Simple (for some) question about amps and volts

It's just a switch, so pick the voltage and the current for a max. Using less of either is no problem.

There are also remote wireless outlets usually made for lamps etc. One can just plug them in and plug your system in.

Thanks CJack.  I'll look into the wireless outlets.  Mainly just wanted something big and obvious for kids.  I certainly don't want to have to find a remote when smoke starts pouring out.

As for the switch, yeah, if it was too many amps I'd be fine but it's too many Volts and too few Amps.  So my question was if I use lots less Volts, does that mean the switch will handle more Amps?

Why not use just a Household switch.  I use one with an indicator light so I can see its status when leaving the room.  Match the switch to the current rating of the breaker in the service box controlling the circuit.

No on the volts X amps = a constant. For switches, max amps don't change with volts used.

Will,

A switch is rated for the maximum volts - amps.  If you have 120 volts - the maximum amps is still 10 amps.

Larry

Thanks CJack.  I was afraid of that.  Might go with Jims idea then.  Just thought a big red button would be more fun.  It's really something how many emergency stop buttons there are rated for 10 Amps and I can't find one.

I did find these power tool shut-off switches the other night so I might consider them as well.  Just not as neat as those standard emergency shutoff switches but easier to hook up.

http://www.amazon.com/POWERTEC...words=emergency+stop

http://www.amazon.com/Rockler-...y+power+tool+shutoff

http://www.amazon.com/Easy-EZO...y+power+tool+shutoff

I like the Rockler one but its much higher cost than Jim's idea.

Just would prefer the one below but it doesn't look like anyone makes one for normal American household current.

Thanks,

-Will

You could use the one in the bottom picture that you like to operate a contactor or power relay with a 20-30 amp rating to switch off the actual power.

Will,

Buying a switch rated at more amps than that of the breaker on the circuit your using may be a waste of money if you can find a switch with less current capacity.

Jim, All our house circuits are either 20A or 15A.  In the case of the train room it is 15A and given our ZW is 15A and we'll probably have some other power supplies connected I figured we might hit 15A.  I guess I was thinking it would be better to trip the breaker than melt a switch, but I'm new at this.  This is not a dedicated circuit at this time so there are room lights and other outlets on the same circuit so I'm not sure we could pull more than 10 amps.  I may just have to wait and test what we are pulling once we are up and running (hopefully later next week).

RTR, I was starting to think about a relay option.  I guess my current hang up is I'm not sure how that would work unless I had a separate power supply running the relay.  Not sure if I could turn anything on if the button was cutting power to everything.  Humm, I'm tired and will have to think about that.  They have relays that only need 12VDC to switch 15A 120VAC so I might could just run a small laptop type power supply for that one thing and have everything else after the stop switch.

I did find this button below, rated at 16A, and it is magnetic.  If the power went off the button would stay off when the power comes back on.  I could see that being good. It is just not as obvious and easy to hit from anywhere as a big old STOP button.

http://www.ebay.com/itm/371186392283

Thanks everyone for your help.

Simple but effective residential 15 amp snap toggle with pilot light. Replaced rocker type which got accidentally cut off too often. Inexpensive.

20 amp commercial type is available from Industrial Electrical Suppliers.

Higher voltage ratings, in this case (600 volts), indicates that the contact points can safely disengage, (Open), up to that voltage. In some cases, and environments, the contacts will arc over, when opened, which is not what you want to happen on a safety, off, switch.  A switch rated at (600volts) should work quite well at 120 volts, the cost may be another discussion.  

You would just feed the emergency stop switch before feeding the relay. Could be the same circuit.

I re-read your original post and 'from the wall on' you might be better off with something like cjack was talking about. The remote stop devices have been discussed here a few times and some here are using them. I don't recall the brands they were using but here is a link to one. There are MANY others to choose from. These would be very simple and very reasonably priced. They are available with multiple outlet control as well. 

Remote power switch

In my earlier post about the switch and relay, I was thinking more of a power feed to the whole train room, that may not be ideal for just from the outlet on.

Will the one you're looking at might be fine. You're thinking that a zw is 15 amps is incorrect. At 120 volts a ZW is only less than 3 amps and that would only be at full capacity. 10 amps at 120 volts is 1200 watts so the easy way to see if it will work is look on the power plates of everything you want to run and add up the watts. And keep in mind that all the wattage ratings are at full capacity of the unit.

Ron

given our ZW is 15A

No way.  A ZW pulls, in an overload condition (short circuit on layout side) probably 4 amps at the most from the 120-volt line.

I run 3 transformers from a 20-amp receptacle, with a 10 or 15 amp breaker in the outlet strip.  Never has blown.

Wow!  Really good to know.  I guess I had the wrong idea.  I looked at an Ohms Law Calculator and at 18V 250W comes out to 13.8A but then if I change the Volts to 120 the amps drop to 2A.  I guess that is closer to right.  OK, well, I got my switch question answered but learn a lot more so thank you very much.

Just for the record.  I did find this switch box that is 16A on the switch and 18A on the emergency stop button.  However it sounds like a 10A switch might work now and if that Is the case then there are hundreds out there.

https://www.grizzly.com/produc...agnetic-Switch/D4155

I'll probably go with this option and see how it works.  I'll post a review here if I do.

I think most of this has been covered to some extent, but heres my take on it:  

Short answer is you can run Four 275 watt ZW's at full( breaker's gonna trip) load on a 10 amp line, so that should be more than enough for what it sounds like you have.  

When buying a switch, relay or such you cant go past the current rating no matter what voltage you run at, as the contacts may arc/weld even at low voltages with too much current.  

On the other side of this, when rating the power consumption of your transformers, you DO change current with voltage.  Ex: watts = volts x amps, so on your 275 watt ZW, you have say, 15.5 amps at 18 volts, but on the plug end you are only drawing about 2.3 amps at 120 volts.  in the real world we're not usually drawing max output from our transformers, so you're realistically looking at something in the neighborhood of 1amp draw at the source line.  

I'd figure efficiency in there as well.  The old PW transformers are rated on input power, and they're 80-85% efficient at most.  At full power, an old ZW gets pretty warm, all that heat is the losses in the power conversion.