Household Power Requirements for Postwar Lionel Transformers

[Dougaz]

I am starting to recreate a postwar Lionel layout I built about 20 years ago This time for my son and grandson. It will be powered by two ZW's and a Z for powering the switches and accessories. There will be three mainlines, 25-022 switches, and about ten accessories operated mostly one at a time. 20 years ago I plugged the three transformers into a surge protector and then into an outlet in a large second family room with not much else plugged into that rooms circuit. It worked fine and I never tripped a breaker. This time I am perhaps a little more cautious about how much power I need to run these three transformers. I am no electrician but I think most circuits for lights and outlets are 15 amps. My question is about how many amps are these three transformers going to draw and do I need to run a dedicated circuit?

[smokey1]

I'm sure they're better folks to answer this than myself, but since no one has posted here are my thoughts, You say you're running three loops ( I'm guessing isolated from each other ) Okay ZW #1 powers first two loops, ZW #2 one side powers the third loop, why don't you run your switches off of the other side. Then you can eliminate the Z transformer. And have it as an emergency back up. 

[BigAl 956]

Speaking from experience I ran a large layout with 3 ZWs, up to 5 PW trains running at a time. The whole thing was connected to a standard 15a outlet with the rest of the basement wired into the same circuit. I never popped the breaker in the 15+ years I lived there.

Earth ground is more important if you are running a control system. I had trouble with TMCC operations. I tested the outlet with a simple tester and found the earth prong was open. Turned out the outlet was rusted from a previous basement flood. I replaced the outlet and added a battery sump pump. 

[ADCX Rob]

Dougaz

My question is about how many amps are these three transformers going to draw...

Less than 7 amps, at full load, on every one.

Dougaz

...do I need to run a dedicated circuit?

No.

[Flintlock76]

Good advice from the other posters!  

Just make sure your electrical outlet doesn't look like this guys...

https://www.youtube.com/watch?v=JGnUexrYlwY  

And  aboard!

[pennytrains]

to the fun train!

Becky

[lionelsoni]

The nameplate of the ZW-R says that it needs 275 watts at 115 volts, which works out to be 2.4 amperes.  The Z has no nameplate, but it's very similar; so thats 7.2 amperes for all three together.  Branch circuits are protected at either 15 or 20 amperes, but any one appliance may draw only 80 percent.  A 7.2 ampere load is well under that, assuming the worst-case 15-ampere circuit.

Keep in mind that receptacles can have either of two phases, 180 degrees apart.  This is particularly likely with duplex receptacles, which often are wired to two out-of-phase branch circuits with a common neutral wire.  If you're counting on any particular phase relationship among your transformer outputs, it's a good idea to combine all the transformer plugs onto a strip like you did before.

[Banks]

lionelsoni

Branch circuits are protected at either 15 or 20 amperes, but any one appliance may draw only 80 percent.

 

Keep in mind that receptacles can have either of two phases, 180 degrees apart.  This is particularly likely with duplex receptacles, which often are wired to two out-of-phase branch circuits with a common neutral wire.  If you're counting on any particular phase relationship among your transformer outputs, it's a good idea to combine all the transformer plugs onto a strip like you did before.

Total continuous load  from ALL connected loads cannot exceed 80% of the rated current.

 

Possible but very unusual for a duplex to have more  than one circuit connected.  In 40+ years in the trade I never ran into that.

[lionelsoni]

My copy of the NEC is woefully out of date, but my 2008 NEC says in 210.23(A)(1), "The rating of any one cord-and-plug-connected utilization equipment not fastened in place shall not exceed 80 percent of the branch-circuit ampere rating."

I don't have any in my house, but I have seen multiwire branch circuits, always with one circuit switched, for plug-in lamps in rooms without any ceiling or other general lighting.  Each duplex is split to allow plugging into either circuit.

Building-code differences between countries fascinate me.  Although US and Canadian practices look very similar, multiwire branch circuits are an interesting example of the more conservative Canadian approach:  They require that the neutral of a split duplex be pigtailed to the neutral wires in and out of the box, so that disconnecting the neutral from the duplex doesn't interrupt the neutral to downstream loads.