Charging Systemsarticle

RV Shore Power Setup: TT-30, 14-50 and Wiring

How shore power works in a van or RV build: NEMA TT-30 vs 14-50, converter-chargers and the NEC Article 551 requirements that apply.

By Jack KennedyUpdated October 29, 20263 min readPractical, transparent guidance

Building in the UK? Read the UK version →

Electrical hookup pedestal at an RV campsite
Unknown author Unknown author · Public domain · Resized
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Shore power is the fastest way to top up a van or RV battery — plug into a campground pedestal or household outlet and let a converter/charger do the work. Here's how the US connections and wiring work.

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TT-30 vs. 14-50: which do you need?

ConnectorAmpsVoltageTypical use
NEMA TT-3030A120V onlyMost van builds, smaller RVs, most campground pedestals
NEMA 14-5050A120/240V split-phaseLarger RVs/motorhomes with multiple AC units, large appliances

For the vast majority of van conversions — a single converter/charger, maybe an inverter/charger, lights and outlets — a 30A (TT-30) inlet is plenty. A 14-50 is overkill unless you're running genuinely RV-scale 120V loads.

Several NEMA household receptacles viewed from the front
US-style receptacles differ in configuration and rating. The exact circuit design determines which is appropriate. Photo: Yak99. Public domain. Resized for this page.
Exposed fine copper strands at the ends of two insulated wires
Stranded copper conductors make the cable construction visible. Select cable area and insulation for the actual circuit. Photo: Scott Ehardt. Public domain. Resized for this page.

The converter/charger

The shore power inlet feeds a converter/charger, which:

  • Converts 120V AC to regulated 12V DC
  • Charges the house battery with the correct (ideally LiFePO4) profile
  • Can power 12V loads directly while plugged in, reducing battery drain

US picks: Victron Blue Smart IP22 12/30 ($215) — Bluetooth-enabled, multi-stage, LiFePO4-compatible. PowerMax PM4-55A ($150) — budget option, widely used in towable RVs and conversions.

Comparison table: TT-30 against 14-50
The pedestal outlet drives the whole design

US equipment options

Compare a combined inverter/charger route

This is relevant only if you also need inverter power. It is not a complete inlet, cable, breaker-panel or shore-power installation kit.

120V inverter/charger

Victron MultiPlus-II 12/3000/120-50 120V (UL 458) Inverter Charger

One route for a build that needs both an inverter and shore-power battery charging.

Check before choosing: This exact 12V/120V model, continuous watts versus VA, battery-current limits and qualified AC installation.

These links open our US shop. Check the exact configuration, current price and availability there; affiliate products are purchased from the named supplier. We may earn a commission from qualifying purchases.

A NEMA TT-30 RV plug and matching receptacle
The distinctive TT-30 plug-and-receptacle pattern is used for a 120V RV supply; do not confuse its shape with a dryer outlet. Photo: PAR. Public domain. Resized for this page.

Plugging into a household outlet

A standard household outlet (NEMA 5-15, 15A, or 5-20, 20A) can power your van through a 30A-to-15A "dogbone" adapter. You won't get the full 30A — you're limited to whatever the household circuit can safely supply (typically 12-16A continuous on a 15A circuit) — but that's enough to run a converter/charger and basic loads.

Don't overload a household circuit

A 15A household circuit may also be feeding other things in the house. Drawing close to its limit from your RV converter plus whatever else is on that circuit can trip the breaker. For just charging the battery, this is rarely an issue — converters typically draw well under 15A.

A grounding conductor with a ring terminal ready for a chassis connection
A ring terminal and grounding conductor show the physical connection hardware; bonding requirements depend on the complete system. Photo: Nathanhall78. CC BY-SA 3.0. Resized for this page.
Two red insulated wires terminated with crimped ring lugs
Ring lugs on stranded wire. Match the conductor size, stud size and crimp tooling to the terminal. Photo: Hundehalter. CC BY-SA 3.0. Resized for this page.

The 120V side is NEC Article 551 territory

Everything from the shore inlet through the breaker panel to any 120V outlets must follow NEC Article 551 — including GFCI protection on outlets and proper grounding/bonding. The DC output of the converter/charger is DIY-friendly; the AC input side should be installed or inspected by a licensed electrician.

Never back-feed shore power from an inverter

If you also have an inverter, never wire it to feed back into the shore power inlet without a proper transfer switch (built into combo units like the Victron MultiPlus). Back-feeding can energize the shore cord and create a serious shock hazard for anyone who plugs you in.

Diagram: The shore path in a van or RV
Illustrative topology. NEC Article 551 requirements are covered in the article.
Step diagram: Matching every part to one service rating

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JK

Jack Kennedy

Jack Kennedy is a self-builder who has built two vans. He created Roam Wired to simplify conversion planning and share free tools, supported by affiliate links.

About Jack