Automatic Transfer Switch testing

[Cate&Rob]

I don't have an ATS, but would I be correct thinking it is a 3 pole contactor switching two hot legs and the neutral?

I also don’t have an ATS, but my boat had an MTS (manual transfer switch) which was a 4 pole transfer. L1, L2, N & G. The neutral is a current carrying wire and neutral and ground should only come together at the source of the electricity. (This may have been complicated on the boat by the ground also going to the water only when away from the dock)

Rob

[ncitro]

The only one I’m familiar with is the Progressive Industries, it switches the hots and neutral but not the ground. The grounds are all tied together.

[ajg617]

Confirmed with GD that a few RVs had Magnum Inverters installed (ours included) which have their own ATS. Now I'm wondering if the Inverter (which I did not have turned off) was what actually tripped the house CB and is providing the 5-7 volts at the 50Amp lugs on the exterior receptacle. I'll run the next test with inverter and shore off and generator on and see if I have any voltage at the lugs. But a review of all the wiring is in order. In any case, it is something I will mention during our factory visit.

[ncitro]

We are getting into my best guess here, but I believe that when there is an inverter with a built in transfer switch, that there is still an external transfer switch for the generator. In effect having two transfer switches. This would complicate the wiring and point even more to you tracing the wiring and seeing what you have an tracing it all out as Scott suggests.

That said Inverters sometimes do cause GFCI outlets to trip, my old Multiplus type 1 had this issue, but the newer type 2 does not.

[ajg617]

We are getting into my best guess here, but I believe that when there is an inverter with a built in transfer switch, that there is still an external transfer switch for the generator. In effect having two transfer switches. This would complicate the wiring and point even more to you tracing the wiring and seeing what you have an tracing it all out as Scott suggests.

That said Inverters sometimes do cause GFCI outlets to trip, my old Multiplus type 1 had this issue, but the newer type 2 does not.

I'm getting to appreciate the complicated wiring aspect. I have two ATS it appears - one for shore and one for solar not to mention what may be on the generator. FYI, the CB and GFCI that tripped were in my house.

[acoleman43]

I'm getting to appreciate the complicated wiring aspect. I have two ATS it appears - one for shore and one for solar not to mention what may be on the generator. FYI, the CB and GFCI that tripped were in my house.

Inverter wiring could be involved. If I were you I would make sure all components are wired correctly. For example, each power source uses just 1 neutral. If you have a neutral from shore power and the neutral from the generator wired together, it will trip the breaker in your house (if you are connected to home shore power). All neutrals must be separated for each power source (they cannot be wired to the same bus bar).

I hope that makes sense.

[ncitro]

I'm getting to appreciate the complicated wiring aspect. I have two ATS it appears - one for shore and one for solar not to mention what may be on the generator. FYI, the CB and GFCI that tripped were in my house.

Keep in mind its not solar (thats 12v and unrelated). One transfer switch is between shore and generator, and then one is the output of that transfer switch and the inverter.

I agree with Allen verify correct wiring. Incorrectly bonded/applied neutrals could definitely be causing the GFI in the house to trip.

[ajg617]

Keep in mind its not solar (thats 12v and unrelated). One transfer switch is between shore and generator, and then one is the output of that transfer switch and the inverter.

I agree with Allen verify correct wiring. Incorrectly bonded/applied neutrals could definitely be causing the GFI in the house to trip.

Correct not solar - my mistake. Two separate transfer switches - one WFCO and one Magnum off of the Inverter. Two AC inputs to the Magnum which I'm curious about. I'll be tracing cables for a bit.

[ncitro]

The two inputs on the magnum should be the inverter (I think that’s the top on your picture) and input 2 will be the output of the other transfer switch.

[TedS]

The inverter ATS should be on the load side of the generator/shore power ATS. It switches from pass-through ac to inverter generated ac for its load.

