rbulsara's response is correct if the neutral is broken between the connection to the service ground electrode and the service disconnect, leaving no ground on the service neutral.
If the neutral is broken on the source side of the connection to the service ground, then there will be a connection through the earth to the source neutral which is grounded at the transformer. You will have a high resistance return path to the source.
L-N loads may work but not properly. There may be high voltage on one leg and low voltage on the other leg. Ground faults may or may not be detected, depending on the earth resistance.
1-If you havebalance loads,the system would work normaly even no grounded points any where .
2- If you have unbalace loads and multiple grounded points are there , the system would work normaly in condition that source neutral is grounded.
3- If the source neutral point is not grounded the system will work with floating neutral point ,it meanse the voltage will shift with respect to the loads impedace on each phase .
4- As I explained single phase loads would work properly if you have balance load on the three phase ,it meanse all single phase loads have the same impedance on different phasese .If not balance also they work but not properly due to shifting of the voltage and the loads may get damage because of the rising of the voltage on one phase and reducing one the other .
With the price of copper, the utility may not have a whole lot of grounds left after the thieves come through.
Even if it is grounded multiple places, in areas with high resistivity soils the resistance of the pole grounds will be orders of magnitude than the neutral conductor.
L-N loads may work. The current that normally returns on the neutral is going to return via the ground connected in the service panel, throught the earth and through the ground at the utiliteis trnasformer.
Now comes the part where they work but not so well. You may get a tingle touching the sink. You may get a tingle touching the case of your toaster. If you have a block heater in your car you may get a tingle when you touch the door handle. "May" is the operative word, it will depend on how the elements are configured and their value (ohms).
Getting "bit" while doing things around the house is one of the clues that you have a bad ground and/or neutral.
