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Old 10-17-2019, 05:47 PM   #1
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Converting 310 Classic 30amp to 50amp

I am in the process of swapping my 30 amp service to 50 amp service and was wondering what setup did anyone use while converting to 50amp. Did you straight wire your shore power to the 50amp transfer switch or install a twist lock 50amp male plug since the old wires from the 30amp need replaced. Looking at running four #6 wires from a male twist lock plug to the transfer switch so the shore cord could be disconnected and rolled up and placed in the compartment without a twisted mess. Does this sound logical to do. Any recommendation will be appreciated. 50amp transfer switch will be located where the old 30amp currently is in the rear street side compartment.
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Old 10-18-2019, 05:36 AM   #2
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Converting 310 Classic 30amp to 50amp

My 360 Classic came from the factory with 50 amp. It has a marine type twist lock. I like that configuration. The 50 amp cord can be an uncooperative python to stuff in a cabinet. Especially when cold and stiff. It would suck if it was hardwired in and got pulled out for some unimaginable reason. Like the door opening and the cord falling out while driving down the road. Saw that on a trailer once. No one would ever drive off with the power connected!
Or drive over your cord and snag it with a golf cart pulling a full honey wagon. Don’t ask!


I also installed a Progressive dynamics transfer switch with built in protection for spikes, under/over voltage...

Really like it.
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Old 10-18-2019, 06:13 AM   #3
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Quote:
Originally Posted by cole3444 View Post
I am in the process of swapping my 30 amp service to 50 amp service and was wondering what setup did anyone use while converting to 50amp. Did you straight wire your shore power to the 50amp transfer switch or install a twist lock 50amp male plug since the old wires from the 30amp need replaced. Looking at running four #6 wires from a male twist lock plug to the transfer switch so the shore cord could be disconnected and rolled up and placed in the compartment without a twisted mess. Does this sound logical to do. Any recommendation will be appreciated. 50amp transfer switch will be located where the old 30amp currently is in the rear street side compartment.

I suspect that folks are reluctant to reply to your question, because of the different wiring options Airstream used, especially in the 310 models.
Since you also have to consider the 30/20 amp circuit coming from the generator, I would proceed with great caution and consult a licensed electrician with knowledge of RV circuitry. The method some of us have used, is adding a dedicated 20 amp (or even 30amp) circuit for the rear AC, which should be protected by an onboard circuit breaker as well as a transfer or manual switch to separate the circuits fail proof . Instead of using a new 50amp twist on, you would use a 50 amp "dog bone" (splits into 2 30 amps) and have 2 plugs coming out of your MH.

The benefit of this set up is your ability to plug into 50/30/and even 20 amp as needed.
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Old 10-18-2019, 06:26 AM   #4
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This is the transfer switch I used:

https://www.progressivedyn.com/rv/au...he-silent-ats/

Make sure you get one with DC coils or it will hum you to sleep.
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Old 10-18-2019, 04:42 PM   #5
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I did what Peter suggests in his post. I added a second shore power cord dedicated to the rear air conditioner and one outlet. Also added a small two breaker panel for that circuit. The panel and outlet are mounted on the inside, next to the generator enclosure. This way I can run the rear ac off shore power or the generator OR I can use the outlet for supplemental electric space heating. Was a pretty straight forward mod, didnt have to get into the transfer switch or much else. All I did was locate and interrupt the circuit from the generator to the rear ac. That was in a junction box near the generator enclosure. Less than $150 total I suppose for the #10 cord, 2 breaker panel n breaker, outlet box n outlet, male end for the cord.
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Old 10-18-2019, 05:18 PM   #6
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mayco,
My 30amp transfer switch is shot, not sure how long it has been bad, my electrical guy found the transfer switch contacts burnt up. The PO had emails with two different drawings in my manuals that were from Bkahler1 and Tony from the forums dated back in 2012 showing him how to wire a second cord to the rear A/C with a light switch transferring from shore to generator which worked but no transferring capability. He found some wires that were also disconnected so he wants to start over with a 50amp since the cost is just a bit more than the 30amp at Best Converter, might as well upgrade now before my electrical man goes nuts from the way Airstream ran and connected wiring. Looking at the one Kota posted. Trying to make it easier for the wife to set up also. Thanks all for the input.
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Old 10-18-2019, 05:35 PM   #7
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If you follow my thread back 2 years you will see how I converted the 370LE from the original 30 amp service to 50 amp service. Earlier in the 325LE “It’s Never Done” thread I made an inexpensive 30 to 50 amp conversion by simply putting a plug “50” amp in the generator compartment. When I got to a campground that had 50 amp I would simply unplug the generator and plug in a 50 amp extension cord.....done. Regards, Bob
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Old 10-18-2019, 05:56 PM   #8
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Quote:
Originally Posted by cole3444 View Post
mayco,
My 30amp transfer switch is shot, not sure how long it has been bad, my electrical guy found the transfer switch contacts burnt up. The PO had emails with two different drawings in my manuals that were from Bkahler1 and Tony from the forums dated back in 2012 showing him how to wire a second cord to the rear A/C with a light switch transferring from shore to generator which worked but no transferring capability. He found some wires that were also disconnected so he wants to start over with a 50amp since the cost is just a bit more than the 30amp at Best Converter, might as well upgrade now before my electrical man goes nuts from the way Airstream ran and connected wiring. Looking at the one Kota posted. Trying to make it easier for the wife to set up also. Thanks all for the input.

