What runs on shore power in an RV?

When connected to shore power, an RV’s electrical system can operate all onboard AC appliances and systems, including air conditioning units, refrigerators, microwave ovens, power outlets, water heaters, and battery chargers. Shore power bypasses the RV’s batteries to directly supply 120V AC electricity through a transfer switch, enabling extended use of high-wattage devices without draining battery reserves. Modern RVs typically use 30A or 50A shore power connectors with surge protection and EMS systems to regulate voltage input.

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How does shore power integrate with RV electrical systems?

Shore power connects via a dedicated inlet port using standardized 30A TT-30R or 50A NEMA 14-50 plugs. The power flows through an automatic transfer switch that prioritizes external AC over inverter power, routing electricity to the main distribution panel. Pro Tip: Always verify campground pedestal voltage (108-132V acceptable range) before connecting to prevent equipment damage from under/over-voltage conditions.

When plugged into shore power, the RV’s electrical system operates in parallel mode. The transfer switch automatically disconnects the inverter/charger from the battery bank while allowing AC current to power all hardwired appliances and charge the house batteries through the converter. For example, a 50A service provides 12,000W capacity—enough to simultaneously run two AC units (3,500W each), a microwave (1,500W), and refrigerator (600W) with power to spare. However, RVs with only 30A service (3,600W max) require careful load management to avoid tripping breakers.

What appliances require shore power to operate?

High-wattage AC-dependent appliances like rooftop air conditioners (1,200-3,500W), electric water heaters (1,440W), and microwave ovens (1,000-1,500W) require shore power or generator support. Induction cooktops (1,800W+) and residential-style refrigerators (600W) also demand sustained AC power beyond typical battery capacity.

Air conditioning units are the most power-intensive appliances, drawing 12-16A on 120V circuits. While some RVs have DC-powered vent fans, full climate control necessitates shore power. Electric element water heaters consume 1,440W (12A) but often include propane backup. Pro Tip: Use energy-saving modes on AC units—a 13,500 BTU unit set to “Eco” mode uses 25% less power while maintaining comfort. Residential refrigerators in newer RVs require continuous 120V power, unlike older absorption models that can switch to propane.

How does battery charging work on shore power?

Shore power activates the RV’s converter/charger to replenish house batteries at 10-100A DC while powering 120V systems. Modern multi-stage chargers use bulk/absorption/float phases to optimize lead-acid or lithium battery charging without overcharging.

When connected to shore power, the converter transforms 120V AC to 12V DC, simultaneously powering lights/pumps and charging batteries. Advanced systems like Progressive Dynamics’ Charge Wizard automatically adjust charging stages—bulk charging at 14.4V for fast recovery, then tapering to 13.6V float voltage. For lithium batteries, shore power enables full 100A charging; a 200Ah bank can recharge from 50% in just 1 hour versus 5+ hours via solar. However, always verify your converter’s lithium compatibility—many older units lack proper voltage regulation for LiFePO4 chemistry.

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