Here are a couple of additional photos.
Marc, the exterior discos were a 20 amp and a 30 amp.
I thought the service ampacity was based on the service conductors size entering the service mast.
There were only two panels in the home and they both looked the same.
Thanks again for the help.
Something’s not adding up here.
Do those outdoor disco’s feed the tennant panels, such as the one you show in the first pic? There are #12’s or whatever leaving the breaker in the outdoor disco’s, but #4’s entering the tennant panel. Perhaps the meter is double tapped on the load side? There’s just not enough info yet to say for sure what’s going on. I guess that’s about as deep as you get into things anyhow.
Marc,
I should have investigated further. I did not trace what the 20 and 30 amp exterior discos fed. I was thinking the water heaters.
There were laundry/utility rooms on the end of both units that the realtor did not have a key to. There were windows that I looked in. I did not see any additional panels anywhere…just the one in ecah unit.
That would be my guess also, or window a/c receptacles or a bit of baseboard heat. That would make me think that each meter load side is double tapped. No way to know that for sure from your standpoint, obviously. I suppose at this point this is just interesting conversation, rather than something you seriously need to sort out yourself. If those are full-size conductors going from the each meter to each tennant panel, then you may well have a 100 amp capability at each tennant panel. Regardless, then you’d have 6 disconnects inside each unit, and one disconnect outside each unit. They need to be grouped, and that’s 7 moves of the hand. Only permitted 6 to kill the whole building. Take the whole building into account, and you might have 20 disconnects, all located at various places. What a mess.
Marc,
I will put unknown for the service ampacity.
They need an electrician to upgrade the entire system. There were a couple of double tapped breakers, one was a 50 amp with a #10 wire, no GFI protection and conductors lacking conduit in numerous locations.
Thanks for the info and help Marc 
I sorta hoped you would. That whole thing has been wrenched on too many times by whoever. The fact that there appears to be a zillion disconnects, all over the structure, to make the whole palce dead is the primary concern in my mind. You saw the place, however, so there might be bigger issues. Pretty easy to convince people it needs attention anyhow, when you direct them to FPE information on its own merit.
Marc,
Thanks again for always sharing your knowledge with us. You post have helped me numerous times…thanks again.
Hi Matt, as you know you really needed all the info as to conductor sizes, but frankley you have lost nothing as there are several other conditions present that should dictate a review of the system by a licensed (or better still competent) electrical contractor.
On a realistic note, with most even smaller properties down here having electic HVac, water heating, cooking and regular branch circuits 60 amps starts looking a bit “thin” when in doubt a load calc needs to be done, most small appartments and condo conversions will need 100 amp given the potential loads.
Regards
Gerry
Gerry,
Thanks for the help. The units did not have central air. The whole system needs to be upgraded though. There were also numerous defects and safety issues.
I thought the best way to tell the service ampacity was to look at the service conductors entering the mast or weatherhead. These looked a bit smaller than a 100 amp.
Hi Matt, in very many cases the utilities service drop potential exceeds that of the distribution system, my own home has 200 amp service, but conductors between the “drop” and the panel are rated for 150 amp, the panel is rated at 200amp max and the main disco is 150 amp.
What is the available amperage? and why?
Regards
Gerry
Gary,
Your service would be 150 amp. I chose this because one should go with the weakest link which would be the 150 amp disco and conductors between the drop and panel…correct?
Gerry,
In the case of the duplex i inspected today the wires entering the service mast looked to be #4 aluminum. I thought wires would be undersized for a 100amp service.
The more I learn, the more I learn how much I do not know:)
Thanks for helping me.
Correct, always go with whatever could become the “fuse” the weakest component is the weakest link.
Ain’t this a great business, we all learn every day.
Regards
Gerry
Gerry,
In my original post titled (60 Amps?) did you see the size of the service conductors going into the mast? They appeared to be a #4 wire or smaller. So would that be the smallest link to base the ampacity to the unit by?
Thanks in advance.
Hi Matt, that would be one of the indicators, however as Marc said in the other post you stated that the outside disconnects are 30 amp, if those are feeding the interior panels then the max amperage to each unit is 30 amp.
If you are correct about the sevice entrance being # 4 Aluminum then the maxium amperage to the structure can’t exceed 60 amps
Regards
Gerry
This is a great learning tool. Love NACHI
The ampacity rating for the conductors coming from the pole are not controlled by the NEC. The utility makes their own rules and will decide on the correct size for the load. Often times here the utility leaves the original drop even though the service has been upgraded from 100 to 200 amps.
With that said, the ampacity for conductors in free air is higher than the same conductor in a conduit or sheathing.