Gentlemen. of the many hats I wear, electrician is not one of them. My question may be dumb, but here goes. I want to add a sub panel to a 100 amp service. I have seen this done before, so I know its possible. My question is, the existing box id GE. Does the new sub panel have to be GE ? I have an extra Square D and breakers I want to use, but I don't know if I can. Help !