What Gauge Extension Cord for a 30 Amp RV?
Standard 30A RV shore power (a TT-30 receptacle) needs a minimum of 8 AWG at 25–50ft, stepping up to 6 AWG at 100–150ft, per our Appliance Amp Draw → Gauge table — an ordinary household extension cord, even a thick 12 AWG one, is undersized for a full 30A service.
30A shore power is a fixed, heavy draw
RV shore-power rows in our dataset use the fixed NEMA receptacle amperage (30A on TT-30), not an estimate — so unlike a tool that draws its nameplate amps intermittently, the cord has to be sized for the full service rating. Per the Cord Gauge Ampacity Index, even 10 AWG only carries ~25A through 50ft and falls to ~18A by 100ft, which is why the RV row starts at 8 AWG and steps to 6 AWG on long runs.
The floor, by run length (30A / TT-30 service)
| Run length | Minimum gauge |
|---|---|
| 25 ft | 8 AWG |
| 50 ft | 8 AWG |
| 100 ft | 6 AWG |
| 150 ft | 6 AWG |
Minimums from our Appliance Amp Draw → Gauge dataset (v1.0). We round toward the safer gauge wherever sources disagree.
When you shop, search for the connector plus the gauge together — an 8 AWG 30A TT-30 RV extension cord — and confirm the plug family in the listing photos before buying.
Match the connector before the gauge
TT-30 (RV), L5-30, and L14-30 (generator twist-locks) are different, non-interchangeable plug families — the wrong one will not fit or lock in. If you are feeding the RV from a portable generator rather than a pedestal, see our generator cord gauge guide and match your generator's actual output receptacle.
This page is general reference, not an electrical code determination. Local code governs.
Frequently Asked Questions
For standard 30A RV shore power (a TT-30 receptacle), our Appliance Amp Draw to Gauge table calls for a minimum of 8 AWG at 25ft and 50ft, stepping up to 6 AWG at 100ft and 150ft. An ordinary household extension cord — even a thick-looking 12 AWG one — is undersized for a full 30A RV service.
Not necessarily — the connector is a separate spec from the gauge. RV shore power uses the TT-30 receptacle, while portable generators commonly use L5-30 or L14-30 twist-locks, and those plug families are not interchangeable. Match the exact receptacle shape on your RV or pedestal first, then check the gauge for your run length.
Because voltage drop accumulates with length. The 30A draw never changes, but the cord's resistance over 100-150ft does, and keeping the drop within the commonly-cited 3% limit on a 120V circuit at 30A requires stepping up to 6 AWG. This is the same length-driven math documented across our Cord Gauge Ampacity Index.
The combined chain obeys the same voltage-drop math as one cord of the total length, and is only as capable as its thinnest section — so two 50ft cords need the gauge our table lists for 100ft (6 AWG), not 50ft. One cord of the right length and gauge is the better buy.