Hi Phil, The reason for the 4th pin in a NEMA 14-50 is because an RV has plenty 120V applicances, so to avoid the use of current going over the Earth wire as is necessary in a 10-30 (Dryer plug) the Neutral is connected on its own prong, so you are essentially extending the 3-wire plus ground service from your home into your RV.
On Wed, Feb 11, 2026 at 2:53 AM DOOLEY PHILIP G JR via EV <[email protected]> wrote: > > We have been using a NEMA10-50 outlet indoors in our garage with good > success for the last 25 years. We have 4 welders as well as the EVSE and > backup generator that share the single outlet. The heavy prongs have never > gotten hot and the cost is low. None of our 240V loads need a neutral > connection, so there is no problem using the middle prong as earth. This > outlet used to be the standard for all 240V applications, but UL or NEC > decided that the small neutral current of a stove or dryer needed its own > pin. Yes, our stove and dryer have 4 pin outlets to current standards. Only > one of our 3 EVs can use an EVSE, if we get another one, some re-wireing will > be required. The original 4 pin plug on our Siemens EVSE did melt, but the > wires in its cord were too small and the outlet was old. > Phil > > On Tuesday, February 10, 2026 at 12:51:45 PM EST, (-Phil-) via EV > <[email protected]> wrote: > > Personally I always advise people get a permanently installed EVSE now. > This is something they will use every day. Many new EV owners are always > tempted to try to "cheap out" and use a portable EVSE for daily use. I've > seen that the UMC portable EVSE that Tesla supplies is not nearly robust > enough. Best to keep that for emergencies and get one installed. A new > EV is a significant investment, so spending a couple thousand more for home > refueling is justified. > > I do not like recommending a 14-50 (or other outlet) connected unit, there > have been too many melted outlets and fires, yes it CAN work, but it also > adds another point of failure. In the rare event of an EVSE failure the > extra burden of having to get a new one installed is not that bad, this is > when you can either break out your "emergency" EVSE or just use DCFC for a > few days. It's really rare. > > On Tue, Feb 10, 2026 at 8:58 AM Lee Hart via EV <[email protected]> wrote: > > > Jay Summet wrote > > > Assuming you don't plug/unplug the plug frequently, the connection on a > > NEMA 14-50 should be just as good > > > as hard wired (but if you exercise it frequently, it may eventually get > > lose, leading to resistance and heat). > > > > I agree. I've used 14-50s for decades for my EV chargers (and welder and > > heater). The chargers stayed plugged in 90% of the time. I only unplugged > > it when I needed to use the welder or heater. In 40+ years I never had to > > replace one because it wore out. > > > > Note: You can get receptacles that mount in a recess, so you can't get > > your fingers on the pins when partially engaged. > > -- > > Excellence does not require perfection. -- Henry James > > But it *does* require attention to detail! -- Lee Hart > > -- > > Lee A. Hart https://www.sunrise-ev.com > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260210/085fc2ab/attachment.htm> > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20260211/b58ec625/attachment.htm> > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
