Tuesday, December 7, 2021

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RVelectricity™: Important 30-amp outlet voltage reminder

Dear Readers,
It seems like the number of emails I get about licensed electricians accidentally wiring 30-amp RV outlets for 2-pole 240 volts instead of 1-pole 120 volts is rapidly accelerating. Some of this is probably due to a huge influx of new RV buyers in the last year. And some is likely because RV owners want to use their RV trailer at home for an “outside” office or visitor’s bedroom.

In any event, installing a dedicated 30- or 50-amp pedestal outlet on your house is a great idea. Just make sure your electrician wires it correctly. Read this email…

Fanmail from some Flounder (Thanks, Bullwinkle)

Hey Mike,
Still no RV inlet installed here, but you’ll be delighted (sarc) to know that I just had a 10-minute debate with another experienced electrician that insisted that my trailer had to be wired for 220 and required a dual pole breaker.

That’s TWO Licensed Electricians – with at least 20 years’ experience each – that both insisted on the same wrong thing. If I didn’t know better, I’d have gone along with it!

When I showed them the 30AMP receptacle and asked them to look very closely at the markings, their eyes nearly popped out of their heads. “It looks like a dryer receptacle, doesn’t it? But it is slightly different! Check out the markings!”

Anyway, you saved my butt TWICE. Thank you! —Mark in Massachusetts

Here’s why this happens

This is a common mistake made by residential electricians because the TT-30 receptacle closely resembles an old-school 230-volt dryer outlet that was common in the 1960s. So, a casual look at the RV outlet they’re about to install may make them believe it needs 240 volts, when it’s actually wired for 120 volts.

If you allow them to wire it to 240 volts and plug your 120-volt RV into it without an EMS Surge Protector to monitor the voltage, it can do thousands of dollars in damage in just a few seconds.

Now Hear This!

Please make your electrician read my article on Pedestal Power Principles before they begin any RV pedestal outlet installation at your house. Getting repair parts for a burned up electrical system in your RV is getting nearly impossible.

Read Power Principles HERE.

Let’s play safe out there….

Mike Sokol is an electrical and professional sound expert with 50+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

For information on how to support RVelectricity and No~Shock~Zone articles, seminars and videos, please click the I Like Mike Campaign.

##RVT1024

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Drew
1 month ago

A question for Mike: Why would any licensed electrician think that the ground on a TT 30 plug is for neutral?

Mike Sokol
1 month ago
Reply to  Drew

I’ve had hundreds of emails about this mistake over the last 10 years. While a residential electrician may have installed dozens or even hundreds of dryer outlets in their career, your TT-30 RV receptacle installation may be his first.

howard cole
1 month ago

Regarding Sokol article – Seems that most people would know there is something seriously wrong when they see the shape difference in the 120 vs 240 male verses female receptacles and plug.

Mike Sokol
1 month ago
Reply to  howard cole

I just know that I get at least several emails about this mistake every month.

wanderer
1 month ago

Mike, great article, but, pros hate to be told what to do or given articles to read, and the Power Principles is geared toward the RVer.

Maybe think about writing a very brief Technical Note page, terse, professional language aimed directly at an electrician?

Mike Sokol
1 month ago
Reply to  wanderer

But that type of article doesn’t belong on RVtravel…

Kevin
1 month ago

I have a 240 30 amps welder plug which I’m trying to look for adapter to reduce to 120 so I can plug in my Rv. If no adapter or dogbone oh well.

Mike Sokol
1 month ago
Reply to  Kevin

No, that won’t work. You would have to completely rewire the circuit breaker and receptacle.

mike henrich
1 month ago

Over my 30+ years as an electrician, I’ve repaired quite a few mis-wired RV receps. Some of them were installed by electricians. And of course, I still get new RV owners that think the 120 volt 30 amp hookup needs to be 240 volts.

Mike Sokol
1 month ago
Reply to  mike henrich

Really looks like it should be 240 volts, doesn’t it…