RV Transfer Switch - Problem and “Fix”
While camping at Pinnacles National Park, we had some MAJOR electrical issues. In the video below (starting around minute 12), we describe our trouble-shooting process and how we “fixed” the issue with our RV’s transfer switch.
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Our Electrical Set-Up at Pinnacles National Park
We own a 2022 Entegra Accolade XL 37L — otherwise known as “Big Lady.” This rig is basically the same as the Jayco Seneca Prestige. Both are 50-amp “Super C” RVs equipped with an on-board Onan generator.
Camping at Pinnacles National Park
The campground at Pinnacles National Park contains only 30-amp pedestals. As such, when camping in places like Pinnacles, our set-up involves (1) a 30-to-50 amp dogbone and (2) a Hughes Power Watchdog EPO 50-amp “smart” surge protector. “EPO” is an acronym for “emergency power off.” If something is wrong with the electrical power at the pedestal, the “smart” surge protector is supposed to provide an error code and cut power. Other brands (like Progressive Industries) sometimes call this device an “electrical management system” or EMS.
Our Electrical Issues at Pinnacles National Park
After a couple of days of camping at Pinnacles National Park, we simply lost power. The first time, the power outage was cause by a blown breaker at the campground breaker box. Easy fix. The second time, we could not figure out what was going on.
Our EPO/EMS told us that the power at the campground pedestal was fine (i.e., no error codes). A Pinnacles staff member also checked the pedestal and told us it was okay. However, every time we tried to power up the RV from the pedestal, the power would not come on. We even tried hooking up to a DIFFERENT pedestal at Pinnacles and still got the same result — no power! In the video, we explain some of our other trouble-shooting steps in more detail.
In the end, we determined that our Southwire Transfer Switch was stopping the power from the Pinnacles electrical pedestal from coming into the RV. The transfer switch was detecting an “open ground” even though our EPO/EMS did not detect any problems.
We contacted Southwire, and they sent us the following information to test.
Table 1: Southwire’s definition of “good power.”
FIG 1: Southwire’s diagram and photo showing how to measure voltages.
The voltage readings we were getting with our multimeter were as follows:
Pinnacles Campground Pedestal:
L1 to N: 120 V
L1 to G: 121 V
N TO G: 2.2 V
Automatic Transfer Switch:
L1 to N: 120 V
L1 to G: 119 V
L2 to N: 120 V
L2 to G: 119 V
N to G: 2.0 V*
L1 to L2: 120 V**
*That N to G voltage reading should be zero (not around 2 V). Was that our problem?
**The dogbone adaptor connects the single 120 volt hot pole to both the L1 and L2 inputs of the RV’s 50 amp breaker panel. In hindsight, I’m not sure why we were reading 120 V instead of 0 V on the L1 to L2. Perhaps we took an improper reading.
Regardless of what was causing the electrical problem, the BIGGER problem was that we were camping at Pinnacles over a VERY HOT Memorial Day weekend. We needed to run our air conditioners, especially so our dogs could stay cool. Somehow, we needed to get power to the rig.
What about just using the generator? Our RV powered up perfectly fine with our generator. Unfortunately, generators are not permitted at Pinnacles National Park under any circumstances. Even if we cleared running the generator with our neighbors, the park staff said “no generators!” That’s when we started researching more about transfer switches and whether there was some work-around to our electrical dilemma.
No generators are permitted at Pinnacles National Park
What is an RV Transfer Switch?
As part of our trouble-shooting process, we learned a lot about transfer switches. Our transfer switch is manufactured by Southwire, but there are several others on the market. As with most brands, there are “dumb” transfer switches and “smart” ones. The “dumb” ones just make sure the appropriate power source is being used, giving priority to the generator. The “smarter” transfer switches, like ours, do a little more.
Wiring diagram for our Southwire Transfer Switch (Model 40101)
Interior of our Southwire Transfer Switch (Model 40101) — which is located underneath our bed.
Model 40100 (“dumb”)
Transfers to generator power automatically when energized after a delay
Does NOT provide surge protection
Model 40101 (ours - “smart”)
Reverse polarity
Open ground
Does NOT provide surge protection
Model 41261 (what we ordered - “smarter”)
Reverse polarity
Open ground
Surge protection
Model 40350 (“smartest”?)
Reverse polarity
Open ground
Surge protection
Low (132V) voltage
Miswired pedestal
High / low frequency
Interestingly, many Entegra Accolades and Jayco Senecas were manufactured with “dumb” transfer switches. We don’t know when or why Jayco/Entegra made the switch (pun intended).
How We Fixed our Transfer Switch Problem?
Since we could not use our generator, our temporary “fix” to our transfer switch problem was to bypass the transfer switch entirely. In short, Kasie re-routed the wires from the RV’s electrical cord directly into the 50-amp breaker. It’s not as easy as it sounds because working with those large wires in such a small space is not easy (see the video for more details). Importantly, we continued to use our EPO/EMS to detect electrical/power issues when we turned on the power, hoping that the EPO/EMS would detect any major electrical issues.
Did bypassing the transfer switch work? YES YES YES!
By bypassing the transfer switch under these circumstances, we were able to get power directly from the pedistal and keep our air conditioners running for the rest of our stay at Pinnacles National Park. Woo hoo!
Was the Electrical Problem the Campground Pedestal or the Transfer Switch?
To recap…
Our transfer switch was detecting an open ground at the Pinnacles National Park campground, even though our EPO/EMS was telling us that everything was fine at the pedestal. The transfer switch therefore cut off power. Was the transfer switch sensor bad? Or was the pedestal power really faulty? Why would the power be bad at two different pedestals? Was the EPO/EMS doing its job properly? Clearly, the transfer switch was picking up some electrical issue that the EPO/EMS did not, but why? Just different cut-offs/sentitivities to the “open ground”? What exactly is the N to G sensitivity on the transfer switch? On the EPO/EMS? We contacted both companies, and neither Southwire nor Hughes could give us definitive answers. If you have some insight about what was going on, please let us know.
We do know that when we got to our next campground, Kasie reconfigured the transfer switch to its original condition (i.e., reversed the bypass configuration). This time, the transfer switch worked perfectly fine and we were able to use shore power without any issues. The bottom line is that we think there was something wrong with the power supply at Pinnacles National Park. We’ve had no problems with our transfer switch (knock-on-wood) since our stay in Pinnacles National Park.
Should We Get a “Dumb” Transfer Switch?
Because we didn’t know whether or not our transfer switch was faulty/bad until we got to the next campground, we ordered a replacement to be shipped there. The replacement was a “smart” transfer switch that is also supposed to detect an “open ground” (Southwire Model 41261). We ended up returning that “smart” transfer switch. If we would have replaced the transfer switch with another “smart” one, we would have had the same issue at Pinnacles National Park.
All of this begs the question as to whether a “dumb” transfer switch might be the better way to go in the future. Does the EPO/EMS have enough smarts to tell us if there are major electrical issues with the pedestal? Or is the redundancy of a “smart” transfer switch good for some reason?
Channelling my inner Carrie Bradshaw, I kept asking myself: “When it comes to transfer switches, is “dumber” better?”
I would love to know what you think….
