I think 12/2 is a bit small for a 100' subpanel feed to an outbuilding. I
would have suggested 10/3 as the cable of choice for a light load such as
yours.

It is a code violation and a potential safety hazard to have the grounds and
the neutrals connected together in a subpanel. Buy an appropriate ground
bar for your panel and install in the subpanel and relocate all of your
ground wires to it.

You do need to install at least one ground rod for your outbuilding and
connect it using at least a #6 wire to the ground bar in your sub panel.


John Grabowski
http://www.mrelectrician.tv



"B. Adams" wrote in message
. ..
Recently I had a breaker box installed in an outbuilding (Homeline, 70
amps
max, with 2 20 amp breakers). Power is supplied via an underground cable
from the main fusebox in the basement of my house. The distance is around
100 ft and the cable is 12-2 w/ground. I wired the buidling myself
(four circuits, 2 per breaker). The circuits supply 1 light and 1
receptacle in one room and 1 light and 1 receptacle in the other.
However,
as there was no ground bar, I tied all the grounds with the neutrals on
the
neutral bar. A bonding screw was included but not used. My questions:

1. Does the NEC permit this? Is it safe? (I know that tieing
neutral and ground together on a subpanel in the same structure is a
no-no.)

2. Should the building have its own ground rod? There are no
connections between house and building except for the underground feed.