Just got my layout pretty much done. Just have to add 2 more pairs of switches and add some more engines and cars. But, I have almost 3,000 feet of wiring and 6 transformers. Its been tough, but I am through most of it. I am going to take some pics and show them to my local hobby shop. Hardest thing about making a layout, has to be the wiring. It gets so confusing remembering how these accessories wire up. My diagrams do help alot. Also, color coded wiring and terminal strips are helpful. Now, I have a question. Plugging in multiple transformers on a power strip then plugging that into one socket. Do all transformers get full power? or does the one farest down the line on power strip see less power?? Should I try using 2 power strips?? Thanks.
I seriously doubt you would ever see any difference in power output on the power strip. The wiring in the power strip is more then adequate for the amps in your house circuit (probably 15 or 30 amps). So if you don’t pop your home circuit breaker, you should have no trouble.
Earl
Well, I have a 15 amp service in my basement. Should upgrade. But, when I have 3 transformers and all dials on full blast then when I try to trottle the 4th transformers the power in that 4th transformer dies. But, then again I never have more then 1 transformer on full blast at one time. I am only skilled enough to run 1 loco at a time, and have all my switches powered. Maybe 2 locos at time. It just too risky for me to run more than 2 locos at a time. Just so much to keep an eye on. With kids wanting to touch everything, you know what i mean. I tried getting 2 power strips. No difference. Oh well. Now, wiring. My wiring says it can with hold up to 48 volts. Now, my transformers can go up to 24 volts. There is no way to melt this wiring?? It is 16 AWG and some bigger than that. I was told 16 AWG is good enough. 20 AWG would be the minimum. I use solid strand. I have never had a melted wire in my 20 years of model railroading. I believe wiring is key to a nice performing layout, power wise. thanks.
Sixteen AWG is not good enough. The Z and ZW can put out 15 amperes; so use a minimum of 14 AWG. The KW puts out 10 amperes, so use at least 16 AWG for it. If you have a single-wire return that is common to multiple transformers, add the individual transformers’ current ratings and use a wire that can handle the total, for example 12 AWG for 20 amperes, 10 AWG for 30 amperes, 8 AWG for 40 amperes, etc, doubling every 4 AWG sizes.
Your 15-ampere 120-volt primary circuit should be able to handle transformers totaling some 100 amperes of secondary current, more than you have unless you have lots of transformers. I doubt that the primary circuit has anything to do with your fourth transformer’s problem. If you’re using a single 16 AWG return, that might explain something.
Whatever “solid strand” is, it doesn’t matter at all electrically whether you use solid or stranded wire. The voltage rating of the wire has nothing to do with how much current it can carry.
Using 16 AWG seems to work okay. What would be the difference if I were to put in 14 AWG?? Any power difference?? More power? Brighter lights? I have about 500 feet of 14 AWG on stand by. Just let me know what is best. And can the umm nut on the back of Z or ZW or KW accept a 14 AWG wire?? Its kinda thick. And I hate to use terminals or anything like that, which attach to the wire. They are a pain to get off and go through holes in the tabletop. Let me know!! Thanks.
There are two separate considerations here, safety and voltage drop:
For safety, use wire heavy enough to carry the current safely. The maximum current that it will have to carry is whatever the circuit breaker is rated for. For the Z and ZW, that is 15 amperes; for the KW it is 10 amperes.
The current that a wire can carry is called its ampacity. The National Electric Code allows 14 AWG to carry 15 amperes, 12 AWG to carry 20 amperes, and 10 AWG to carry 30 amperes. The ampacity theoretically doubles every 4 AWG sizes; so you can see that 16 AWG is good for about 10 amperes. These ampacities are reduced when more than a few wires are bundled or confined together. The Europeans generally allow about 1 AWG size smaller than we do for the same current.
When multiple transformers share a common return wire, add the individual currents together, then select the return wire on the basis of the total current. Four ZWs sharing a return would need a wire big enough for 60 amperes, that is, 6 AWG. Unless you know better, it is considered reasonable to assume that all four such transformers will not be supplying full current at the same time, and to relax the ampacity requirement somewhat.
For voltage drop, use Ohm’s law, E = IR, where E is the voltage drop along the wire, I is the current that the wire is carrying, and R is the wire’s resistance. Wire resistance is about 1 milliohm per foot for 10 AWG, 1.25 milliohms for 11 AWG, and 1.6 milliohms for 12 AWG. Resistance doubles every 3 AWG sizes. The current that you use for this calculation should be whatever you think the train (or other load) will draw, not what the transformer can supply. Usually, wire heavy enough to be safe is also heavy enough to have negligible voltage drop.
Return currents in a common return cancel each other if the transformers are out of
If you are having problems with getting full power to all the transformers that are plugged in to one power strip, I would recommend going with two power strips or even going with a heavy duty extension cord to another outlet that is on another circuit and getting power that way.
Personally I don’t like the store bought power strips. I make my own power strips using 14 AWG wire and using outlet boxes and putting in duplex receptacles with a circuit breaker,usually a 15 amp breaker, installed in the outlet box set-up.
Lee F.