ATS wiring

[nayther]

bought this and an inverter from Best Converter:

clicky

I'm not clear on how to wire it. I have 50 amp 4 wire service and a 2,000 watt 3 wire inverter. My thinking is the circuit where the inverter lands gets the "jumper" between the two hot legs, then everything else wires as 4 wire. This way only when the inverter is powering everything are they tied together.

The inverter wires to "generator" and then shore power to the next set of contacts, then the left set goes to the main panel.

Should I remove the silver jumpers on the other 2 sets of contacts?

it did not come with a wiring diagram.

[MrWizard]

an ATS switch never switches the ground
grounds in ALL A.C. electrical circuits are Always continuously bonded
Never broken, disconnected or switched

switch the hot side
switch the neutral
Never Ever switch the ground

[shastagary]

i still say there is no reason to switch the ground in fact it can be dangerous.
no other transfer switch instructions i looked at showed switching the ground.
if you have a electrical short to the ground wire it could burn through the transfer switch contacts on the ground wires and leave you with no ground and possible electrocution.
will it work the way you wired it sure till it does not and leaves you with a open ground on your rv.

[nayther]

Well Randy never returned my call or email so I went with my gut.

The wiring diagram above is correct, everything works like a champ. Now once I get my data cable extension (came up about 4' short!) I'll plug it in and we're all set. Now just need to go dry camping!

[nayther]

Ron3rd wrote:
....you could always call Randy at Best Converter.

I'm going to. Sent him an email and he did not respond.

[DrewE]

shastagary wrote:
the ground wires should not ever be switched through the transfer switch.
the ground terminal on your shore cord is extra long it makes the ground connection first when you plug it in you do not want any interruption of that through the transfer switch. all grounds go directly to the silver ground bus only.
i would put a jumper between the aux and neutral connection on the shore input and leave the same jumper on the control panel output that way the now 2 neutral contacts can handle the full 100amps of the shore power cord. 50amps from L1 and 50amps from L2.

Since the two legs are 180 degrees out of phase from shore power, the neutral only carries the differential current, which is never more than a nominal 50A. If both legs are loaded fully, they're balanced and there is no neutral current. This also makes it possible to have 240V loads, though such are quite rare in most RVs.

(The NEC does also permit the two legs to be 120 degrees out of phase, as in two of the three legs of a three phase Y system, but that is very rare in practice for campground power systems and as the differential currents still partly offset so the maximum neutral current is still 50A. A range outlet in an apartment complex would be more likely to be on a three-phase system and so have this setup.)

The time when you'd see more than 50A on the neutral is with some RV generators (ones larger than 6 kVA) that are set up for 120V operation with two parallel breakers feeding the two legs.

[Ron3rd]

....you could always call Randy at Best Converter.

[shastagary]

the ground wires should not ever be switched through the transfer switch.
the ground terminal on your shore cord is extra long it makes the ground connection first when you plug it in you do not want any interruption of that through the transfer switch. all grounds go directly to the silver ground bus only.
i would put a jumper between the aux and neutral connection on the shore input and leave the same jumper on the control panel output that way the now 2 neutral contacts can handle the full 100amps of the shore power cord. 50amps from L1 and 50amps from L2.

[nayther]

This is what I come up with, see anything wrong. I think i just need to remove the one jumper.

I know I'll have to turn off the converter when I'm using the inverter to open the loop.

[shastagary]

the ground wires (green) from the power cord and back to the breaker panel go to the silver terminal strip on the bottom they do not get switched through the transfer switch.

[shastagary]

the silver jumpers are there to give it 2 relay contacts on the neutral connection so it can handle the full current of the inputs.

[DrewE]

The two hot legs from the inverter would get jumpered together assuming you want both legs powered by the inverter. If you can have all the circuits you want to have inverter power for on one leg and all the ones you don't want powered by the inverter on the other (such as the converter, water heater electric element, fridge if two-way) and have no 240V loads in the RV, then you can power just the one leg and leave the other disconnected (or tie it to neutral, I suppose).

The neutral to ground bond (the jumper) should definitely be removed from the output terminals. It maybe should be removed from the inverter input terminal, as well, depending on how the inverter is wired and what the maker recommends. If the inverter bonds neutral and ground for its output internally, then that jumper should be removed; likewise if it's an oddball one where tying neutral to chassis ground would cause it to let out the magic smoke.

Note that you will have a 30 second time delay when switching over to inverter power. Clocks etc. will reset themselves.

IMPORTANT EDIT: Disregard what I said about connecting the ground (now in gray type above). The ground indeed should not be switched; likewise, the jumpers remain in place and are both connected to the neutral line. I was not thinking straight when I wrote that paragraph. Mea culpa.