Loose Screws!
Don’t forget to check your generator transfer switch screws for proper torque
Great article Mike
I am an administrator for the Winnebago Tour/Ellipse Facebook group and find that the ATS is a common source of trouble. Most people never check the torque on the contactor screws and because the attachment is screw to bare multi stranded copper wire, over time the screw tension on the copper wire becomes less as the copper wire is soft and mailable. I wish that the attachment method was different such as soldered or crimped lugs. Would this be more reliable - Tom Prevost
Hey Tom,
Thanks very much for the kind words. A few points on wire termination methods. You are correct that wiring on the contactor/relays of transfer switches do tend to get loose in RVs. But a lot of that loosening seems to be due to road vibration as well as normal heating/cooling cycles.
Don’t tin your wires
As far a tinning the wires with solder prior to termination, that’s not a great idea since solder is even more malleable than copper. And as you noted, copper does tend to deform under pressure. We found this to be a big problem in pro-audio gear that traveled a lot between concerts. Any connectors with tinned wires had to be retorqued once a year due to road vibration. And we found that fine stranded wire needed ferules to survive at all.
Maybe a better solution
A better solution could be forked spade connectors, but they have to be properly soldered or crimped with the right tool to make a lasting connection. And not all of them are rated for solid wire. I don’t see a lot of them in RVs.
Wago to the rescue?
I’ve seen that a number of RV load center manufactures are going to WAGO connectors for wiring termination. Since they’re self tightening that’s probably the best solution. But I’ve never seen any of them on transfer switches.
For now, it’s best to retorque the terminating screws in your RV load center and transfer switch every few years, or even yearly if you’re doing a lot of driving. I drove my Sprinter van 40,000 miles per year, and things were always loosening up.
Watch this video below on how to use a torque limiting screwdriver on a transfer switch.
Let’s play safe out there - Mike
Mike - in the marine world, soldered connections are an area of concern, as soldering makes the wire strands brittle and subject to cracking. The American Boat and Yacht Council (ABYC) standard E11.15.3.8 states that solder not be the sole means of mechanical connection.
ABYC notes that when a stranded conductor is soldered, the soldered portion of the conductor becomes a solid strand conductor, and flexing can cause the conductor to break at the end of the solder joint unless adequate additional support is provided.
In effect, if you solder your connections, the wire also needs to be supported to prevent flexing.
RV's are subject to the same vibration and mechanical stresses as boats. ABYC standards are worth considering when working on RV's, especially as RV's have no equivalent standards.