AC Power Junction Box

DancinCampers · 05-18-2006, 01:32 PM

At our WIT chapter (Vegas Rollers) outing last weekend one of our members lost AC power to their Class C Winnie. This coach does not have an Auto Transfer Switch, but a seperate plug outlet for the generator. They were on shore power, everything working, then no AC in coach.

The problem ended up being in the junction box where the power cord is connected to the coach wiring which goes to the AC breaker panel.

The coach hot wire insulation was burned back about 2 inches & the wire nut was melted. The neutral wire nut was melted.

Good thing Winnebago installed this in a METAL junction box.

The coach is about 7 years old.

If you have this type setup it would be worth having a look at it.

DancinCampers · 05-18-2006, 01:32 PM

At our WIT chapter (Vegas Rollers) outing last weekend one of our members lost AC power to their Class C Winnie. This coach does not have an Auto Transfer Switch, but a seperate plug outlet for the generator. They were on shore power, everything working, then no AC in coach.

The problem ended up being in the junction box where the power cord is connected to the coach wiring which goes to the AC breaker panel.

The coach hot wire insulation was burned back about 2 inches & the wire nut was melted. The neutral wire nut was melted.

Good thing Winnebago installed this in a METAL junction box.

The coach is about 7 years old.

If you have this type setup it would be worth having a look at it.

RV Wizard · 05-18-2006, 11:41 PM

National electrical codes require that all connections of ac wiring be inside an approved junction box to contain this event if a loose connection accurs. It would be something that someone may want to look at as well as the main feeder lugs at the distribution panel. If they are tight connections you should not have to worry about them from that point on. Aluminum wiring is no longer used and is not approved for the reason that it would loosen over time; copper wiring will not. I would also advize that everyone be very careful not to oversize the service on a 30 amp shore power cord by the use of an adapter plugged into a 50 amp receptacle. This could melt the insulation and damage the cord if more than 30 amps of current are constantly being used. Good luck to all and stay safe.

Kazoo Tom · 05-19-2006, 09:04 AM

Good advice RV Wizard. However I do frequently use my 50 to 30 "dogbone" to be able to get the full 30 amps from some campgrounds. Generally only when it is very hot and need both a/c units to operate. My coach is a 30 amp system and is designed to run both off 30 amps. We have been in many campgrounds where the 30 amp connection actually delivers less than the full 30. My main breaker is 30 amps, so if the power becomes greater, I believe the breaker should protect the system. Isn't it true that the "dogbone" only taps one 120 volt side of the 50 amp circuit anyway?

Ed Gardiser · 05-19-2006, 05:51 PM

Tom
Yes you are correct concerning the "dogbone" only taps one 120 volt side of the 50 amp circuit.Also the 30 amp circuit breaker in the coach will limit the amperes coming in from the 50 amp service.If for some reason the coach is drawning more than 30 amps that breaker will or should trip off protecting the cord.
Ed Gardiser
Escondido,Ca.
04 Vectra
87 Nissan PickUp
FMCA

Kazoo Tom · 05-19-2006, 06:44 PM

Thanks Ed, I was hoping someone would confirm that for me. I've actually been to several campgrounds where the 30 amp connection wasn't delivering the full 30 amps. The dogbone has "saved the day" for us.

RV Wizard · 05-20-2006, 12:08 AM

For those that have a 30 amp service; the main breaker on the coach will protect the power cord from the coach drawing more than 30 amps for an extended time. The problem would be that any loose connections would cause the wiring to be damaged in the cord if the circuit breaker ahead of the cord is greater than the ampere rating of said cord. These circuit breaker are not only designed to trip at a rated ampere but also excessive heat. If the main breaker on the coach fails by not opening at the rated amperes the only next over current protection device is now the 50 amp breaker at the pedastal. I would guess that 90% of the time plugging your 30 amp power cord into a 50 amp receptacle would be fine; it is the other 10% of the time I would be concerned about. I also recommend the use of the "Surge Guard". This protection is worth every penny they charge for them.

Kazoo Tom · 05-20-2006, 07:35 AM

I agree that a surge guard, or other protection device, is a worthwhile investment to protect the entire electrical system in the coach. In fact I intend to make that a future addition, to be hard wired to the electrical access point for the coach. I will be protected from power problems from the campground post, and the generator. In the meantime, I have my screwdrivers and wrenches out to check all the connections, TODAY.