Quick answer
A TT-30R is a straight-blade, grounded 30A 125V receptacle intended for recreational-vehicle service. A direct RV cord match requires a TT-30P plug at the RV cord. Verify generator continuous output, RV starting loads, neutral and grounding instructions, cord condition, and total demand before relying on the connection.
TT means travel trailer, not a generic 30 amp outlet
Leviton identifies TT-30R as a 30 amp, 125 volt, two-pole, three-wire grounding receptacle for recreational vehicles. The mating plug on a typical 30 amp RV cord is TT-30P. Read those markings instead of identifying the device only from angled blades or an online photograph.
A TT-30 connection uses one hot conductor, one neutral, and one equipment grounding conductor. It does not supply two opposing hot legs and does not create 240V. This distinction controls what adapters and downstream equipment can be considered.
TT-30 is not a dryer outlet and must never receive 240V
Older NEMA 10-30 dryer connections and TT-30 devices are not the same system. Similar amperage and a superficial resemblance do not establish compatibility. Applying 240V to an RV designed for a TT-30 125V source can damage equipment and create fire or shock hazards.
Before connecting at a generator, campground pedestal, adapter, or extension, confirm the full NEMA designation and measured or documented source voltage using procedures appropriate for the equipment. If a device is unmarked, damaged, altered, or wired inconsistently with its documentation, stop and obtain qualified inspection.
A TT-30 generator outlet is a direct interface, not a capacity promise
A generator with TT-30R can accept a matching TT-30P RV cord, but the usable continuous power is governed by the generator rating on the selected fuel, its breaker, ambient conditions, altitude, and any simultaneous load on other receptacles. The outlet label alone does not prove full 30 amp continuous output.
Build an RV load schedule that includes the converter or battery charger, refrigerator operating mode, water heater, microwave, receptacles, and air-conditioner running and starting demand. High-demand appliances may need to be sequenced rather than operated together.
Use adapters only when source and destination stay electrically compatible
An L5-30 generator source can sometimes serve a TT-30 RV through a listed L5-30P to TT-30R adapter because both systems are 125V three-wire configurations. The adapter still has to preserve grounding and carry the intended current, and the complete load remains limited by the generator.
A 5-20 source can provide limited shore power through a listed RV adapter, but it does not become a 30 amp source. A 14-50 source-to-TT-30 adapter must be a purpose-built product that delivers the correct 125V path. Never improvise conductor bridges or use an adapter whose internal connection and ratings are not documented.
Inspect the RV power path before every generator connection
Inspect the generator receptacle, plug blades, strain relief, flexible cord, surge or energy-management equipment, RV inlet, and visible wiring for heat damage, looseness, moisture, or missing grounding features. Keep connections dry and supported so the cord does not pull on the generator panel.
Operate a combustion generator outdoors in its approved location. Follow the generator startup sequence, normally with RV loads disconnected or switched off when the manual requires it. Add loads deliberately and investigate repeated breaker or GFCI trips rather than bypassing protection.
Frequently asked questions
Common questions
Is a TT-30 plug 120V or 240V?
TT-30 is rated 125V and is commonly called a 120V RV connection. It is not a 240V connector.
Can I plug a 30 amp RV directly into a generator?
Yes when the generator provides a correctly rated TT-30R, the RV cord is TT-30P, and the generator output, grounding instructions, cord, and RV load plan all agree.
Can a 20 amp generator outlet power a TT-30 RV?
A listed adapter can provide limited 125V shore power, but the system remains limited to the 20 amp source and generator capacity. Air conditioning and other large loads may not be available.
Is TT-30 the same as L5-30?
No. Both can be 30A 125V three-wire configurations, but TT-30 is straight-blade and intended for RV service, while L5-30 is a locking family. A listed adapter is required between them.
Primary references
CordFind summarizes connector specifications and public safety guidance. Always follow the instructions supplied with your equipment.