What could cause low AC voltage on only one side, main 2 ??


FTL_Alan

FTL_Alan

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Noticed today that I get normal AC voltage on Main 1 (meter reads about 120), but only getting about 30 AC volts on Main 2. This is before I put any load on either circuit. When I put a load on Main 1, all works fine, but trying to put any load on Main 2 causes the meter to go to zero. What could cause this? Fuses look normal.
 
Are you using two shot power cords? If so I would check the connection on the bad side both at the boat and the dock.
I had a wire become loose on the back of the boats plug where the shore power plugs into. I burnt two different shore power cords plugging into it before taking the plug apart and finding the insides of the plug burnt.
 
Take a volt meter and check the voltage right at the meter connections. You may find that the meter is not reading correctly.
 
I should have clarified, this issue is when I'm running the generator. Shore power works fine. I am disconnecting the shore power, turning off both shore power breakers (main 1, main 2), and then starting the generator and transferring the power at the electrical panel. When transferring power and looking at the volt meter on the panel gauges, I see normal (i.e. 115-120) AC voltage level on main 1, but the voltage level on main 2 is only about 30 volts. Photo below was taken just after transferring power and all AC breakers on the panel were off. When I turn on the AC switches on main 1, all is normal and all circuits are working. When I try to turn on any of the main 2 AC switches, the meter goes to zero.

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Shore power is normal on both and not on gen? Need to know what you have for transfer switches. There’s a two leg breaker on the gen panel at the gen as well. Sounds like a loose connection. Be careful with live connections 120 ac can give a pretty good jolt. Worse case 1 leg in gen not working correctly.
 
Here's a pic of my elect panel. Agree this may be a loose connection, because I did another test this morning. This time, main 2 showed normal voltage when I flipped the transfer switch, which is different than what happened yesterday, where main 2 showed low voltage when I flipped the transfer switch. So when I saw normal voltage today after flipping the transfer switch, I continued to test main 2 circuit by turning on the breakers on that circuit. First, turned on water heater breaker, meter showed normal voltage. Next turned on Ice Maker breaker, still at normal voltage. Next turned on Stove breaker and turned the burner on high.. this time I saw the meter dip a little and then return to normal voltage. Lastly I turned on the TV breaker, and at that breaker the meter went to zero and the stove burner shut off. I then switched all the breakers off and switched off the transfer. I wanted a few seconds and switched the transfer back on and noticed that the meter now showed low voltage again, just like the photo in my first post above, where the meter is at the 30 mark.

I opened the panels to check for loose connections. All looked normal.

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I agree with Evermore, sounds like a loose connection. Working from memory here, When on generator Main 1 is switched to Generator, that feeds the Main 1 circuits, Main 2 is then switched to Transfer which applies power to the Main 2 circuits. That being said, an easy test might be to leave on shore power, (Generator Off) turn on Main 1, then transfer Main 2, see if you get the same results, if so, there is a loose connection on the transfer breaker.
Without the schematics in front of me this is all from memory. Boat is sleeping for the winter, it uses the manuals as a pillow. :>)
If you don't get this sorted out, next time I'm down, I'll take a look.
 
The beauty of our Formulas is their systems design. GrandDFreehold is correct. Shore power on shore 1, turn off shore 2, turn off the breakers on individual items on 1, leave main 1 on, slide blocker across, turn on 2 as if it were on the generator, then turn on the circuits on 2 one at a time as you did before. This will test the circuits from the panel after the #1 main and the breaker for the second circuit from the panel through the boat. The reason to turn off the individual breakers to 1 is you will only be able to use 30 amps total with both circuits. We have used this setup when marinas have had limited power. It's part of the design of the breaker panel and is shown in the manuals.
 
FTL_Alan said:
Here's a pic of my elect panel. Agree this may be a loose connection, because I did another test this morning. This time, main 2 showed normal voltage when I flipped the transfer switch, which is different than what happened yesterday, where main 2 showed low voltage when I flipped the transfer switch. So when I saw normal voltage today after flipping the transfer switch, I continued to test main 2 circuit by turning on the breakers on that circuit. First, turned on water heater breaker, meter showed normal voltage. Next turned on Ice Maker breaker, still at normal voltage. Next turned on Stove breaker and turned the burner on high.. this time I saw the meter dip a little and then return to normal voltage. Lastly I turned on the TV breaker, and at that breaker the meter went to zero and the stove burner shut off. I then switched all the breakers off and switched off the transfer. I wanted a few seconds and switched the transfer back on and noticed that the meter now showed low voltage again, just like the photo in my first post above, where the meter is at the 30 mark.

I opened the panels to check for loose connections. All looked normal.

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Do you think you could be drawing more amps than the genny can deliver?
 
Thanks for the suggestion to test main 2 using the transfer switch while on shore power, I would have never thought of that.. and it led me to finally solving this issue (I think). Following instructions from GranDFreehold and Evermore, I connected shore power, leaving main 2 breaker off, went to the panel, flipped on main 1 breaker but left all of the individual main 1 switches off, voltage was good as expected.. then I slid the metal cover on top of main 2 shore power and flipped on the transfer switch and noticed normal voltage on the meter, i.e. 120-130 volts.. so I then turned on all of the individual switches on main 2 and everything worked... So, that told me I did not have any issue at the panel. Here's the likely cause: when I was running the gen for all of these tests, I was using the hose connection. Prior to this issue, I've only used the hose connection to flush the gen for a couple of mins, then turn off the gen. What was different, was that I had changed the gen oil and wanted to run the gen for 10-15 mins to get it up to normal operating temperature so that I could check the oil level after running it at operating temp. During this 10-15 mins, that's when I tried to load the gen and that is where I noticed the low voltage issue. So, after confirming I had no loose connections using the test using shore power to isloate main 2, I then dropped the boat in the water and ran the gen using the water pump. This time, I had no issue at all on main 2. So, that tells me that my problem was due to running the gen on the hose connection. Even though I was getting good water flow, there is something about the hose connection that is not ideal for putting a load on the gen, causing it to have low voltage on main 2.
 
I'm really not sure that should have solved your problem, but I hope it did. Anyone else please chime in. If it occurs again there has to be a connection from Shore 1 to Gen 2 breakers and gen1 to gen 2. I've never specifically looked at the panel wiring for this exact circuit but there has to be a jumper from main 1 to gen 2. With that said I don't know if there are two leads from the gen to both gen breakers or another jumper. With the way the panel operates and the blocking of switches for shore and gen it's possible to have these switch combinations and still keep everything isolated. Somebody had their S**t together to think this up. Anyway if anything further crops up will try to help.
 
Yep Evermore, you must be right in concluding "there has to be a jumper from main 1 to gen 2", because I was able to turn OFF the main 2 shorepower breaker (under the starboard bench seat on a 350-SS) and then use the Gen Transfer switch to power the Main 2 circuit. So that Transfer switch does 2 things: 1) used to power up Main 2 AC when running on the generator, and 2) transfers Main 1 power to Main 2 when running off shore power using only the Main 1 breaker. Also to note, my mechanic scolded me for using the gen flush port for anything other than quickly flushing the gen. He said the water flow coming from the hose is not sufficient to put any load on the gen. The flush port is only for running the gen a minute or two to quickly flush the system, then turn it off. At least, prior to this episode, I haven't been using the hose to run the gen with a load, just to do a minute or two of flushing after each run out on the ocean or on the intracoastal in brackish water.
 
Keep your mechanic, others would not have said anything and just let you go. Having a professional give advice is how it should be. My compliments to your technician.
 
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