ServiceNomad RV · Knowledge
RV Inverter On But No Power to Outlets
When an RV inverter appears to be on (indicator lights are lit, maybe even a cooling fan is running) but the AC outlets remain dead, it indicates a problem between the inverter's output and the RV's AC distribution system. This can be caused by tripped breakers, failed transfer switches, wiring faults, or inverter internal faults. Understanding how inverters integrate with your RV's electrical system helps you diagnose why power isn't reaching the outlets.
Transfer Switch and AC Distribution Basics
Most RVs with inverters use a transfer switch to route AC power to the outlets from either shore power or the inverter (but never both simultaneously). When shore power is disconnected and the inverter is on, the transfer switch should automatically route inverter power to selected circuits (typically the outlets, TV, microwave). If the transfer switch fails, is stuck in the shore power position, or has a bad relay, inverter power never reaches the outlets. A technician will locate the transfer switch (often near the converter or main breaker panel), inspect it for proper operation, and test voltage at both the input (from inverter) and output (to outlets). If the transfer switch has voltage on the input side but not the output side, the switch has failed or is not transferring properly. Transfer switches can be mechanical or electronic, and both types can fail.
Breakers and Inverter Output Circuit Protection
Inverters often have their own AC breaker on the output side, separate from the RV's main breaker panel. If this breaker is tripped, the inverter's AC output is disconnected and no power reaches the transfer switch or outlets. Some inverters have a built-in breaker on the front panel; others use a standard circuit breaker mounted nearby. A technician will check the inverter's output breaker, reset it if tripped, and test for voltage at the inverter's AC output terminals. If the breaker trips immediately upon reset, there's a short circuit downstream—either in the wiring, at the transfer switch, or in a connected appliance. They'll isolate circuits to find the short before restoring power.
Inverter Configuration and Output Mode
Some inverters have multiple modes or settings that must be configured correctly. For example, the inverter may be in 'standby' mode (where it's powered on but not producing AC output until it detects a load) or 'charger-only' mode (where it charges batteries but doesn't invert). If the mode is set incorrectly, the inverter won't produce AC power even though it appears to be on. A technician will check the inverter's control panel, display, or connected remote control to verify it's in the correct mode (typically 'invert' or 'on'). They'll also review the inverter's manual to understand the specific model's operation. Some inverters require a button press or switch toggle to enable inversion after turning on.
Inverter Internal Faults and Output Stage Failure
If all external components (breakers, transfer switch, wiring) check out, the inverter itself may have failed internally. The DC input stage and control circuitry may be functioning (hence the indicator lights), but the AC output stage (power transistors, transformers, or output circuitry) has failed. This requires internal inverter diagnostics and often results in inverter replacement. A technician will use a multimeter to test AC voltage at the inverter's output terminals. If there's no voltage or very low voltage (less than 100V AC) even though the inverter is supposedly operating, the output stage has failed. Inverter repairs are often not cost-effective compared to replacement, especially for older units.
💡 Prevention Tips
- Test your inverter system regularly (monthly) to catch issues before you rely on it in the field.
- Label all breakers and transfer switch positions clearly so you can quickly diagnose power routing issues.
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