Dear Mike,
I read this on the RV forum I am a member of:
“I talked to support at Progressive Industries. His suggestion is to use the 50A outlet whenever possible. The thinking is that often the pedestals are corroded which causes high resistance and heat if drawing high loads. The 50A outlet has heavier wire, bigger contact area on blades, so in theory less heat. It’s worth a try – use the 50A outlet with your own adapter.”
I wondered what your thoughts are on this, Mike. The main topic was about a member’s 30A plugin on his cord melting due to a loose connection at the pedestal. —Karin S.
Dear Karin,
That’s actually a reasonable idea which I’ve discussed at a few of my seminars. If the 30-amp outlet on the pedestal is beat up, then far better to use a 50-amp to 30-amp dogbone adapter that matches your RV’s TT-30 cordset. It should be safe from overload since there’s a 30-amp master circuit breaker in your RV’s circuit panel.
While this is technically a code violation (sort-of/kind-of), I don’t think any electrical inspector would bat an eye at it. Just be sure to keep your own cordset and RV twist-lock connector (if you have one) clean and free of oxidation. I really like DeoxIT D5 from Caig Laboratories for this cleaning procedure to remove any oxidation, followed up with a spritz of silicon lubricant.Â
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 40 years in the industry. Visit NoShockZone.org for more electrical safety tips. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.
##RVT865
“While this is technically a code violation (sort-of/kind-of)” sort of kind of, like a woman being “kind of pregent’? it is flat out a code violation. and you are stepping on Dr. OHM’s and his laws. the only safe way to do this is to add a water proof (nema IP 65/66/67). you build a 30amp breaker box about 200.00 total and then you plug in your 30 amp cord to a 30amp plug. you have a 50 amp plug as your feed to this new breaker box, when you leave you take it with you.
How do you get electrical power cords to separate easily? When I have to use an adapter it can be extremely hard to pull them apart. I know I don’t want them loose, but, at least be able to separate them without many expletives.
Thank you.
While you never want to use any petroleum based product such a WD-40 spray lube, silicon spray is safe since it won’t cause the rubber or plastic insulation to break down, and it will help protect the brass contacts from corrosion. CRC Silicon Spray works quite well for this and it’s only about $6 a can in any automotive supply store.
I recently lost my 30 amp plug to a pedestal, probably to arcing (black wire blade was discolored & rubber was melted around that blade & corresponding set of jaws on socket likewise had melting). Pedestal breaker never tripped & no error readings on Progressive hard-wired surge protector. No evidence of preexisting damage to socket, tested pedestal before plugging in, & switched breaker off both before & after testing/plugging in. Posted problem on interactive site & the dogbone suggestion was one response, along with some other derisive comments that it is just what happens when RV’ing. Another was keeping cord contacts clean. Looking at MG Electronics Contact Cleaner for latter. I plug in when home to keep batteries charged & occasional spare bedroom use. Currently using 30 amp 25 foot extension cord (trailer is 30 amps). Three Questions: Can I damage the pedestal by using the dogbone? Should I be using a 50 amp extension cord when I plug in at home? Can I spray contact cleaner into pedestal socket? Thanks!
I always use a 50 amp when available. Most of the time the 30 amp outlet is burning up. You are absolutely correct about campground owners never getting around to fixing outlets. And if a short would occur the breaker would trip in a heart beat. Something not to sorry about
Mike – Regarding your recommended use of DeOxit (just ordered some) – are you saying to spray the DeOxit into the receptacle, or on the blades of the plug?
Both, actually….
If you are going to spray it into the receptacle, make sure that the breaker is off.
That’s a good suggestion. While contact cleaners are generally non-flammable, there are a few of them that use flammable propellants (such as butane) that could possibly catch fire. While the chance of an ignition source is quite low, it’s best not to take unnecessary chances.
Mike I respect most everything you say but my recommendation is don’t tempt fate. I agree with what you’re saying about people using undersized extension cords on wall sockets that are fed with 15 and 20 amp breakers and that’s what causes fires. That being said it doesn’t make it right.
