Rewire/upgrade 30 amp to 50 amp

[underdog42]

I have a 99 Pace Arrow by Fleetwood and would like to know it antone has any knowledge of what it takes and where I can go to get a rewire/upgrade to 50 amp. I'd like to say that cost is of no consequence but cost is very important.

 

[Gary RV_Wizard]

A 50A upgrade is not all that difficult if your objectives are limited. Most rigs like yours with 50A service basically just run the second (rear) a/c off the second "leg" of the 50A service and run the rest of the coach on the other "leg".  Since each leg of a 50A circuit provides 50A, that essentially provides 50A where you had 30A before and runs a second ac unit besides.

You need to replace the shore power cord with a 50A,  3 conductor+ground cable. Your current load center is fed with the sigle "hot" lead of a 30A power cable and just one of the 50A hot leads will do th same chore. The other can feed the rear a/c , if it is run throgh a 20A circuit breaker.

If you want more than the existing 30A power to your interior outlets, you will habe to replace the RVs load center, add a 50A main breaker and probably do some interior re-wiring to actually deliver the available power where you want it.  50A at the load center does little good when the coach has evey single outlet wired to one (or maybe two) circuit breakers. You haee to re-wire to take advantage of the greater power available with 50A serive.

So let's back up and may I ask what leads you to want to upgrade?  There may be alternatives that will solve your problem without the expense of a full 50A servce upgrade.

 

[blueblood]

I I'd like to say that cost is of no consequence but cost is very important.

So, why are you doing it ?

 

[Shayne]

I'm thinking the same thing.  othing in that unit warrants  the use of 50 AMP.  If it did it would have been installed previously at the factory.  Could wind up ruining the entire unit if not properly skilled and using the proper equipment.  I've used 30 AMp for years and can't find any reason to alter it, even with all the tools I utilize including Computerized digital automatic powered radial arm saw in the trailer, along with an electric heater in the trailer.  This is all behind the MH.  Can't understand the thinking unless too much time and wondering mind that has to experiment./  JMHO

 

[Karl]

Hot, humid weather and the need to run 2 a/c's at the same time. I can understand it. And running all those high pressure vapor lamps to grow who-knows-what... ;D ;D ;D

 

[Gary RV_Wizard]

If it did it would have been installed previously at the factory.

Ah Shayne, you have much greater faith in RV manufacturers than I do!  :

I've seen a number of gas motorhomes built with 30A service but loaded with enough electrical gear to tax a 50A system. Two a/cs are pretty common; add to that a convection oven, electric water heater, big fridge, and a 50A converter and 30A isn't even close.  Pace Arrow, for example, didn't even offer a 50A option on their MH in 2004, yet they build 'em up to 37 feet with 3 slides and all the trimmings of a high end DP. Go figure...

 

[blueblood]

Ah Shayne, you have much greater faith in RV manufacturers than I do!  :

I've seen a number of gas motorhomes built with 30A service but loaded with enough electrical gear to tax a 50A system. Two a/cs are pretty common; add to that a convection oven, electric water heater, big fridge, and a 50A converter and 30A isn't even close.  Pace Arrow, for example, didn't even offer a 50A option on their MH in 2004, yet they build 'em up to 37 feet with 3 slides and all the trimmings of a high end DP. Go figure...

FW generally used a power shedding device on their motorhomes until about 2001. I had 2 ac's on my 36' 99 Discovery w/lg slide as well as the other good stuff like washer/dryer, etc. I never had a problem with its operation. It would shed until the one ac was going , then start the second and then both would run without problems.

 

[underdog42]

I asked the question to see what you experts thought.
The problem is 37ft one slide, converter 30amp, small freezer 5 cu ft, 13.5 a/c and 11.0 ac.
On any normal day with both a/c's smoking to cool down west Texas hot air and shedding the rear on when mom uses the micro or coffee pot the viltage will pull down to as low as 104-100.
As we all know no RV spot has low power to start with so it must be my unit ............right?
All BS aside it is to run the rear a/c unit off the other leg.
I'm with you... the industry will build and sell whatever they can get away with and their RISK MANAGER will sign off on. Buyer be ware.
I like to do it by the book so the next question to the experts is......is it wtitten anywhere that you know of how to oroperly change out the shore lead and then seperaye the rear A/C?
WORKING WITH ADD AND OLE TIMERS IS A HANDYCAP. Thanks

 

[Shayne]

Thats what we have is a 37 ' Pace Arrow and never had a problem , so thats the reason for my statement cuz I load it down with power uses more than the average guy would even think of doing.

