Older Class A Electrical

[Dmeyer07]

Hi.
I have a new to me 2000 Damon Intruder 341 Class A Motorhome that has a 50 amp setup.
50 Amp shore power plug in
7000 watt onan on board generator
(Adding 2000W 110 inverter)

And a "TODD" Automatic transfer switch (pictures attached)

I've got a couple of questions:

1. *Ignore, refer to reply below*

2. Why does this ATS refer to itself as a 120/240 ATS- is it because there is 2 hot 110 leads and 1 neutral? Technically 240 but is anything actually running 240 or putting out 240 (generator?).

3. I'm installing an inverter. Can I just install an ATS where the generator leads connect to the stock ATS, and have the inverter and generator come into my add on ATS, then go out to the generator input on the stock ATS?

I am not a complete noobie when it comes to electrical, I've been in the maintenance field for over 20 years, so please don't say hire an electrician. I just want to clarify a few things first because I'm not up on the older RV's with 50 amp service. Perhaps they did things a bit differently 23 years ago!

Thanks for the help

Picture 1


Picture 2



Picture 3


Picture 4

[Dmeyer07]

I have wired up the new ats generator in one side inverter in other side and output going to the todd ats generator spot. Works perfectly.
Now at the request of everyone I've ordered another ats and will be swapping out the todd. Ps 50 amp wiring in this tight little space sucks!

[SuperBus]

oldave wrote:
I see you have an old Todd transfer switch ( ATS ) I urge you to not use it, they are dangerous, a fire hazard. Todd was originally Iota. Iota was a fire
hazard and was recalled, went bankrupt, and reappeared as Todd still the same old switch. Todd is now out of business. I took my Iota out and replaced it with an Esco. Take a look at this thread.

https://www.irv2.com/forums/f103/50-amp-automatic-transfer-switch-power-switch-99403.html

Ditto! Get that TODD out of there immediately.

I had a TODD ATS in a coach. I had it in the drive a few nights before a trip and happened to go outside to get something from, or put something into the coach. I smelled an odd odor and began to investigate. When I got to the electrical bay, smoke poured out when I opened the baggage door. It was my TODD switch in the middle of a meltdown. One of the relays had shorted. Whether or not it would have caught fire, who knows but it freaked me out. Thank goodness I happened to go outside that night, or I might have woke up to a 45' long inferno later on.

[wa8yxm]

dougrainer wrote:


PS, yes your added pic shows the ROUND detachable 50 amp shore cord. BUT, your shore cord male end should have 4 pins.

It does have 4 pins you can't see the 4th less you know where to look.

On the 30 there are 3 blades. All in the circle.
On the 50 there are 3 blades in the circle and th 4th contact is on the OUTSIDE of the plug. It's a metal strip that connects with what looks like a ball bearing in the side of the inlet.

I see the poster figured it out. IT is about th4 7 O'Clock position in the photo.

[CA_Traveler]

#3 Consider wiring so that both ATS default to the inverter to minimize battery power drain.

[RLS7201]

#3 I did just as you suggested. Installed a transfer switch and inverter in the generator line. When the inverter is on my MH thinks the generator is running and I must manage energy usage.

Richard

[MrWizard]

The Todd has 2 contactors/relays with mechanical interlocks, once either shore or generator power is hot the other input cannot be engaged, there was one in my Safari DP, i always thought of it as a quality product, I make it a point to switch off high draw loads like the A/C before switching between shore generator or inverter, i will run the MW from inverter but not the A/C
I recently replaced my Failed addon ats which was a Southwire 30amp RV ats, when it failed i replaced it with this one from Amazon



2 pole 120v 63amp
While not advertised for RVs, there is no enclosure box, I'm very happy with it ,
Yes there is a 240v model available ,
Main power input is default aux power input is for generator or inverter , main power is dominate and will overide and automatically switch back when shore
power returns ( if the Manual - Automatic Rocker is set to Automatic.), it is motor driven and break before make the two input sources never come in contact,
It also has Manual Mode Operation, there is Rocker switch to choose automatic or manual mode, put the rocker on manual and turn the big Blue Handle to the power option you want, great if shore power is being intermittent during or after a storm, set to manual switched to aux input using inverter it will stay there and not switch back and forth because of shore power blips ,

[Dmeyer07]

Thanks everyone for the replies! I learned a bunch already.
That's crazy to hear about the transfer switch ugh
I'll be doing a whole house inverter setup,I'm aware of what it can and can't power as this is how I've had my last two rigs setup. I always turn the converter off and then inverter on and turn the AC breakers off. It can power everything else and yes I do use the electric water heater even!
I run 2 gauge ofc short run to my inverter, it's a high quality pure sine wave (but not pass through) setup.

[wa8yxm]

Dmeyer07 wrote:
Hi.


2. Why does this ATS refer to itself as a 120/240 ATS- is it because there is 2 hot 110 leads and 1 neutral? Technically 240 but is anything actually running 240 or putting out 240 (generator?).

