Automatic Transfer relay box Burnt

[blackoctaupus]

Originally Posted by pconroy

And I'm not trying to be difficult, just trying to understand. Agreed that the bounce and flex of the motorhome will contribute to this problem. But we don't see (or don't hear about) the connections to the outlets having this problem. Granted they tend to see much less amperage and for much shorter times.


The wire inside the ATS was solid copper in mine. 10g too.



The ATS manufacturer has apparently switched to Wago connectors for the newer models. Whether that's driven by cost or something else, I don't know.


What's apparent to me is that annual rechecking of those connections is really important!

I don’t know if I got the Wago connection but the new box of the same model had similar connecter, which make me feel better because seem to be a better connection

[JimD]

Originally Posted by Vicr

Again, another electrical thread with some "misinformation". From an electrician (me): The electrical connection on the terminal strip specifically the middle 'hot" connection was not tight which caused an arcing event when under load. The arcing event caused excessive heat which in turn caused the insulation on the conductor and the terminal strip to degrade. The metal connections in the terminal strip also degraded to the point that the metal actually changed its metallic composition.

Why was the connection loose? Maybe not tight from the initial installation, maybe loosened up from the constant movement of the coach when traveling, who knows. Stranded wires do have a tendency to compress or 'relax naturally over time because of changes in temperature (expanding and contracting) and need to be checked and retorqued periodically.

Thank you for chiming in. I wanted to say something but decided to just let it slide.

Yes heavy current flow through wiring will warm it up causing it to expand a bit and shrink when cooled. Not a massive amount just a tad. Constant heat/cool cycles "may" result in connections loosening then again maybe not.

This had to be a case of loosened connections that kept heating up more and more over time. The designer would have picked a terminal strip that was capable of handling the max current expected. Any current higher than max should trip a breaker somewhere.

Just my opinion as an electronic technician.

[Weatherman1]

I had this happen when we were in bed and reading I smelled smoke and electrical insulation burning while we were in AZ and running the house air.
I checked running amps and found it was ok even with A/C and water heater in electric
mode running about 26 amps.
I suspect it was loose connections because my EMS did not trip and the voltage was fine.
I spliced it with some heavy duty wire nuts and bought a replacement junction terminal block. Relay was fine

[thenne1713]

Suspicion would be that the worst overheated screw was loose and arcing/ sparking; checking ALL wires/ breakers/ fuses/ lugs ANNUALLY is always smart. Loose= heat= more loose= spark/ arc.

[Johnynorthland]

Originally Posted by blackoctaupus

What will have cause this to happen, if this happen to you what was the diagnostic. We are camping right now and this happen to us. The RV shop will order a new relay box, will be here on Monday. But don't know when they will come to fix it.

thank you

MAKE SURE YOU GET THE UPDATED PROGRESSIVE DYNAMICS NEW TRANSFER SWITCH PART/NUMBER. it has Wago connectors, they won’t get loose like yours and mine did! Your photo looks exactly like mine. I have a 2019 Redhawk 25R

[thenne1713]

Originally Posted by pconroy

... But we don't see (or don't hear about) the connections to the outlets having this problem. .... !

Yup, ya do if paying attention to the fires, because someone pluggged in a space heater and didn't check for hot cord/ hot receptacle/ loose plug tension.

[blackoctaupus]

Originally Posted by Johnynorthland

MAKE SURE YOU GET THE UPDATED PROGRESSIVE DYNAMICS NEW TRANSFER SWITCH PART/NUMBER. it has Wago connectors, they won’t get loose like yours and mine did! Your photo looks exactly like mine. I have a 2019 Redhawk 25R

This is what they install, now I feel better about my system thank you for the picture

[blackoctaupus]

Did you had any trouble after that
thank you

[Johnynorthland]

Originally Posted by blackoctaupus

This is what they install, now I feel better about my system thank you for the picture

Make sure you frequently check all your plug ends. As they get oxidation, and not a bright shiny brass color anymore, you need to sand them a little with 220 sandpaper and use electrical contact spray on them and inside the female ends. And I always check the parks outlet, if it’s dirty looking, I spray that too. Just make sure nothing is energized when you spray.

[DAT-IT]

Hi,

Reading through this thread, I understand the explanations given, however I'd like to know if the OP was using the generator at the time of the melt down.

I guess my real question is whether power is always going through the transfer box? I was under the impression that it was to facilitate switching over to generator power, but was otherwise unused until then.

Could someone please clarify the power flows under generator and non-generator situations?

Thanks, Dave

Bonus points if you can tell me how my integrated solar panel fits in the equation.

[JimD]

Transfer switch is two inputs and one output. The relay will pass through shore power using most of the same internal components. When the generator powers on the relay will simply switch the set of contacts that are connected to the output.

Most likely the generator wiring will be connected to part of the terminal block while the shore power is connected to a different section of the block.

Looseness in any of the terminal connections can cause the melting problem. The more current being drawn from either shore or generator power increases the heating potential.

No bonus points here. The solar doesn't have anything to do with the transfer switch. It simply connects to the battery(s).

[DAT-IT]

Originally Posted by JimD

Transfer switch is two inputs and one output. The relay will pass through shore power using most of the same internal components. When the generator powers on the relay will simply switch the set of contacts that are connected to the output.

Most likely the generator wiring will be connected to part of the terminal block while the shore power is connected to a different section of the block.

You know, in retrospect, that makes perfect sense. I guess I was just assuming that the shore power went directly into the PDU and the generator/transfer box was just another input into it. But it's more sensible that all AC power goes to the transfer box with a single output. It makes the PDU design much simpler if it only has to worry about one input.

Thanks for pointing out what should have been obvious to me. :-)

Dave