 

[Karl]

It shouldn't be too difficult. The following steps are general in nature; other rigs may be slightly different. The 30A service coming in, the heavy cable, will terminate in a junction box somewhere and connect to the (probably) 12ga. wires going to the main breaker panel inside. Somewhere very near there I would install a separate, new 50A/240V breaker panel (a small one will do) to hold the new 50A main breaker and a few smaller ones; one for the second a/c unit. Wire the new 50A cable into the existing junction box and connect ONE of the hot leads, the neutral, and the ground to the existing wires going to the main breaker panel. Again from the existing junction box, run a 3-wire, 12ga. (hot, neutral, and ground) cable from the OTHER hot lead, the neutral, and the ground, to the new breaker box, connecting the hot lead to the 50A breaker, the neutral to the neutral bus bar, and the ground to the ground bus bar. Now the fun begins. A new 3-wire, 12ga. cable must be routed from the new breaker box to the a/c unit. This could be easy or extremely difficult and I don't have any specifics on how to make it easy. Once that's done, remove the old hot wire from its' existing breaker in the existing breaker panel and seal it off with a wire nut and electrical tape, and attach a label to it explaining what it was originally for and why it's not used.  Make reference to the new breaker box so someone can find it should it become necessary. Do the same with the hot wire at the a/c unit. Now double check all wiring, make sure all connections are proper and tight, measure for any shorts or opens with a meter, make sure all grounds are truly grounded. Once convinced everything is o.k., install the new, proper size breaker in the new breaker box, connect the hot lead to it, and give it the smoke test! 

This will provide 50A service to the new breaker while retaining the original 30A service for the rest of the coach. After trying to trace out a route for the new wiring to the a/c unit and finding it too difficult, it may be easier to bite the bullet and upgrade the whole coach to full 50A service. This would also require a new 50A cable, new 4-wire (or two-3-wire) cable from the junction box to the breaker panel, a new 50A/240V breaker panel, and moving all the existing load wires from the old box to the breakers in the new one. At the same time, determine the load each load wire carries so the loads can balanced between the two 120V hot sides of the 50A service.

Disclaimer: I am not a licensed electrician. The above is intended only to show the methods I would employ to upgrade my own coach, and is in no way meant to be a recommendation or be used as step-by-step instructions. I recommend the use of a licensed electrician, but should you choose to do it yourself, it is entirely at your own risk.   

 

[Gary RV_Wizard]

I would do it as Karl suggests, with a minor enhancement: Add another 15A or 20A circuit off the second  a/c side of the 50A input and use it to power some new auxiliary outlets, which I would locate wherever I could manage them, inside and out. That would give you some extra 120VAC power for extra gear, e.g. an electric heater for a cold night or maybe your freezer.

As for the voltage drop when you hook up, THAT is a problem with park power, not your rig. If your main breaker doesn't trip,  and the power pedestal breaker doesn't trip, you aren't drawing more than your allotted 30A and the park power pedestal should be able to supply the full 30A without a significant drop in voltage. Complain to the park management about inadequate power.  Running your a/c with voltage under about 105 will damage it sooner or later.

 

[Karl]

Gary,

Thanks for adding that about the extra circuits. I alluded to it by saying "50A main breaker and a few smaller ones", but neglected to expand on it. Another use might be for some small lights in the bays to prevent water freeze-ups. It's supposed to get down to 20F here tonight!!! And this is Arizona? Right now it's so windy that the hummingbirds have to execute several missed-approaches just to get a drink from the feeder!

 

[Weewun]

Again from the existing junction box, run a 3-wire, 12ga. (hot, neutral, and ground) cable from the OTHER hot lead, the neutral, and the ground, to the new breaker box, connecting the hot lead to the 50A breaker, the neutral to the neutral bus bar, and the ground to the ground bus bar.

12 gauge wire is insufficient for 30 amp service.  Suggest that you use a length of the existing supply cable that is already connected to the incoming supply box to run to the new 50 amp breaker box you install .

 

[Karl]

12 gauge wire is insufficient for 30 amp service.  Suggest that you use a length of the existing supply cable that is already connected to the incoming supply box to run to the new 50 amp breaker box you install .

Yes, it is. Rated ampacity for 12ga. wire is 41 amps for chassis wiring. 10ga is o.k. for 55A chassis wiring.

 

[Weewun]

Yes, it is. Rated ampacity for 12ga. wire is 41 amps for chassis wiring. 10ga is o.k. for 55A chassis wiring.

Muat be reading a different spec book than I am,  I believe that if you check you will find tha the cord going from the MH to the 30 amp Park service is, at a minimum, 10 gauge.

 

[Karl]

I believe that if you check you will find tha the cord going from the MH to the 30 amp Park service is, at a minimum, 10 gauge.

That may be true, even probably on the low side. If you use the 700 circular mils per amp rule for power transmission, a 12ga wire would only be rated for 9.32 amps - very, very conservative. Don't forget I suggested the new box be located very close

Somewhere very near there I would install a separate, new 50A/240V breaker panel

, and being in free air and not bundled or in HVAC ducting, the 700 rule does not apply. I agree that bigger is usually better, but we're talking about the difference between a .636 volt drop per 10' of 10ga. wire as opposed to a .932 voltage drop for the same length of 12ga. wire when loaded to 30A@120VAC. Hardly worth mentioning. Besides, 10ga. is a whole lot harder to work with.

 

[Gary RV_Wizard]

Don't fight, children.  The ampacity of the wire depends on its type of insulation and how it is installed. And whether it is solid or stranded.

 

[underdog42]

Well! first of all thank all of you whom have had something to say. I am now better informed and ready to do work. sounds almost as easy as I was told by an electrician friend. We will work on it together later in the spring.
Over/and out.