Syed... thanks for your replies.
1) I'm surprised that the local city ordinance does not cover this. Many local electrical codes across the United States are due to what the local fire departments require.
2) If installing a sub-panel, I would recommend that the 2 main panels be de-installed and upgraded. Based on the picture, it appears the panel is maxed out and no available space for a feeder breaker and future branch circuits. Not sure how many amps you currently have for each panel, but the current NEC requires a minimum of 100 amp service for each main panel. Without knowing all of the existing loads, I would recommend that the service be a 200 amp service each and run a 100 amp sub-panel off of each 200 amp main. This will provide and allow for any future growth requirements. Especially in the event of upgrading the stovetop to a 240 volt stove or a 240 volt Air Conditioner.
Although, you could possibly get away with a 100 amp main service panel and run a 60 amp sub-panel. Thus (2) 100 amp mains and (2) 60 amp sub's. In either arrangement you would still have the 2 separate meters, 2 main panels and 2 sub's. Either way, load calculations by the licensed electrician should be performed to ensure the required amperage on the main and the sub's and allow for any future growth requirements.
If installing a sub-panel, the feeder circuit must be a 4-wire circuit, ie, 2 hots, 1 neutral and 1 equipment ground. At the sub, the neutral bus bar must remain isolated from the panels metal enclosure. The neutral always remains as floating in any sub-panel installation.
3) Seimens, Cutler-Hammer, Square-D and GE are all reputable panel manufacturers. I like the Seimens model the most since I am familiar with them, although they are all good panels. For fire department purposes, I would recommend that the sub panels be a main breaker type and not a main lug type. In the event the fire department would ever need to disconnect service on the sub-panel room, all they need to do is turn the sub's main breaker to OFF instead of locating the feeder breaker in the main panel as the means of disconnect. I would label each sub-panel with the respective unit number on the building.
4) If considering a meter bank, go to your local electrical supply store. Most likely the electrical supplier will be a distributor for Milbank metering equipment. Here is a link to Milbank's web site for Multi-Position meter sockets. I would recommend a Multi-Position meter socket with its own individual main breaker disconnect. Milbank is a very common meter socket manufacturer and very reputable company.
5) The use of inside aluminum wiring is at many times considered as a potential safety issue since many electricians improperly installed aluminum wiring and did not size the conductors accordingly, not using AL rated devices for switches, receptacles, etc and not using proper AL wire nut splices. I would highly recommend that a qualified licensed electrician inspect these.
Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.
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