Transfer Switch (IOTA-50R)

[wolfe10]

dlevendofsle,

Welcome to the FMCA Forum.

Most of these ATS overheats are caused by lose connections.  A very good idea to tighten all the connections annually.  A 3 minute job that can save a lot of problems.  Yes, with the shore power disconnected and generator off.  Also, depending on your coach's wiring, inverter off.

[manholt]

Also, if your generator is set to come on automatically at loss of power...turn that feature off also!  To early for fourth of July!!!

[fagnaml]

I know this is an old "string" of comments, but I wanted to share that this past Saturday afternoon, 5/19/18, I experienced the same overheating / small fire incident with my Iota ITS-50R transfer switch in my motorhome (see attached photos). 

This past Saturday evening my son and in-laws hosted a surprise 30th birthday celebration for his wife (who is a great daughter-in-law!) in Lake Charles, LA.   My wife and I took our motorhome to keep the party a surprise (staying with my son in his home would have ruined the surprise).  While getting ready for the party, all power inside the motorhome suddenly went out.   First I walked outside to see if the A+ RV Park near Sulphur, LA had experienced a power failure.  Hearing lots of RV A/Cs humming, I next checked the power pedestal to see if the 50 amp breaker had tripped (answer was no).  Next I checked 50 amp breaker inside the motorhome -- it was OK.  So next I opened the left rear compartment where the shore power cable is stored and was stunned to see the burned power selector box!!   My first thought was "what the **** did I screw up now ?!".   My second thought was to say a prayer of thanks to God and my guardian angel that "only" the selector switch caught fire!   

After safely returning home yesterday, my Goggling yesterday evening found a lot of information including safety recalls for the Iota transfer switch.  Thor Industries issued safety recalls for Iota switches used in their Keystone RVs which has me very disappointed, even angry, that Thor has not issued a safety recall for Iota transfer switches used in their Damon motorhomes!  Earlier this morning I submitted my incident to Thor Customer Service requesting that Thor pay all costs for a new switch.  I'll let the forum know how Thor responds.

All I can say is if fellow forum members still have an Iota ITS-50R power transfer switch to get it inspected / replaced "now".  Also, I had nothing stored in the compartment where the Iota switch resides except for two small rolls of coaxial cable and a 150 foot extension cord.   That would be a good practice for everyone -- don't store stuff in electrical equipment compartments!

Since this thread is years old, should I start a new post sharing my experience?

The smell of burned electrical wires and burned plastic will stay with me for a long time....

[kaypsmith]

On ‎2‎/‎5‎/‎2018 at 10:58 AM, wolfe10 said:

Most of these ATS overheats are caused by lose connections.  A very good idea to tighten all the connections annually.  A 3 minute job that can save a lot of problems.  Yes, with the shore power disconnected and generator off.  Also, depending on your coach's wiring, inverter off.

The failure appears to be the neutral wire, that arched, another example of a loose connection, in my HO. Please retighten those lugs on a regular basis! Minutes to do and thousands of $ can be saved. Also please note that multistrand wire is normally used in the manufacture of motorhome, if you or an electrician, replaces those wires, they should always be tinned before inserting them into the lug socket, this practice makes sure that no loose/frayed wires is left dangling to make contact with another lug at a later date, the picture reminds of incidents that I have seen in the past due to a dangling single wire.

[dickandlois]

I have seen a picture like that before !  They build a  house that is driven down the road that can be like putting them in a blender and just seeing what loosens up first.

Rich.

[fagnaml]

Brett, KayP --

I'm totally confused !!   If my Iota transfer switch overheating was the result of loose connections, why then the numerous discussions and safety recalls the last six years about the switch not being properly designed to handle a high electrical load (i.e. two A/C units plus curling iron) under high ambient temperature conditions?   Are you saying "all" transfer switch overheating/fire incidents like mine are the result of poor maintenance by each motorhome / fifth wheel owner that has a power transfer switch?

What about the hundreds of other 120 volt connections in an RV?  Does each connection at each 120 volt outlet need to be checked and tightened?   Does each connection in the 120 volt circuit breaker panel need to be checked and tightened?   What about connections that are not obvious like those or can't be accessed?

In all of my years being around my parents and their travel trailer, four years owning a travel trailer and now 2-1/2 years of owing a motorhome, I don't recall any RV maintenance shop, RV school, etc. ever mentioning the need to inspect/re-tighten 120 volt connections.

Your thoughts and guidance please!

[wolfe10]

I would not use the term "always caused by....".

BUT, loose connections causing RESISTANCE, causing HEAT, causing DEGRADED WIRE AND CONNECTIONS, causing more RESISTANCE.................... IS the most common cause of failure.

Do you see any difference in the type of connections in there vs the ones in a house-type breaker box?  Were these single set screws, stranded wire and no Locktite really purpose-designed to be shaken down the road?

For many years, I have recommended an annual tightening of the screws in ATS and also in the 120 VAC breaker box(s).

[rossboyer]

I do as Wolfe stated in his last paragraph, and I check battery connections, too. Battery connections don’t have anything to do with 120vac, but can effect inverter/charger. 

[hermanmullins]

3 hours ago, fagnaml said:

In all of my years being around my parents and their travel trailer, four years owning a travel trailer and now 2-1/2 years of owing a motorhome, I don't recall any RV maintenance shop, RV school, etc. ever mentioning the need to inspect/re-tighten 120 volt connections.

