Shore power is electricity from a land-based source that runs a boat or RV while it is docked or parked. A shore power cord carries that power from the pedestal at the marina or campground to the vessel or vehicle, so the generator and engines can shut off.

Shore power supplies electricity to an RV parked at a campground or a boat docked at a marina. In both cases, a power cord connects the RV or boat to an electrical pedestal, allowing onboard appliances and equipment to run without a generator. RVs typically use straight-blade plugs, while boats use locking connectors to keep the connection secure as the vessel moves.

Choose a shore power cord that matches the amperage of the pedestal receptacle and onboard inlet (typically 30A or 50A), uses the correct connectors, and is long enough to reach without excessive voltage drop.

How a shore power connection works

30A vs 50A vs 80A Shore Power Comparison

RV shore power typically comes in 30A and 50A configurations. A 30A hookup supplies up to 3,600 watts at 120V, while a 50A hookup supplies up to 12,000 watts through two 120V legs. Marine shore power also includes a 50A, 125V option rated for 6,000 watts.

RV shore power ratings

Marine shore power ratings

30A shore power runs one roof air conditioner and a few appliances at a time. Most travel trailers, pop-ups, smaller fifth wheels, and many smaller boats use it.

50A shore power runs two or three air conditioners plus an electric water heater and kitchen loads. Large fifth wheels, motorhomes, and larger boats use it. A 50A RV plug always has four prongs.

80A shore power is not a standard RV or recreational marine cord rating. RVs typically use 30A or 50A connections, while larger boats may use 100A systems. Equipment requiring 80A needs a cord assembly rated for the load, with connectors matching the power source and onboard inlet. Depending on the configuration, this may require a custom assembly.

100A shore power is used primarily on larger yachts with substantial electrical demands. These systems typically use heavy-duty marine pin-and-sleeve connectors and can deliver up to 24,000 watts at 120/240V.

RV shore power cords: 30A and 50A

An RV shore power cord has a male plug for the campground pedestal and either a hardwired end or a female connector for the RV inlet. Check which one your RV has before you shop for a replacement.

30 amp RV power cord

A 30 amp RV power cord uses a NEMA TT-30P plug with three prongs: a flat hot, a flat neutral, and a round ground. It is the standard 30 amp power cord for travel trailers, camper trailers, and most smaller RVs. The cord inside is typically 10 AWG copper with three conductors, such as 10/3 SOOW.

Some RVs use a 30A twist-lock inlet instead of a hardwired cord. For those, a detachable cord with a TT-30P plug on one end and a twist-lock connector on the other works as the 30 amp RV power cord replacement.

50 amp RV power cord

A 50 amp RV cord uses a NEMA 14-50P plug with four prongs: two hots, a neutral, and a ground. The conductors are typically 6 AWG for the hots and neutral and 8 AWG for the ground. NNC carries 50A RV extension cords in 15 to 50 ft lengths, and 50A twist-lock RV replacement cords.

Marine Shore Power Cords

Marine shore power cords use locking connectors to prevent accidental disconnection as boats move with waves, wakes, and tides. Unlike ordinary extension cords, they must also withstand moisture, salt air, and frequent outdoor exposure.

30 Amp Marine Shore Power Cord

A 30A marine shore power cord uses a NEMA L5-30P locking plug at the dock and a matching locking connector at the boat's inlet. It operates at 125V and typically contains three 10 AWG conductors: hot, neutral, and ground.

Nassau National Cable stocks 10/3 SOOW portable cord for applications requiring flexible, moisture-resistant cable. For marine shore power, the completed cord assembly must also have suitable locking, weather-resistant connectors and meet applicable marine electrical requirements.

50 Amp Marine Shore Power Cord

Marine 50A shore power connections come in two configurations:

• 50A, 125V (NEMA SS1-50): Three conductors supplying a single 125V circuit, typically found on boats with moderate electrical demands.