Ahhhhhhh, ya, I forgot your transfer switch was shot. Yup, might as well upgrade the whole system now. (My head is still driving, we just got off the road a couple hrs ago.)
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Old 10-18-2019, 06:02 PM   #9
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Originally Posted by bobmiller1 View Post
If you follow my thread back 2 years you will see how I converted the 370LE from the original 30 amp service to 50 amp service. Earlier in the 325LE “It’s Never Done” thread I made an inexpensive 30 to 50 amp conversion by simply putting a plug “50” amp in the generator compartment. When I got to a campground that had 50 amp I would simply unplug the generator and plug in a 50 amp extension cord.....done. Regards, Bob

The later 80's and early 90's came with 2 transfer switches from the factory. The early 80's (310 models) came with just transfer switch at the 30 amp entry. Switching of the AC's was controlled by various mechanical switches. Adding a 50 amp plug at the generator alone will not solve it.
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Old 10-18-2019, 08:26 PM   #10
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Hi

To do a "proper" 50A setup you need:

1) A 50A 240V electric panel and 50A 240V main breakers
2) At least one 50A / 240V shore power input connector to power that beast
3) Wiring of the existing loads into a "split" configuration ( half on one side, half on the other) into that box.
4) Appropriate brand / make / type of breakers for that box and those loads
5) A GFI breaker to feed the stuff in the kitchen (or GFI outlets)
6) With an onboard generator, you should do a 50A 240V transfer switch, regardless of generator size.
7) With multiple power inlets, you would need multiple transfer switches.

None of that is crazy hard to do. It's no different than wiring up a house or a shed. It does take time and money. You do need to understand what you are doing.

Bob
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Old 10-18-2019, 08:32 PM   #11
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Bob,
I will be searching your thread for the 30 to 50 amp conversion but had a big question on installing the 50amp transfer switch, when connecting the 50amp shore power cord to the transfer switch, connecting the 120/240 breaker panel with an adding an additional 20amp circuit breaker for the rear air wiring to the transfer switch terminals and connecting the 6500kw generator wires to their terminals on the transfer switch want this setup allow both my A/C units to run at the same time with either the generator or shore power. This is what my electrical guy explained to me. He said all wiring is still good just hard to access in the rear. I will be installing a twist lock plug in the compartment so the shore cable can be curled and stored easier. My concern is a junction box under the closet by the bed that has a mess of wires and wire nuts where the PO had connected the rear A/C power cord into and where the generator wiring came in. Looks like a short waiting to happen and it has to go. Please let me know
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Old 10-18-2019, 08:39 PM   #12
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Quote:
Originally Posted by cole3444 View Post
Bob,
I will be searching your thread for the 30 to 50 amp conversion but had a big question on installing the 50amp transfer switch, when connecting the 50amp shore power cord to the transfer switch, connecting the 120/240 breaker panel with an adding an additional 20amp circuit breaker for the rear air wiring to the transfer switch terminals and connecting the 6500kw generator wires to their terminals on the transfer switch want this setup allow both my A/C units to run at the same time with either the generator or shore power. This is what my electrical guy explained to me. He said all wiring is still good just hard to access in the rear. I will be installing a twist lock plug in the compartment so the shore cable can be curled and stored easier. My concern is a junction box under the closet by the bed that has a mess of wires and wire nuts where the PO had connected the rear A/C power cord into and where the generator wiring came in. Looks like a short waiting to happen and it has to go. Please let me know
Hi

If your generator puts out 240V then it's a pretty simple process. If your generator only puts out 120V it's not quite so easy.

With a 240V generator, it just hooks to one input on the 50A 240V switch. The shore power goes to the other input on the switch. One A/C goes on one side of the 240V, the other A/C goes on the other side of the 240V. You can run them both at the same time, as long as the generator is big enough. When you go to shore power, the transfer switch does it's thing and all works same / same.

