  The $TH\epsilon\mu$ formalism was developed to study nonmetric theories of
gravitation. In this letter we show that theories that violate Local Lorentz
Invariance (LLI) or Local Position Invariance (LPI) also violate charge
conservation. Using upper bounds on this violation we can put very stringent
limits to violations of Einstein Equivalence Principle (EEP). These limits, in
turn, severely restrict string-based models of low energy physics.