• 50A, 125/250V (NEMA SS2-50): Four conductors supplying two power legs, used on larger boats with greater electrical demands.

Marine 50A cordsets commonly use 6 AWG power conductors, with the final conductor sizes determined by the cord assembly's rating. The plug and connector must match the pedestal and boat inlet.

Larger yachts may use 100A marine shore power systems with heavy-duty pin-and-sleeve connectors.

Marine Cord Construction

When selecting a marine shore power cord, look for:

• Corrosion-resistant conductors and contacts: Tinned copper helps protect against corrosion, while marine-grade connectors are designed for wet, salty environments.

• Water- and oil-resistant jackets: Flexible cord types such as STOW and SOOW are available for outdoor use, but the complete assembly must be suitable for marine shore power.

• Secure, weather-resistant connections: Locking plugs, watertight connector housings, and suitable strain relief help protect connections from moisture and movement.

ABYC E-11 covers electrical safety requirements for recreational boats, including their shore power connections.

Ground-Fault Protection at Marinas

Under the 2023 NEC 555.35, marina shore power receptacles require individual ground-fault protection rated at no more than 30 mA. This protection disconnects power when excessive electrical leakage is detected, reducing the risk of electric shock in and around the water.

80A and Higher-Capacity Shore Power Cords

Although 80A is not a standard recreational RV or marine shore power cord rating, larger boats commonly use standardized 100A pin-and-sleeve connections. Specialized vehicles and temporary power installations may require other configurations or custom-length cable assemblies.

For these applications, the cable and connectors must be selected together based on voltage, amperage, conductor count, operating conditions, and length. Type W portable power cable is one option for heavy-duty industrial temporary power, although marine installations require cables and complete assemblies specifically suitable for that use.

Nassau National Cable supplies flexible power cables in custom lengths and offers pre-terminated assemblies for industrial applications. Contact our team with the required voltage, amperage, connector specifications, and cord length to discuss available options.

Shore power cord length and 120V voltage drop

The figures use conductor resistance from NEC Chapter 9, Table 8, and treat each 50A leg as a 120V circuit, which is the worst case. Real loads rarely sit at the full rating for long, so actual drop runs lower.

The rule of thumb for shore power cords:

• Keep 30A cords on 10 AWG to about 50 ft. Step up to 8 AWG to about 75 ft, and 6 AWG past that.

• Keep 50A cords on 6 AWG to about 75 ft. Step up to 4 AWG for longer runs.

• For runs past about 150 ft, install a pedestal or outlet closer to the RV instead of a longer cord. Fixed wiring costs less per foot and drops less voltage.

Shore power adapters for RVs and boats

A shore power adapter changes the plug, not the capacity. The smaller rating in the chain always sets the limit.

RV shore power adapters

• 30A RV cord to 50A pedestal: 30A at 120V, using one leg of the 50A receptacle.

• 50A RV cord to 30A pedestal: 30A at 120V, shared by both legs of the RV panel. Run one air conditioner at a time.

• 30A RV cord to 15A or 20A outlet: 15A or 20A at 120V. Enough for charging and lights, rarely for air conditioning.

Marine shore power adapters

• 30A to 50A, 125V: Lets a 30A boat use a 50A, 125V pedestal at 30A.

• Y-adapter, two 30A to one 50A 125/250V: Combines two 30A pedestal receptacles to feed a 50A, 125/250V boat. It only supplies 240V when the two receptacles sit on opposite legs.

• Reverse Y, one 50A to two 30A: Splits a 50A, 125/250V pedestal to feed a boat with two 30A inlets.

Turn the pedestal breaker off before you connect or disconnect any adapter. Do not stack adapters, and never run shore power through a household extension cord.

Cable types for a shore power cord

Shore power cords need to withstand frequent coiling, movement, and outdoor exposure. NEC Article 400 covers flexible cords used for portable power connections. Common cable types include:

• SOOW, such as 10/3 SOOW for 30A cords or 6/4 SOOW for 50A 125/250V cords: Heavy-duty 600V flexible cord with an oil- and water-resistant rubber jacket. Suitable for custom power assemblies when properly rated and terminated.