[Scott'n'Wendy]

I also don’t have an ATS, but my boat had an MTS (manual transfer switch) which was a 4 pole transfer. L1, L2, N & G. The neutral is a current carrying wire and neutral and ground should only come together at the source of the electricity. (This may have been complicated on the boat by the ground also going to the water only when away from the dock)

Rob

I have never come across a situation where ground was switched. Only continuous. I have no marine experience though. At first thought, I don't think I like the idea though. Ground always needs to be good solid ground for when the warm brown stuff hits the fan. But ya, I can see boats being a special case.

[Cate&Rob]

I have never come across a situation where ground was switched. Only continuous. I have no marine experience though. At first thought, I don't think I like the idea though. Ground always needs to be good solid ground for when the warm brown stuff hits the fan. But ya, I can see boats being a special case.

Hi Scott,

You are right . . . I should not have thrown the marine situation into this discussion. It is about galvanic corrosion between adjacent boats enabled by shorepower electrical ground wires completing the galvanic circuit between hulls. Nothing to do with RVs.

Rob

[Jlawles2]

I'm going to make an observation guess from the outside here. ATS stands for Automatic Transfer Switch, which means it has 2 inputs and 1 output, follow me?

The WFCO one may have internal feeds that you do not see, hence not seeing 2 wires. I'm going to guess it's one feed from the external grid feed and the other from the Generator.

The Black Magnum one is feeding select components and is being fed from the WFCO box by one input and the inverter from the other (it kinda says this on the outside markings).

What could have happened to trip your home CB especially if it's GFCI is the imbalance between the hot an neutral legs during the transfer of power from the generator or even if the generator has a self bonding relay that engaged which will cause an imbalance in the hot - neutral amps tripped the GFCI.

[acoleman43]

I'm going to make an observation guess from the outside here. ATS stands for Automatic Transfer Switch, which means it has 2 inputs and 1 output, follow me?

The WFCO one may have internal feeds that you do not see, hence not seeing 2 wires. I'm going to guess it's one feed from the external grid feed and the other from the Generator.

The Black Magnum one is feeding select components and is being fed from the WFCO box by one input and the inverter from the other (it kinda says this on the outside markings).

What could have happened to trip your home CB especially if it's GFCI is the imbalance between the hot an neutral legs during the transfer of power from the generator or even if the generator has a self bonding relay that engaged which will cause an imbalance in the hot - neutral amps tripped the GFCI.

That's what I'm thinking. I would look in the WFCO ATS box to make sure shore and generator are completely separated. If there is an imbalance between hot and neutral, the GFCI will trip. If both neutrals are connected, there will be an imbalance and trip the GFCI circuit.

[ajg617]

I'm going to make an observation guess from the outside here. ATS stands for Automatic Transfer Switch, which means it has 2 inputs and 1 output, follow me?

The WFCO one may have internal feeds that you do not see, hence not seeing 2 wires. I'm going to guess it's one feed from the external grid feed and the other from the Generator.

The Black Magnum one is feeding select components and is being fed from the WFCO box by one input and the inverter from the other (it kinda says this on the outside markings).

What could have happened to trip your home CB especially if it's GFCI is the imbalance between the hot an neutral legs during the transfer of power from the generator or even if the generator has a self bonding relay that engaged which will cause an imbalance in the hot - neutral amps tripped the GFCI.

The AC Input 1 (Inverter) feed plugs into the GFCI on the end of the inverter - I do know that when that GFCI pops, I have no AC power at any other 120V outlets. The 4/0 cable on the opposite end of the inverter runs to the inverter disconnect switch and then down to the batteries with a large Magnum fuse in between. The Utility and load cables run to fuse blocks with yellow romex coming out the other end.and into a metal shielded tube. Haven't found the other end of the yellow romex lines yet but they could very well be headed to the pass thru area - I just can't see them yet. The WFCO has three shielded bundles of cable - one going to the fuse panel and two going into the underbelly on each side of the coach but heading towards the rear. More to come.