50 Amp extension cord - ok?

[VSG]

NEMA 14-30 (240V/30A) is commonly used for electric clothes dryers. I've never personally seen that on an RV hookup pedestal, but I suppose it might be used somewhere...

The typical 30 amp outlet at RV parks is a TT-30, which is a three prong 120V/30A.

I think a 14-50 extension cable will be more useful than a J1772 cable, as it can be used for your trailer too, not just your car. You can always get small adapters to let you use the 14-50 cable with a variety of other outlets, in case you need to plug into someone's dryer outlet. Better to have too heavy a cable than too light

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[Bill P]

So, A. I'm using one right now and have done so for a number of years. And, B. I usually drop the amperage if it's a campsite/RV hookup. Often by 50% since we will be there for multiple days.

Commenting anyway on your prohibition comment, it's so weird. I've seen it as just general anti-EV sentiment which is often rooted in political leaning (EVs interfere with other RVs, EVs will spontaneously combust, we don't give you gas so why take our electrons.... Etc.).

But also, RV sites can often be 50-75 years old. And Jethro buried that 8 gauge Romex during the Carter years. Sure the breaker says 50 amps, but no one ever inspected it, and the main circuit sure as hell can't support all 36 sites at full 50amps. But with staggard use and lower wattage applications, it was never an issue. So basically you have a legitimate infrastructure problem as well.

Very good point about aging (and probably never inspected) infrastructure. And EV charging involves significant (approx 7.5kW) continuous load. Here's my proposal (for any RV park operators who may be listening): if you know your stuff is code compliant, just slap meters on a few sites and advertise them as "EV sites." If you question what's underground, run a few new (compliant) cables (with meters) and make them your EV sites.

There are a lot of people pulling travel trailers. And the number using EV's is admittedly small, but will probably grow. There are RV parks all over the place in fast charger deserts. Overnight level 2 charging is preferable to fast charging. And level 2 infrastructure costs a fraction of fast charging infrastructure. There's a business (that doesn't require much capital expense) which could benefit both sides sitting right there.

 

[Bill P]

I charge this way every day at home; in the summer.

Have a 14-50 plug in the garage on a 50A circuit. In the winter truck is in garage, I plug mobile charger into socket and charge overnight. In the summer, I put our boat in the garage, and the truck sits in the driveway. I secure a 30ft RV extension cord to the baseboard, plug it into the outlet and route it to the front of the garage where the mobile charger plugs in. Cord from charger to the truck routes under the garage door to the truck.

All components from the breaker thru the extension cord are rated at 50A, I only charge at 32A (max of mobile charger), so I'm well under the 80% rule. Thermal camera shows no more than 10deg bump over ambient on any component in the system.

Works for me, I recommend everyone do their own risk analysis before following the lead of anyone else; especially random people on the internet like me

Thanks for this!

 

[Bill P]

It'll be fine - I've done it many times. I recommend running at a lower current, though. If I recall correctly the Rivian portable charger won't go over 32A, which is fine - that's nearly a 40% derating for a 50A extension cord and outlet. I also suggest that you should feel the cord and the plugs (with your hand) for excessive heat, after it's been charging awhile.

Thank you! I agree with regular heat inspections.

 

[jb0063]

Hi All: I tried searching for this and couldn't find it - apologies if it's been covered.

I'm pulling a travel trailer in some off-the-beaten-track areas - ie no fast chargers, but plenty of RV parks with 50 amp service. Aside from parks that prohibit EV charging (a whole other discussion) there are many with back in spots where my portable charger cord is too short to reach.

I'm aware that no extension is preferable, shorter is better, and the largest guage is the best. But assuming you adhere to these principles, what are your thoughts on using a 50 amp extension cord from an RV supply place on occasion?

Any guidance from my wiser/more experienced compatriots is appreciated!

I used this with the home charger for a while with no issues. An important thing is to also check the receptacle that it's plugged into. If the plug is not tight, there can be arcing inside the outlet box, which can ignite a fire. https://www.amazon.com/dp/B09LYDWX1V

 

[JeepEVer]

My Tesla is parked on the opposite side of the garage from the 240-volt EV outlet. I have a 50-foot cable running along the back wall of the garage, and typically charge at 32 amps with the Tesla mobile charger. I have had no issues in the five years using this setup.

 

[Jonger1150]

Has anyone located a 50 foot 48 amp charger other than this?

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