sub panel feed questions

[monkers]

I am trying to get some more power to the "shop" portion of the building Im setting my stuff up in. It is basically a 3 bay garage, with a small (not used anymore) apt over one bay. It has a 150 amp service now, and they have a feed running up to the apt with a sub panel there, think its 100 amps, not sure I will have to look. The apt is empty and not in use. I would like to run 100 amps over to the "shop" portion to a new sub panel (there is a sub panel there, not sure of amps, maybe 40-60???) the panel box in the shop has no main breaker in it, and only has a few spaces, (about 10). I have a panel box to use, 100 amp, with a breaker, and I think it has 20 spaces (not sure, havent looked at it in a while, bought before the divorce lol....its a Square D Homeline or something like that)
The shop is being fed with Al wire, though Im not sure of the size. I would like to upgrade the feed wire from the main panel to the shop. What size and type of wire would I need to use? It is a distance of about 80 feet, its all indoors, and not in any finished walls.
Also, I was told I will need to put 2 ground rods, 6 feet apart for the shop sub panel box. How big of wire should I use to run from the rods to the sub panel box?
Last, I was told that I need to have one bus bar for ground wires and one for neutral wires in the sub panel box. They sell a bus bar that screws to the panel box for this reason a friend said.
Any advice or help would be great guys, thank you

 

[pattenp]

A sub-panel in the same building as the main service panel does not need it's own ground electrode system (GES) (ground rods). The building should already have a GES on the main. If the feeder is all indoors you can use 4 conductor SER type cable. The wire size for 100A at 80' will need to be a minimum of #1 aluminum. Use SER 1-1-1-3.

The grounds and neutrals do need to be separate (isolated) in the sub-panel.

To clarify, this building (3 bay garage) has its own service/meter and is not fed from another building?

 

[monkers]

Correct, it has its own meter and 150 amp panel box. Thank you for your help

 

[monkers]

I looked last night, it has a 50 amp breaker for the shop feed in the main panel box. Which would probably be enough 90% of the time, but I have two lincoln welders, an Ideal Arc 250 and Squarewave Tig 175 and I believe I will need some more power going to the sub panel for them

 

[wyliesdiesels]

Can u switch the apt. breaker to the 50a and use the 100a for the shop feed? Otherwise, u can't swap out the 50a for a 100a if the main is rated for 150a! 50a might be a little small if you're using a welder and a few other things together!

 

[mrb]

Can u switch the apt. breaker to the 50a and use the 100a for the shop feed? Otherwise, u can't swap out the 50a for a 100a if the main is rated for 150a!

says who? you could put 800A worth of breakers in that panel with a 150a main. what matters is the connected load, and to determine that you need to do a load calc.

 

[monkers]

I can switch the apt breaker with the shop breaker, no problem there. Like I said, most of the time 50 amp will be enough, its just when I run the welders that I am concerned about. They are the biggest items I have for now until I move the rest of my equipment in (which wont happen any time soon). Thank you guys for your help

 

[wyliesdiesels]

says who? you could put 800A worth of breakers in that panel with a 150a main. what matters is the connected load, and to determine that you need to do a load calc.

The U/L listing! The OP said nothing about a 150a main breaker just the 2 feeder breakers. That's why I said that. If there is a 150a main, then disregard what I said!

The panel on the place I rent is U/L listed for 180a total(the U/L sticker is even still on the panel). There is 2 90a breakers- one feeding each unit. I would not be able to swap my breaker with a higher amperage breaker because there is no main disconnect ahead of the 2 90s!