Anyone that gets a transfer switch that controls the whole panel, beware that if you are tying in before your main breaker, the power is almost unlimited from the pole transformer. These transformers are fused on the primary side (usually 7200 - 25000 volts) and can supply hundreds if not thousands of amps on the secondary side if a dead short were to occur. So please if you are working anywhere in your panel remember there is enough power in there to create quite a severe explosion if you short something. Some of the older breakers in panels were not the best at tripping as fast as they do nowadays. The longer it takes for a breaker to trip, the more damage that can occur, once an arc occurs the area around the arc becomes a conductor as well because of the reaction that takes place. I can say that as I have a 600Volt contactor short out in front of me and explode. Luckily I had my safety glasses on but I got hair singe of the backs of my hands and arms. This was only a small contactor (good for 10000 watts), but the protection that was suppose to be protecting it failed, the circuit ended up tripping a 600amp breaker back at the main distribution because a thermal overload and a 70 amp breaker did not have any ground fault protection on them. I could go on with more detail but it is pointless to most people if they don't have the electrical theory behind them. For the first few seconds I thought I was blind from the fireball that circled my head, but then realized it was because the main breaker had tripped killing the whole plant. All I could see for the first few seconds was a yellow circle in front of me. This I realized was the sun shining in through a window. Anyhow, babbled enough, hope it gets the point across about safety around electricity. Oh yeah, the reason for the short was that a contract electrician that we hired to replace a wire harness had crossed a couple of wires that we had assumed he had checked. There is where I made my mistake, was by assuming and I got caught and was lucky to survive. Our plant is only small but can draw 2500amps at 600Volts (almost 2.6 million watts of power.
Steve