You got it. the ATS works on either 120 or 240 volt systems.. Don't worry about that. The generator likely only puts out 120 volt by the way.. Just so you now (Not guaranteed but common) the L1-L2 voltage is zero or very low.

3. I'm installing an inverter. Can I just install an ATS where the generator leads connect to the stock ATS, and have the inverter and generator come into my add on ATS, then go out to the generator input on the stock ATS?

NO.. you really should either get an inverter with pass through or install a 2nd Sub panel" With a inverter of 3600 watts or less I'd go with a 30 amp RV type Sub panel and a 30 amp ATS.. Feed the GENERATOR Terminals on the ATS (yes the generator leads) from a 30 amp breaker in the MAIN Breaker panel The Inverter hooks to the "SHORE" terminals.

Why. This will cause the switch to switch to SHORE when you have it and drop back to INVERTER when you do not.

If you get an inverter with a built in transfer switch (Best kind) They can be set in UPS mode.. a Television or microwave won't even blink.

YOU DO NOT want the inverter powering the water heater. Air Conditioner or the Converter...

Another option is an INVERTER/Charger.. Install as above but disable the converter. that is on the rig now. Odds are the "Charger" part of the inverter is way better than most low end converters


And good luck.. Be sure to use heavy enough wire and enjoy.

[oldave]

I see you have an old Todd transfer switch ( ATS ) I urge you to not use it, they are dangerous, a fire hazard. Todd was originally Iota. Iota was a fire
hazard and was recalled, went bankrupt, and reappeared as Todd still the same old switch. Todd is now out of business. I took my Iota out and replaced it with an Esco. Take a look at this thread.

https://www.irv2.com/forums/f103/50-amp-automatic-transfer-switch-power-switch-99403.html

[ScottG]

With a 7KW genny, you'll have a 50A 120/240 shore power connection, which has 3 pins and a side connection on its twist-lock and 4 pins at the male end.
I agree with Ca Traveler, just go with a 120V inverter - there's nothing in your rig that needs 240VAC.

[CA_Traveler]

You seem to be suggesting some type of whole house setup with the inverter. Suggest keeping it simple with a new 120V circuit for the inverter.

[dougrainer]

Post a Pic of the Motorhome plug in receptacle and the END of the Shore Cord showing the 3 spades. 50 amp shore cords the ends have 4 pins, period. They did NOT do things differently 23 years ago. I will bet a previous owner modified the 4 spade shore cord to just have 30 amp cord end. Doug

PS, yes your added pic shows the ROUND detachable 50 amp shore cord. BUT, your shore cord male end should have 4 pins.

[Dmeyer07]

Never mind I see how they've got it set up the ground is on the outside of the plug duh
https://photos.app.goo.gl/3oTgAmXQQjGqS6mB6

https://photos.app.goo.gl/pAYdMuP7MPi5Db7v8

[Rick_Jay]

Hi Dmeyer07,

Congratulations on your first post on the Forums!!! 🙂

1.) YES, your 50A shore power plug should have four conductors at each end. Two hots (L1 & L2), a neutral and a ground. Any properly wired campground you go to with 50A service will have a 50A receptacle for a 4 prong plug. Personally, I would CORRECT this issue IMMEDIATELY. This could be a safety issue and depending upon how it's wired, you might be jeopardizing the electrical appliances in your motorhome. (See additional comments below about it being wired for 30A service only.)

2.) 50A service is 120V/240V service. The vast majority of RV's internally use the connection as two 120V, 50A lines sharing a neutral. There will be 240V across L1 and L2 (L1 and L2 are 180 degrees out of phase with each other), but there will only be 120V between either L1 or L2 and Neutral. Your generator is also 120V. It puts out two 120V hot lines, but they are in-phase with each other, so you won't see 240VAC across the generator hot lines. You'll see approximately 0V across the two generator hot lines. Most likely nothing in your RV uses 240V. However, some newer, mostly high-end rigs, DO have 240V appliances with 240V generators as well.

3.) I'll let someone with more experience with inverters answer this question. 🙂


50A RV service is the exact same service you will see on a modern 50A electric range or electric dryer outlet in a house. Same NEMA receptacles and plugs.

Thinking more about your 3 conductor plug...I think it's likely the previous owner decided to only use a 30A connection to the rig so he wouldn't have to handle the extra heft of a 50A shore power cord. Can you post a picture of the plug? The 50A cord uses much heavier gauge wire and the cables are definitely much heavier, bulkier and harder to wind up, especially in cold weather. The previous owner might never have needed anything other than 30A, so they just used a 30A cord. (30A service is one hot, one neutral and a ground.) If this is the case, you'll be OK to use it. It's not a safety hazard or a hazard to the appliances on the rig. BUT you'll only have 30A of electricity available.

You probably know this, but just to be complete. A 30A service can provide up to 3,600 Watts of power to your RV (120V * 30A =3,600W). A 50A service can provide up to 12,000 Watts of power to your RV (2*120V*50A=12,000W). So there IS a noticeable difference in available power between the two systems.

Good Luck,

~Rick