</font><font color="blue" class="small">( Made sense to me only because I thought water and electricity always called for a GFCI outlet or circuit breaker.)</font>
A circuit breaker and a GFCI (Ground Fault Circuit Interrupter) are 2 different devices. Some circuit breakers have a GFCI built into them but they are still separate devices and perform 2 different functions.
A circuit breaker is there to protect the wiring from a short circuit, like when you accidentally drive a nail through 2 wires and they are shorted together (Am I the only one who has ever done that?). A thermal/magnetic device in the circuit breaker will cause the breaker to trip at a preset amount of current draw (i.e.: 20 Amperes). A circuit breaker will NOT trip at less than the preset amperage and a human being will be dead long before that amperage draw is exceeded. A circuit breaker is intended to prevent fires in case of an electrical short. It's secondary purpose is to protect equipment from being damaged by the short circuit.
About 1970 GFCI's were invented to protect people from electrocution. A GFCI constantly monitors the amount of current on each leg of a circuit (hot wire and neutral wire) to insure that it is equal at all times. If the current draw on the 2 wires becomes unbalanced the GFCI will trip. The trip point for the difference in current is about 5 milliamps.
If a human grabs a hot wire a portion of the electricity will pass through the body to a source of "ground", such as a metal water pipe. Once that amount of current exceeds about 50 to 100 milliamps(?) it can cause muscle spasm. If the current is going through a critical muscle such as the heart the heart will stop, thus "electrocuting" him.
The National Electrical Code started mandating GFCI's on specific circuits in the early 1970's, starting (if memory serves me) with outdoor outlets (if memory failed me it started with bathrooms).
As the NEC was updated every 4 years they added more areas that had to be protected by GFCI's based on the areas where electrocution was most likely to happen.
Normally, a house is "Grandfathered", meaning the house must only meet the NEC that was in effect at the time the house was built but since bathroom sinks were where most electrocutions occurred inside the home that it is the one area I know of where building codes require that GFCI's be installed in existing homes regardless of when the house was built. Personally, I believe in retrofitting my own home with GFCI's even though it is not required by code, they are just too important and are not that expensive. My wife, me, and the grandkids (most of them anyway) are well worth the $8 a GFCI outlet costs.
Please do NOT ever replace a GFCI with a standard outlet!! GFCI's are there to save your life. If you have a GFCI that is tripping there is a problem that must be corrected. It is possible that the GFCI is defective, but most likely there is a low level current leakage somewhere in the circuit.Replacing the outlet with a standard outlet may cost you your life!
Sorry to be so long winded on this post, but GFCI's really are critical to saving human lives.
I may not be correct in some of the numbers above since I have been out of the electrical trade for many years, but I held a Master Electrician's License in Dallas, Texas for about 20 years so I am very aware of the hazards of electricity.
Perhaps someone who is current on the NEC will address the GFCI/sump pump. Personally, I see no reason NOT to have a GFCI on that outlet and would sure want one if I had a sump pump. Sticking my hand in water that has an electrical appliance running underwater seems to be to be a prescription for trouble if the pump has a problem.
Bill Tolle