does it matter of the power

[chad tm5000/trainstation]

does it matter the power if your running tmcc or other cordless remote. meaning a zw or t-4000 from mth on a 12x22 layout with bus lines and how thick should the primary wire be for a bus line  and how far a part going down the track should the connections be. i was thinking 3ft appart

[lionelsoni]

Wires should always be heavy enough to carry safely the maximum current that your supply (transformer) can put out.  This maximum current is usually the rating of the circuit breaker or other overcurrent protection.  Use at least 10 AWG for 30 amperes, 12 for 20, 14 for 15, 16 for 10, 18 for 7, 20 for 5.

[traindood]

hello: most of us homeowners have 15 or 20 amp circuit breakers. unless you want to use extra heavy wire, 12ga. wire is ok for most bus lines. keep in mind however, some people can get carried away with lights,accessories etc. in that event, you would have to split your power demands with two or more circuit breakers. i use 18ga. for feeders and 22or 24ga for my dz2500 switch machines. my layout is only 15 x12 so it works for me. longer runs would require heavier ga. for switches, but not for bus lines or feeders i solder my gargraves track  every 3 feet or so, however, i solder both sides of outside rails for ground as well as center rail for power. yea, i know overkill, but that's the kind of hairpin i am! later.          

[lionelsoni]

The rating of a house's branch circuits implies little about the overcurrent protection that a train transformer might need.  For example, a perfectly efficient transformer supplied by a 20-ampere branch circuit could put out as much as 160 amperes at 15 volts before it tripped the 20-ampere 120-volt breaker.  The reason is that, as the transformer reduces the voltage, it increases the current.

It would take a very large layout indeed to need more power than a single 15-ampere 120-volt branch circuit can supply.  Assuming that the transformer(s) draw no more than the allowed 80-percent of the circuit rating (that is, 12 amperes), that the transformer efficiency is about 75 percent, and that the secondary voltage is 15 volts, the layout would have 72 amperes available.  That's a lot of trains.

Eighteen AWG is heavy enough for a 7-ampere transformer, something like an LW or a V, but is not safe for a KW, Z, or ZW.