.inspect-ny.com/fpe/fpeid.htm

This is the homepage for that site;

http://www.inspect-ny.com/fpe/fpepanel.htm

The fire hazard is real.

My advice is to get rid of that panel. As a Home Inspector I see many of these panels with scorch marks and loose wiring.

To many issues with this panel to fix. Recommend replacement due to saftey and fire concerns is no joke.