The most important thing here is understand what your load is and make sure you are not overloading the wires no matter what size of breaker is on the other end. The breaker is not a gate keeper, it’s a safety device that is to protect you if you have an overload or a short.
You should respect everything Mike has to say, whether you agree with him or not! He knows his stuff! 🙂
he is telling people its ok to plug a 10awg cord in to a 50amp plug (adaptor) that is stupid, 50 maps need 6 or 8awg wire. this is code, not some made up thing. “While this is technically a code violation (sort-of/kind-of) ” his words. you need to add a breaker box at the pole where you plug in you plug into the 50amp side and go thru a 30amp breaker so 8awg to the breaker box then you 10awg (30 amp) cord to your camper.
Since there should be a downstream 30-amp circuit breaker in the RV’s load center, that’s what acts as the current limiter on that 10 gauge conductor. I’ve discussed this issue with several major manufacturers who build these type of adapters and that’s always their answer. But I really don’t like it even though it’s accepted by the RV industry.
American power has a lot of similar wiring conundrums. Consider that according to code you can plug a 16-gauge extension cord rated for 10 amperes into a NEMA 5-15 receptacle powered by a 20 amp circuit breaker.
I would never use a 50 amp breaker to feed a 30 amp 30 system. Because the 30 main in your RV only protects you from the inside breaker out of the breaker box. It does NOT protect all of your lead in wires from the pedestal into the RV through the walls and underbelly as the feeder wires travel to the inside breaker panel in the RV.
If you have a loose wire or a short you could start a fire before the 50 amp breaker you are feeding your 30 amp feeder wires with ever trip.
NEVER use a breaker at a higher rating than the wire it feeds.
Larry, a loose wire won’t cause too much current to flow, but a loose connector in a campground pedestal outlet can easily overheat. As I noted this 50-to-30 amp adapter is actually a code violation, albeit not a serious one as long as it’s a single point-to-point run. If you think about it, every time you plug a 16-gauge extension cord into a standard 20-amp Edison outlet in your home, you’re doing exactly the same thing. That’s why it’s way too easy to set an extension cord on fire in the U.S. with a portable space heater. There’s nothing to stop a user from plugging in a too small extension cord. And table lamps generally have 18-gauge cords plugged into 20-amp outlets. In the UK, each male plug has an internal fuse rated for the amperage of the power cord it’s connected to.
I think that a 50-to-30 amp dogbone is the lesser of two evils, and I’ve thought about this a lot…. The real problem is there’s no testing or maintenance protocol for campgrounds, and I’ve never seen any inspection beyond the power company meter. We can discuss this on the phone sometime, but getting campgrounds to replace their worn and burned outlets is a hard sell. I’m willing to entertain ideas….
Mike. you need to add your own breaker box at the drop, 50amp plug to new breaker box, to a 30amp breaker thru serg protector, then to a 30amp plug then off to your camper, this is the safest way. other then having some stand there 24/7. the box and parts is about 150 to 200, that’s a water proof box too.
Your circuit panel in your home uses a 200A breaker to feed a 15A breaker, so there is not a lot of difference. Even if the 15A breaker has a loose connection to the buss, you still can only draw 15A through the 15A-rated wire.
I have a 50amp coach and a 50 amp surge protector. Most of the time the protector stays in the coach attached to the 50 cord, then a dogbone to 30amp cord which is plugged in the pedestal.
Is my protector doing it’s job with this connection?
Interesting thoughts. If the 50A does have thicker wires feeding it, would it be smart to do this most of the time? I have a Class C with a 30 Amp system.
There’s just one pair of wires going to each pedestal, and if the pedestal has a 50-amp outlet, then the 30-amp outlet is connected to these same 50-amp wires through a 30-amp circuit breaker. So there’s really no advantage of a lower voltage drop due to heavier wires. So good thought, but no real advantage from that standpoint.