• SEOOW, such as 6/3 SEOOW for 50A 125V marine cords or long 30A cords: Similar to SOOW but uses a lighter thermoplastic elastomer (TPE) jacket that remains flexible in cold weather.

• STW / STOW: 600V thermoplastic flexible cords commonly used in factory-made RV shore power assemblies, such as this 50A RV cord on STW. STOW adds oil resistance.

• Type W, such as 4/4 Type W: Heavy-duty 2kV portable power cable for rugged industrial applications and certain high-amperage custom assemblies.

• UL 1426 boat cable, such as 10/3 UL 1426 for 30A boats: Designed for onboard marine wiring, such as connections between the shore power inlet and electrical panel, rather than the detachable shore power cord.

The completed shore power assembly must have suitable connectors, conductor ampacity, and environmental ratings. NEC 400.12 also prohibits using flexible cords as substitutes for permanent building wiring.

Shore power cord FAQ

These are real questions boat and RV owners sent to the Nassau National Cable team.

Can I make a 200 ft 30 amp camper cord from 6-6-6 aluminum SER?

No. SER is building wire for fixed installations, and it cracks when coiled. At 200 ft, even 6 AWG copper cord drops almost 5% at 30A. Run fixed wiring to a pedestal near the camper, then use a short 30 amp camper power cord.

What cord connects a generator to a 30A RV 120 feet away?

Use TT-30P and TT-30R ends on a heavier cord than standard. At 30A over 120 ft, 10 AWG drops about 7.4%, 8 AWG about 4.7%, and 6 AWG about 2.9%. 6/3 SEOOW keeps the drop under 3%.

Can I use UL 1426 marine cable for a boatyard shore power cord?

No. UL 1426 boat cable is for fixed wiring inside the boat. A shore power cord needs flexible, hard-usage cord such as SOOW or a listed shore power cord set.

Is Type W portable power cable OK for marine shore power?

Yes, for heavy-duty custom cords. Type W is a rugged 2kV cable built for wet, abusive service. Recreational boats usually use listed shore power cord sets, so check with the boat builder or surveyor first.

What cable works on a self-retracting shore power cord reel?

An extra-flexible portable cord with fine stranding, rated for repeated reeling. A 50A, 125/250V service needs a 6 AWG, 4-conductor cord. Tinned copper adds years in salt air.

Why does a 50A RV plug need four wires?

A 50A RV service is 120/240V: two hots, a neutral, and a ground. A 50A welder outlet has only three wires and no neutral, so it cannot feed an RV until a neutral is added and the receptacle is changed to a NEMA 14-50R.

Is 6/4 SOOW good for a 50 amp RV cord?

Yes. 6/4 SOOW carries two hots, a neutral, and a ground for a 14-50P plug. A 60 ft cord drops about 2.5% at a full 50A per leg.

Are RV pedestal outlets GFCI protected?

NEC 551.71 requires GFCI protection on the 125V, 15A and 20A receptacles at RV sites. Requirements for the 30A and 50A receptacles depend on the code edition your state adopted, and many newer pedestals include it.

Can I get an 80 amp twist-lock shore power cord?

Yes, as a custom assembly. No standard 80A RV plug exists, so the cord is built to match the connectors on the site and the vehicle.

Get the right shore power cord

The right shore power cord comes down to the amp rating at the pedestal, the plug style on each end, and the length you need. Match all three, size up for long runs, and keep the contacts clean.

Nassau National Cable stocks 30A twist-lock cords, 50A RV cords, and portable cord such as 10/3 SOOW and 6/4 SOOW by the foot, shipped from four U.S. warehouses. For 80A and other custom shore power cables, send us the connectors and length, and our team will build the assembly for you.