Greetings Everyone!Right to the point: I was having trouble with the AC tripping the 15amp breaker (in the home) where we were staying in Florida this past summer. So I jumped on RV.net and searched all the related issues and went down the checklist to try to figure it out. After trying several easy solutions, I finally opened the Power Center to see if there were any issues inside. Upon cracking open the area behind the breakers, I could see a definite problem. All of the ends of the white wires were burnt up, charred and oxidized. I inspected the rest of the assembly and found no more issues that I could diagnose, so I took out all the burnt wires and rewired the unit. It seemed to work better for a little while. Recently, the AC outlets stopped working, so I checked behind the breakers again. I found all the wires to be charred and burned again! I've searched the RV.net forums and couldn't find a solution. Does anyone in this forum know what's going on?Why didn't we smell burning wires?Thanks for your assistance with this!JayHere's a pic of the burned wires.The RV is a 2000 Gulf Stream Conquest Sport.

Wow!I very strongly suggest you replace that load center completely, including the breakers, and a good length of the wires leading into it. The neutral bus has clearly gotten extremely hot, and may be compromised in ways that cannot be seen. It's hard to know what may be happening to the other components, too. Please don't use the AC electric system in the RV until it's been completely taken care of; that's a fire waiting to happen.Heating can often be caused by a poor or loose connection. If the connection has a (relatively) high resistance, there is a fair bit of power being dissipated in a small area when there's a heavy current flow. Maybe the connections were not torqued down properly or worked their way loose, or the contact surfaces weren't clean.Alternately, is there something that might produce heat next to the load panel? Is there a wire that runs there that may be is pinched or chafed?Also, is the outlet in the house a working GFCI, and have you verified that it's wired properly? If there's a ground fault in the RV somewhere, and a hot/neutral reversal in the outlet, you could end up with trouble (that bypasses the RV load center breakers).

Your problem is the plain fact you are overloading the circuit. You CANNOT run a RV AC unit on 15 amp service like you are doing. When you do this, SOMETHING has to give from the heat build up and it is obvious your wiring at the breaker panel is taking the hit. If you did a full research on these forums you would see that trying to run a RV AC unit adapted down to a 15 amp circuit is not the right thing to do. The odds are your buss panel strips in the panel box have oxidized and cannot get a good tight connection when you try to secure the bare wires in the slots/holes. As another poster stated, you need to replace the 120 breaker box panel, cut back the Romex wiring until you get GOOD non burnt wires and secure, then NOT run the Units AC on that house circuit. Doug

Hi,There is too much voltage drop. The low voltage is drawing too many amps.Continuous load on a 15 amp circuit should only be 12 amps.

Look closely at the power section. You may need to only replace the neutral buss bar. You can get them at most hardware stores or electrical supply house.Melted wires are mainly a sign of a loose connection. The neutral buss bars are commonly aluminum. The wire is copper. This is considered dissimilar metals and requires the use of an electrical de-oxidation grease.If you have sufficient slack in the conductors cut the bad ones back to a point where there is good clean fresh copper, install the new neutral buss and re-terminate the wires applying a good coating of de-ox grease.

enbethlen covered the most important parts but you also want to check the connection of the main neutral (white) to the new bus bar. If the main neutral has become loose, it will offer a lot of resistance so that anything connected 120V AC in your rig will have to overcome that resistance. If you've already tried stripping and reconnecting to the neutral bus, it's definitely replacement time.

Need some Power Center help! | Good Sam Community

15 Replies

myredracer
Explorer II
Nov 06, 2014
deleted
enblethen
Nomad
Nov 06, 2014
Op only needs to get new buss bar and reconnect the conductors.
As stated earlier cut conductors back to clean copper, apply good coating of electrical grease and re-terminate.
OP: if not enough slack inside box, there maybe additional wire that can be pulled from behind the power center.
Chris_Bryant
Explorer II
Nov 06, 2014
An air conditioner (or any electrical load, for that matter) could not care less about what size circuit it is on. The *only* thing it cares about is voltage.
120 volts on a 15 amp circuit is fine, 103 volts on a 50 amp circuit is not.

The OP had a high resistance connection on the neutral buss, which overheated and damaged the buss bar and wire. Replacement of the buss bar, and cutting wires back to non-damaged area is what is needed. Nothing external to that buss bar is going to cause that, unless the ambient temp is a thousand degrees.
NinerBikes
Explorer
Nov 06, 2014
Dave H M wrote:
not running the camper AC on a household outlet is totally wrong. it all depends. I been doing it for 14 years now on a 20 amp circuit supplied with 12 ga wire. my ac unit is 13500. :h

OP was running AC on a 15 amp circuit. You never know when your luck may run out and you burn your place down. Just because you've been doing it, doesn't make it smart, safe, right, or to code.
NinerBikes
Explorer
Nov 06, 2014
photo of electrical short damage
Dave_H_M
Explorer II
Nov 06, 2014
not running the camper AC on a household outlet is totally wrong. it all depends. I been doing it for 14 years now on a 20 amp circuit supplied with 12 ga wire. my ac unit is 13500. :h
time2roll
Nomad
Nov 06, 2014
No luck getting the image to work :(

Anyway you probably just need a new bus.
laplata620
Explorer
Nov 06, 2014
Thank you ALL so much! I appreciate all your advice, and I will not use any power until I get the power center completely overhauled and wires sprayed with LPS-3. I feel like I dodged a couple of bullets on this one! Once again, THANK YOU!
Jay
MEXICOWANDERER
Explorer
Nov 05, 2014
There is a reason that aluminum has a shaky reputation and you found it. Aluminum used in electrical has to have coating of tin over it for it not to surface oxidize (aluminum oxide) which has horrible conductivity and turn the aluminum into a toaster-oven faster than you can yell "Where the hell is the fire extinguisher?"

A buss that burned a wire (even if the fault was a loose or overloaded wire) should have the repaired wire switched to an empty hole. If none exist, I recommend changing out the buss.

When things are repaired perfect and are ready for assembly, use NO-OX a solution sold in Electrical Supply houses and Home Depot. Follow directions.

Use the rig for a week, shut off all power or disconnect, then re-tighten ALL set screws in the power center. The re-tightening is a must.

Because I live where the very air is toxic to electrical connections (hundreds of meters from the pounding tropical pacific ocean) I have to coat exposed conductors with a protector spray. WD40 is useless. LPS-3 (not 2, or 1) is a good protector.

But copper wire ends must be shined to resemble a brand-new copper penny. I use a new utility knife blade and rotate the wire.

Every single wire in that cabinet should be pulled one-at-a-time and examined. The slightest hint of overheated insulation means the device the wire is connected to must be replaced. Oxidized aluminum buss bars and connectors CAN NOT be shined-up and re-used. They have to be replaced with aluminum parts that have the tin coating.

Hope This helps.
Blackdiamond
Explorer
Nov 05, 2014
Also the AC needs to be on a 30amp, so your trailer plugged into the house should be an a 30 amp circuit, not 15 amp, that is why it is overheating and may have caused other issues with the load center.