Continued Generator Issues...

[nothermark]

Originally Posted by A Traveler

No, that's not how electricity works. A loose, high-resistance connection will not cause a breaker to trip.

RESISTANCE in an electrical circuit RESISTS the flow of current, thus REDUCING the current flow through the circuit. The amps drawn will go down, not up.

On the other hand, a loose wire bouncing around as the coach moves down the road could touch something it shouldn't and cause a momentary short circuit which WOULD trip the breaker.

It is how it works. We are talking low resistance making heat that warms up the thermally operated breaker. Heat is Current squared times Resistance. Calculate the heat produced by a quarter ohm of contact resistance vs the voltage drop and you will get the picture.

For example, assume 2/3 of rated current. A 30 A breaker and 1/4 ohm resistance 20 A produces 100 W of power with a 5 V drop. Lot of heat but not enough resistance to cause circuit problems so the load will still draw 20 A with or without the contact resistance.

[Josh2129]

Another line of thought here, I had a similar problem with an Entegra coach. Generator run fine sitting still but when I got on the road it would randomly trip the main breaker on the generator. Finally found that the chassis air condition condensation line was crimped and the condensation was pouring out on the generator and the electrical connection. Repaired the condensation line and the breaker tripping stopped. Just thought i would toss that out there.

[OLYLEN]

Thing that does not ring true is, if the load to the two 30 amps are switched the other breaker should now be the problem. If the same breaker still blows change the breaker itself.

LEN

[twinboat]

Originally Posted by nothermark

It is how it works. We are talking low resistance making heat that warms up the thermally operated breaker. Heat is Current squared times Resistance. Calculate the heat produced by a quarter ohm of contact resistance vs the voltage drop and you will get the picture.

For example, assume 2/3 of rated current. A 30 A breaker and 1/4 ohm resistance 20 A produces 100 W of power with a 5 V drop. Lot of heat but not enough resistance to cause circuit problems so the load will still draw 20 A with or without the contact resistance.

Your example will hold true if the loose connection is at or very near the breaker, but how would the resistance and heat effect it 6 feet down the wire ?

A bad connection would be like adding a resistor, in series, to the circuit. There would be a voltage drop, due to it, but the amps wouldn't climb.

[Soppy]

Try turning off all the breakers at the distribution panel , then starting the generator and go for a drive. If the breaker trips , you got a short between the generator and distribution panel . If it doesn't trip turn on half the breakers and go for another drive.Keep switching on & off breakers till the generator breaker does not trip. You should be able to isolate the problem that way.
If the breakers were wired wrong , they would trip when you are stationary.

[manderson2228]

Originally Posted by ThePowells

Where are you at in NC?

I am not I am in Atlanta.

[A Traveler]

Originally Posted by nothermark

It is how it works. We are talking low resistance making heat that warms up the thermally operated breaker...

Sigh...

No, this is NOT how electricity works. I know...I have worked with electronic and power circuitry all my adult life.

Your heat example is only true if the high resistance (and heat-producing) connection is ON the breaker itself. A high resistance connection anywhere else will also generate heat, but the breaker won't feel it. That high-resistance connection will resist the flow of current, thus lowering the number of amps drawn.

Google "Ohm's Law."

[triplewide]

Originally Posted by Soppy

Try turning off all the breakers at the distribution panel , then starting the generator and go for a drive. If the breaker trips , you got a short between the generator and distribution panel . If it doesn't trip turn on half the breakers and go for another drive.Keep switching on & off breakers till the generator breaker does not trip. You should be able to isolate the problem that way.
If the breakers were wired wrong , they would trip when you are stationary.

x 2

[nothermark]

Originally Posted by twinboat

Your example will hold true if the loose connection is at or very near the breaker, but how would the resistance and heat effect it 6 feet down the wire ?

A bad connection would be like adding a resistor, in series, to the circuit. There would be a voltage drop, due to it, but the amps wouldn't climb.

Then the wire insulation changes color and things start to melt. Typical if the connection is to the transfer switch or some other connection point.

[Quincy]

I did not read all the replies so I am not certain if this has been suggested. I believe you have a loose ground wire somewhere. Loose grounds can cause all sort of problems that dont seem related and the constant on and off of the items on that circuit can cause the breaker to trip if an increase in amps is required to start the device. It may be hard to find because it dosent have to be loose enough to "wiggle". Electrical connections that are say, finger tight, will get a coating on them that will insulate the contact until it is moved and removes that coating.

Good luck and keep me us posted.

Q

[aether_one]

Originally Posted by nothermark

It is how it works. We are talking low resistance making heat that warms up the thermally operated breaker. Heat is Current squared times Resistance. Calculate the heat produced by a quarter ohm of contact resistance vs the voltage drop and you will get the picture.

For example, assume 2/3 of rated current. A 30 A breaker and 1/4 ohm resistance 20 A produces 100 W of power with a 5 V drop. Lot of heat but not enough resistance to cause circuit problems so the load will still draw 20 A with or without the contact resistance.

Originally Posted by A Traveler

Sigh...

No, this is NOT how electricity works. I know...I have worked with electronic and power circuitry all my adult life.

Your heat example is only true if the high resistance (and heat-producing) connection is ON the breaker itself. A high resistance connection anywhere else will also generate heat, but the breaker won't feel it. That high-resistance connection will resist the flow of current, thus lowering the number of amps drawn.

Google "Ohm's Law."

Internet Fight!!!

Yes the heat generated by the resistance of a bad connection robs power from the circuit, but that heat will NOT trip the breaker.

Yes the added resistance in a resistive only circuit will lower current flow.

But we are talking about a dynamic, non-resistive circuit when talking about an air conditioner.

The air conditioner has a load of 15k BTU, we'll call it 1800 watts.

At 120 VAC we need 15 Amps to handle that load.

If we add our "resistor" in series in the circuit creating a voltage drop so that the air conditioner only sees 100 VAC then it will require 18 Amps to do the same cooling work.

So yeah, in a case like this a poor, high resistive connection can cause current to increase in the circuit it would not be enough to trip the breaker due to overcurrent. In most cases the high resistance connection would burn open or the air conditioner would shut down on low voltage before the breaker trips.

[manderson2228]

I went out this morning and did some poking around. We are currently at Fort Wilderness on vacation so I can't do a ton of work on this right now.

First I found a junction box, you will see in the picture. A ground for the box itself is down on the right hand side of the box. You can also see that either from the factory or after the fact someone electrical taped everything around the wire nuts.

Someone I believe "Quincy" mentioned ground, and I didn't read his post until after i went out but oddly the ground on the transfer switch A (Furrion F50-ATS) You can see in one of the pics it's bolted to the frame but I was also taught so get the paint off from behind the ground so it makes a better connection. This is main ground to the ground bar. Again it works fine stationery, and on shore power so this if an issue I would think would produce other issues at other times if it was a problem.

Last i took a picture of the transfer switch. As you can see nothing sticks out in terms of raw wire that might be hitting something while moving.

This still leaves the cabling behind the Generator as a possible culprit but I couldn't easily get to it this morning to check. The mystery continues.

[Quincy]

I studied the pictures you posted and would respectfully suggest you get a square tipped driver and tighten all of the lugs on the busses including the ground buss on the right. Since the RV is a floating ground the ground and common are the same and all would be suspect if it were me.

Q

[twinboat]

In picture 3 on the right side, is that tan romex cable or cooked romex cable, leaving the metal box ?

Could just be the lighting from the picture.