Your thoughts and guidance please!

I see where inspections are necessary where the heaviest wire are such as the ATS and the Inverter. But one place the is overlooked is your power cable. More especially in the molded plugs. I had a power cord that would work on one coach but not on another coach. I inspected both ends and heat had done a deed on both ends.  Most all electrical shorts are cause by loose are bad connections. So as Brett said Inspect. (ole adage "an ounce of prevention.... ")

Herman

[bm02tj]

It is standard maintenance procedure in high current  industry to dust and tighten connection in the whole plant or mill every year 

That change over box  is high current so needs the same 

[wolfe10]

3 minutes ago, bm02tj said:

It is standard maintenance procedure in high current  industry to dust and tighten connection in the whole plant or mill every year 

That change over box  is high current so needs the same 

And, those boxes are not shaken and vibrated down the road.

[bm02tj]

Some are on machines that vibrate 

[manholt]

Ditto X3.

I and Linda have 3 S&B homes between us...NONE of them move!  We also have 2 coaches, that for many is their home, and they are a Rolling Earth Quake! 

[kaypsmith]

I am not taking up for IOTA or any other company. But as stated loose connections can cause a  lot of problems, overheating is of course one of those. A 50 amp transfer switch is a prime target for problems. The transfer switch uses contacts to transfer power from either generator or shore power. When you see burnt contacts, that is a sign of a faulty contact switch, which can be caused from taking too long to engage, thus burning the contacts over a period of time, or can be misaligned contacts, which in turn are not using all of the surface area, which allows the same condition as not using large enough gauge wire, which in turn causes premature burnout. In your picture, notice the apparent burnout happened on the center set of conductors. Of course we can not see the contacts in the picture, but if that is where the burnout happened, the burned marks would be most likely under those wires instead of on the wires. I also pointed out that most RV wiring is usually multi strand, this is good for the RV industry because the wire is designed to survive those jolts that we can not avoid, but the downside is that it does need to be retightened every once in a while. Most stick and brick homes are stationary and that is why single strand on most smaller gauge romex, as well as the more qualified electricians will always dip the wire in no-lox or similar conductive grease, while those wires that are being installed. Inside conduit is multi strand, it is much larger gauge per strand and will survive longer than what is used in RV's. I have for many years still retorque my house wires about every three years inside the breaker boxes, and renew receptacles and switches every ten years in my home and offices because heating and cooling of electrical conductors happens every time it is called upon for use, this action alone over time will cause poor connections at every junction. No your problem may not be from poor connections, but the periodic maintenance that I am talking about will help in longevity of the electric systems in any circumstance.

[wildebill308]

I do think "tinning" the ends and using a drop of loctite blue (removable) would be a good way to slow the problem. The vibration is why in aircraft they use a terminal swaged on the end of the wire or tined and swaged or with a soldered pin in a canon plug. I have seen few problems with properly installed and safety wired cannon plugs. They could do something like that on an RV for less than maybe $1000.00 maybe 1/2  of that.

Bill

[manholt]

The RV Industry, has in the last 30+ years, gone the direction of cheaper components, for the sake of more profit.  If your coach is listed at $500k, they'll give you 30% off MSRP (feel good money), then you pay $350k, for something that cost $200k+/- to build.  I would much rather see a build Invoice for $300k. 

Bill, I agree in principle, but reality is, if it cost $500 to $1,000....Manufacturers are going to buy the cheapest (China) they can get, so think $50 to $100!  Most of the parts and components are 3 to 5+ years old before it ends up in a coach, installed by a non certified electrician or plumber! 

Most all components on my coach are pre 2006 for a 2010 coach!!! 

[kaypsmith]

What Bill is speaking of is 96% labor, and with an assembly line, slowing down production is very costly. Tinning and swaging all ends would be great, and Loctite on all screws would help. Airplane standards with airplane quality controls would be wonderful, but until that happens, we must all take the little amount of time to be diligent and keep our machinery safe. In most cases, finding the tools to add 1/4 turn on those screws will take longer than actually doing the maintenance. If NASA ever gets involved, those three hundred thousand coaches will actually cost $500,000.00 and no feel good discounts.

[wolfe10]

OK, let's talk about the other (and primary) cause of contacts/points in ATS's burning/pitting:

TRANSFERRING POWER SOURCES UNDER LOAD. Wear on the contacts is quite different if asked to switch with a zero of low amp draw vs 25-20 amp draw,

One of the "best practices" is to NOT be running high loads (like A/C's) when changing from generator to shore power.  Even more important when changing from shore power to generator, as it is best to allow the generator a little warm up time before applying a heavy load.

[kaypsmith]

43 minutes ago, wolfe10 said:

TRANSFERRING POWER SOURCES UNDER LOAD. Wear on the contacts is quite different if asked to switch with a zero of low amp draw vs 25-20 amp draw,

One of the "best practices" is to NOT be running high loads (like A/C's) when changing from generator to shore power.  Even more important when changing from shore

Very true! It would be hard to make a set of contacts that will withstand that sudden transfer under load.

[manholt]

I turn off roof AC about 5 to 10 minutes before, turning generator off.  Then hook up to shore power, and turn on AC again!  Reverse order, when leaving campground.  Made the $993 mistake one time...turning generator off, while AC's was on!  Burned Bushing...Labor was $900 !