sub-panel question

[homerepairld]

I want to add an additional 120 volt circuit to a bedroom. My house was built in 1979 and originaly had a heat-pump in the attic. This was powered from a sub-panel in the attic that was controlled from a 125 amp breaker in the main panel. Later I had the heat-pump removed and a gas furnace put in, so the installer disconnected a 60 amp breaker in the attic sub-panel and added a 30 amp breaker for the gas furnace. The sub-panel box uses Zinsco type breakers which I found were obsolete. So I want to use the now empty 60 amp breaker to connect a new sub-panel nearby, where I could install a 15 amp breaker for the new bedroom circuit. My question concerns the attic sub-panel. It is connected to the main panel by an AL Type SE Cable Type XHHW 3 CDRS 600 Volts. There are 2 hot leads connected to the sub-panel and then some bare wires that are twisted together and connected to a neutral bar (in 2 places) in the sub-panel. This neutral bar appears to be connected with a screw to the metal sub-panel box. Is this old sub-panel wired properly so that I can use it to feed the new sub-panel and have a properly working ground connection etc.?

[HayZee518]

By code, at least the newer ones, any sub panel needs to have the neutral isolated above ground and an auxillary ground bar installed.
The feeder to this panel needs a four wire cable - two hots, a neutral and a earth ground wire. Hots go to a back fed breaker OR a set of MAIN lugs, white neutral to neutral and the wrapped bare ground to the aux bar. The bonding screw is NOT used.
So I guess in your case - run a four wire to the new sub. Red/Black to the main lugs, red/black to the 60 amp breaker, Neutral and wrapped ground to the neutral in the OLD panel. In the new panel, neutral to the neutral bus, add an aux bar and put the wrapped ground here.
Don't use the bonding screw or jumper.
The romex you connect for your circuit, black to the breaker, white to the neutral bus and the bare to the aux ground bar. When you install the aux ground, scrape the paint off so it makes intimate contact with the box metal.

[homerepairld]

HayZee,
Thanks for the information and I think I will use a GFCI breaker or receptacle for added safety on the new circuit.

[Dancharger]

Hayzee is correct. The only problem I see is that the neutral, by NEC, is required to be run in the same cable as the 2 hots. You can't use the bare wire that is in the cable for a neutral 'cause that is also a NEC violation. You may want to re-identify one of the hot wires as the neutral with white tape at both ends and just feed 120 volts to your subpanel, then you can use the existing cable & not have to put in another wire. By NEC, if your new circuit is for a bedroom it needs to be protected by an arc-fault circuit breaker. Just my 2 cents worth.
Dancharger