Bob
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Old 10-20-2019, 11:30 AM   #13
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Thanks everybody, generator is 240v .GE breaker box 120/240 My electrician was wondering if anyone has replaced the wiring coming up through the wall to the 120/240 breaker box from the transfer switch on the 310's. Trying to see if they run underneath or through the walls. He was looking at possibly replacing the wires so their are some slack to work with but all both of us see is floor and belly pan and doesn't want to drill through wires that are unseen. He loves Airstreams high tech ways. I have almost got him converted from wiring nuclear power plants to wiring Airstreams, haha. Thanks Jim
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Old 10-20-2019, 11:54 AM   #14
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Quote:
Originally Posted by cole3444 View Post
Thanks everybody, generator is 240v .GE breaker box 120/240 My electrician was wondering if anyone has replaced the wiring coming up through the wall to the 120/240 breaker box from the transfer switch on the 310's. Trying to see if they run underneath or through the walls. He was looking at possibly replacing the wires so their are some slack to work with but all both of us see is floor and belly pan and doesn't want to drill through wires that are unseen. He loves Airstreams high tech ways. I have almost got him converted from wiring nuclear power plants to wiring Airstreams, haha. Thanks Jim
Only place, i have seen wires under the floor board is at the service entry. Everything else should be in the walls/ceilings. But then you never know what a previous owner may have done.
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Old 10-21-2019, 06:34 AM   #15
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This guy explains it better than I can.

https://www.rvtechmag.com/tech/39_tutorial.php

My 50 amp 360 is wired just like a house. 2 pole breaker panel with 120 volts each pole to neutral and 240 volts across the poles. The box is fed by the 240/120 transfer switch. You could put a double breaker in the panel and have a 240 volt circuit just like your 240 volt appliances in your house. As long as you are on 50 amp shore power that is.

Since there are no 240 volt circuits in most coaches like mine it doesn’t matter in both poles are powered by the same 120 volt source. This the case when you use an adaptor to plug your 50 amp cord into a 30 amp outlet. Or in most cases run off the generator. Most RV 240/120 generators are wired with the fields in parallel so the two poles are essentially ties together to balance the load in generator.

The tech article explains it pretty well.
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Old 10-21-2019, 08:03 AM   #16
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Converting 310 Classic 30amp to 50amp

Important to note that the two poles are tied together in the adaptor plug or generator. When plugged into 50 amp and through the transfer switch the sides must not be tied together. Or you will have a dead short across the poles.

L1 and L2 tied together in the generator will be isolated by the transfer switch.

Just wire in the new breaker box as you would your house. Balance you’re breakers so you have similar load on each pole.
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Old 10-21-2019, 11:17 AM   #17
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Here are a couple pics of my breaker box and the terminal box under the cabinet by the bed. The romex had run from the rear A/C to the switch that was wired into the wad of wires inside the box to swap from gen to shore. I have got the romex ran from the breaker now to the romex that goes to the rear air, will tie it together when I get the 50amp in.
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Old 10-22-2019, 09:33 AM   #18
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Hi

If you tie both hot lines of a 240V / 50A together, they indeed will be happy current wise. The gotcha is the neutral wire. With "proper" 240V the hots are out of phase. With a full 50A load on both sides, there is zero current in the neutral ( out of phase adds to zero). With only one side loaded, you get 50A in the neutral. That's what the cable / connectors are rated to handle.

If you drive the hots together (in phase) *and* fully load both hot circuits, you will get 100A in the neutral. That's 2X what the wire / connector is rated for. Since heat goes up as the square of current ( I^2*R) this is a 4X "to hot" sort of situation. You can damage things this way.

Will you ever pull > 50A (= sum of the two hot lead currents) in *your* RV? That's very much a "that depends" sort of thing. I certainly can / have / will again pulled more than 50A total in mine. Can I pull 100A in mine? nope.

Be careful !!!!!

Bob
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Old 10-22-2019, 10:51 AM   #19
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I have been trying to find a Square D breaker box that will fit where my old one is but no luck so far just to be on the safe side. Currently my 50 amp is mounted in the top of the box and the two A/C units are on separate legs of the box. The big problem is the lack of slack on the wires coming into the breaker box to move the breakers round. That is why my electrician asked how the wires are ran. I guess I am going to have to take a little interior sheeting loose to expose how the wires run. I just want to be able to run both A/C units when it gets hot here in the southeast and not cause a issue. Waiting on my 50 amp transfer switch. I appreciate all the feedback, I just hope my electrician keeps coming back
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Old 10-23-2019, 10:44 AM   #20
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Here’s some pictures of mine as the factory set it up. I replaced the transfer switch.

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I like his so I can close the lockers while plugged in.

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Wired like any two pole panel.

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