A better question would be why are your bulbs burning out? It might
be that the safety features is actually doing its job and preventing a
meltdown. 2500 bulbs belches quite a bit of heat. Before you disarm
the safety features, do some calculating:

Each bulb burns about 1/2 watt. 2500 lights burn about 1250 watts,
most of which goes up in heat, not light. That's quite a bit of heat
that has to go somewhere. My guess(tm) is that your tree is
overloaded with lamps and they are blowing because they're getting too
hot.



No way, incandescent lamps will work fine in environments hot enough to burn
the insulation off the wires. Unless the tree is on fire, heat will
absolutely not cause these lamps to fail. This is not rocket science, bulbs
burn out, connections in sockets get bad, series wired lights are notorious
for problems like this. Additionally, as each lamp fails and shunts, the
voltage across the remaining lamps increases and if left unchecked they'll
start to burn out too. More than once I've had this cascade in smaller
strings to the point that every lamp burned out until the fuse in the plug
opened.