I totally understand about derating. I think the original question I posted is being confused. My question basically was how do you know if an existing distribution is becoming overloaded and how do you determine if you can continue adding loads without the risk of blowing the main fuses feeding that switchgear?
What about taking a load check with as much equiptment on as possible, knowing what the load is you are installing and looking at your main to determin if you can handle the total loads?
