What happens when rain over flows in ground pooli t is raining and I have a pump to drain the pool but I do not want to get electricuted?

There is not much point worrying about it. Just wait until the rain stops and if the pool being too full is a problem to you personally lower it after the rain has stopped. On the other hand you could just leave it there and wait for it to subside naturally saving you having to top it up. Some people use floating pool skimmers so that they can take advantage of rain without having to worry about water levels. If you have a salt water pool you may have to check if you need to add salt.