Shore Power Problem

[kmuller]

I pulled into my barn, unplugged a Monaco from the 50amp, plugged the Liberty in from the shore power reel and 50' of 30 amp extension cord and the wires in the barn started humming and vibrating (loud)! The 50 amp breaker did not trip, and I unplugged in a second or so. Tried the port and starboard plug ins via the Marineco cord and....same thing. Ran a 15 amp line from a regular socket via adapters to the power reel and Marineco's and immediately popped the GFI on the barn.

I cut the shore power switch on the bus....same thing. When I fire up the generator, all is well, the bus likes the 110 coming from genset. My residential electrician says all is well with the barn plug.

I plugged the Monaco back in and all is well there. Must be something in the coach. Any ideas out there?

Thanks.

[garyde]

The Vibrating and humming of wires and breakers indicates a heavy current in rush. Check to see what breakers are on in your Liberty. I would shut down all of the 120/240 volt breakers in the Liberty and then plug in. If you still have a problem, it sounds like a direct short. If not , try turning on your Inverter chargers 1st in your breaker panel.

[kmuller]

Gary - I have everything shut down...all coach breakers, inverter panel, inverters, and shore power breaker. Plug in and the barn wires humm, but do not trip the barn breaker.

Karl

[Jon Wehrenberg]

Karl,

I have not had a problem in this area so I can't give you detail, but if I were to guess the issue is in your big gray box on the driver's side, on the rear bulkhead of the first bay. I think there are relays in there that close when you have shore power or generator power.

If I were to guess the noise you hear is the coil trying to pull the contactors on the relay, but failing.

You will trip a GFCI on a power outlet when you try to hook up the coach. If you have a 30 amp outlet in you power box try that one.

Before you tear your coach apart, or call Liberty, test to make sure you have power on both legs of your 50 amp receptacle. Let us know because there are a lot of us Liberty owners that could have the same problem.

[kmuller]

Jon - thanks for the feedback. I will let you know what we find.

[MangoMike]

Karl,

Jon has jogged my memory on this issue. Maybe the same or not.

In that grey box there is a relay that switches the system over from shore to gen or bus battery. Mine didn't hum but I kept on hearing a clicking when I plugged in the shore power, with a lot of pulses. There is two relays (one for shore and one for the generator) that switch the system over with I believe a dial on the top of each one that sets the delay. One of my two had gone bad and after talking to Liberty I just switched the two - they just pull out, until they sent me a replacement. I'm not a the bus now or I would get you better detail.

By the way, never congratulated you on your new Liberty. We need to see some pixs.

Mike

[kmuller]

Mike - thanks for that imput. I do have a spare relay and will try it tomorrow. The hummmmmm is coming from the conduit in the barn running between the breaker box and the 50 amp receptacle. It may be making a noise at the coach as well, but since I was standing at the barn recepticle, I don't know what is going on at the coach. I'll let you know what I find/figuire out.

Keep the ideas coming!

[garyde]

Gary - I have everything shut down...all coach breakers, inverter panel, inverters, and shore power breaker. Plug in and the barn wires humm, but do not trip the barn breaker.

Karl

Well, it sounds like a short then. Try the 30 amp aux cord connection, and switch that grey box to 30 amp and see what happens. If you have no significant load and you are still getting the noise, it must have something to do with the 50 amp cord to the grey box which is your transfer switch.

[truk4u]

Karl,
Are you saying the barn has a 50 amp receptacle and you plugged in 50' of 30amp cord (with an adapter I'm sure) and then plugged that into your 50 amp reel? If this is correct and your reel is 25', you then have a total of 75' of cable, part 30 amp and the other 50 amp.:confused:

[kmuller]

Tom - I have tried about every combination, but what I am primarily working with is the starboard Marinco outlet (3 prong/50amp), a 20' length of 30 amp cord with Marinco female plug (that plugs into the coach), then my 50' of 30 amp cord with adapter that plugs into the 50 amp barn receptacle.

So basically it is 70' of 30 amp cord, plug into the coach on one end, and thru an adapter to a 50 amp plug on the barn.

[kmuller]

Looks like we figuired it out. This morning I pulled the coach right up to the barn, plugged the 50 amp reel in and ....worked great. Unplugged the 50 and tried the 30 amp Marinco...worked great. There appears to be a voltage drop in the 50' of 30 amp extension I was using. Either in the cord itself, or the plug ends (most likely source). The lower voltage was not allowing the transfer switches to pull in hard, they were just sitting there chattering. The transfer switches on the liberty are pretty beefy and evidently very voltage sensitive.

As one of our marine tech's said, the coach doesn't know how long the cord is, only what the voltage is or isn't. This could happen regardless of what cord you are using if the wires were damaged or plug ends not up to snuff. With 5, 10, 15, 20 year old plugs and cords out there, it would be good to check them frequently for voltage drop.

[garyde]

Looks like we figuired it out. This morning I pulled the coach right up to the barn, plugged the 50 amp reel in and ....worked great. Unplugged the 50 and tried the 30 amp Marinco...worked great. There appears to be a voltage drop in the 50' of 30 amp extension I was using. Either in the cord itself, or the plug ends (most likely source). The lower voltage was not allowing the transfer switches to pull in hard, they were just sitting there chattering. The transfer switches on the liberty are pretty beefy and evidently very voltage sensitive.

As one of our marine tech's said, the coach doesn't know how long the cord is, only what the voltage is or isn't. This could happen regardless of what cord you are using if the wires were damaged or plug ends not up to snuff. With 5, 10, 15, 20 year old plugs and cords out there, it would be good to check them frequently for voltage drop.

Good News. Voltage Drop can be hazardous to your Coaches Health.. 3% Voltage drop is all you want to allow. Make sure to have a digital volt meter with you if you have similar problems in the future. Low Voltage and High Voltage can damage electronic components in your Coach so You are lucky the transfer switch did not switch in.... Also, did I hear you say you had plugged a 50 amp Cord into a 30 Amp Cord? You must keep the same size wire all the way to the Recepticle. 50 amp= # 6awg, 30amp= #10 awg wire. Gary