MED posted:First - you need to have a common ground connection between the two ZW-Ls. All the U outputs on the ZW-L are bussed together inside the ZW-L. So you connect a wire from any U of one ZW-L to any U of the other ZW-L. On my layout, I have a bus bar that has about 10 screw connection terminals, and I use this bus bar to create a common ground point - so transformers' U to bus bar, bus bar to track outside rail.
Second, if you are not sure of how your train room is wired back at the circuit breaker box, I would have a power strip that I plug one ZW-L into, then use an extension cord to get from this power strip to the other, distant (from the power strip) ZW-L.
In the more info that you need department - ZW-Ls have a three prong plug for AC, thus the are pre-phased, and leave the manufacturer with the same phasing. You can not reverse the plug, thus you can not change the phasing. By the nature of how the AC power is distributed by the Power Company and your house wiring, you end up with one 110v source that is 180degrees out of phase with the other 110v source. One outlet in you large room could have one 110v source, and another outlet have the 180degree out of phase power. Plugging one ZW-L into one source and a second ZW-L in the 180degree out of phase outlet results in the ZW-Ls being out of phase, and you can only correct the phasing by plugging both ZW-Ls into the same outlet - thus the need of a power strip to an outlet, one ZW-L into the power strip, and the second ZW-L plugged into the power strip via an extension cord.
My ZWL does not have a three prong plug, only two, but does have the polarized plug, one larger than the other. Do they have 3 prong plugs now.
Just curious.
