Dedicated 20 amp circuit(s) for a small train room. Need some advise.

[fireman-trainman]

Room size will be approx. 400 sq ft. Would like to run up to (4-6) locomotives on a (2) level (U) shaped track plan. Thinking of using (1 or 2) modern ZW's and (2) postwar LW transformers. Would (1) dedicated 20 Amp circuit and the regular 15 AMP circuit to the room be adequate. Also would like to consider a dedicated 20 AMP circuit to the ceiling fixture to expand the above lighting as the layout build progresses.

[dbaker48]

Fire/Train Man,

Good Plan, I've done essentially the same thing.  16x20 ft room.  Dedicated 20 amp circuit for 1 newer ZW' for the tracks, 1 older ZW for switches, building lights and accessories.  A 15 amp circuit for room outlets (other than Layout), another 15 amp for ceiling lights/fans.  In 7 years never a blown circuit breaker.  Have fun, and enjoy.

[bomber]

Only one thing to keep in mind when designing electrical circuits. NEVER connect more than 80% max. rating of the transformers to your circuit. Example - if your transformer is rated max output of 200 watts - the MOST load you can run without tripping a circuit breaker(transformer) is 160 watts for that transformer. Calculate the wattage of each locomotive you wish to run, add 4 watts per caboose or passenger car, add accessories and come up with your total load. If the total load is more than 80% max. transformer rating, add a second transformer. The same goes for circuit rating. A 20A circuit will handle 16A continuous duty without overheating or tripping. I ran two 20A circuits, one duplex outlet per circuit in my train room. Modern circuit breakers are 1/2 the size of the old breaker. The electrician can install two breakers in the space of one, so even if your distribution panel is full, he can add other circuits. Good luck and do it safely. bruce

[ADCX Rob]

bomber

...Example - if your transformer is rated max output of 200 watts - the MOST load you can run without tripping a circuit breaker(transformer) is 160 watts for that transformer.

Not necessarily true. A 180 Watt PowerMaster will put out 180 watts continuously... a 135 Watt PowerMaster will put out 135 watts continuously... an 80 Watt CW-80 will put out 80 watts continuously... A 180 Watt GW-180 will put out 180 watts continuously...

A ZW is rated at 250/275 watts on the mains, 190-205 watts continuous output, with a breaker for 14 amps.

[phillyreading]

I would say that two 15 amp circuits for the outlets should work fine. At 15 amps you can draw up 1800 watts from the wall outlet. You need to add up all your transformer wattages (what is used by the transformer and not the output rating). For example 180 watt GW may use 210 watts from the wall outlet, the wall outlet watts are what you add up for the total watts. For lighting 15 amps should be more then enough unless you are using very high power spot or flood lights. The new CFl's use very little watts, also a four foot fluorescent lamp uses about (50 watts to start)40 watts continuously. Miniature tree lights, made today, for the holidays use very little watts per string. Also you can use rope lighting for background lighting effects.

[phillyreading]

The post war ZW has an internal circuit breaker rated for 15 amps and can take at least 20 seconds to trip. Don't count on the post war ZW protecting newer electronics at all as the internal breaker is mounted on the common side and does not effect terminals A thru D. You must add some lower rated breakers to the A, B, C & D terminals for best protection, 7 or 8 amps will work good.

[ADCX Rob]

...Don't count on the post war ZW protecting newer electronics at all as the internal breaker is mounted on the common side and does not effect terminals A thru D...

Don't count on the postwar ZW, or any transformer, for protecting newer electronics at all if you are relying on circuit breakers alone. The damage from over voltage spikes is already done long before the fastest breakers can act, and it's cumulative damage. You need Transient Voltage Suppression to clamp spikes, breakers do nothing beyond protecting the transformer and wiring from overcurrent.

[Laurastom]

Some additional thoughts for consideration. Always comply with the NEC and local building codes first. This will result in two circuits serving the room, one for the duplex outlets and one for switchable room lighting. I doubt you will have 20 amps of lighting. Also light fixtures are generally rated for 15A and wiring them direct to a 20A circuit may be unsafe. If you decide to install some 20A outlets one breaker with multiple duplex outlets should be adequate. I have a four gang box with eight total outlets in the wall. Be sure to use duplex outlets rated for 20A. Make sure all the outlets in the room are fed from breakers connected to the same phase in the breaker panel. Otherwise you will have phasing problems with your power supplies/transformers.

[lionelsoni]

I am unaware of any NEC requirement that lights and outlets be on separate branch circuits.  They are intermixed in my house.  In  particular, I put a duplex outlet in the box with every light switch (and on the same circuit) for convenience in plugging in things like vacuum cleaners.  The only restriction I know of for light fixtures applies to fixture taps, which may be as small as 18 AWG for up to 50 feet from a 20-ampere circuit.

If you have a single outlet on a 20-ampere circuit, the NEC requires it to be a 20-ampere outlet (which, in the US may also accept parallel-blade 15-ampere plugs).  If there are more than one, they may be 15-amperes-only types.  I have yet to see a household appliance with a 20-ampere plug.

[Laurastom]

I just finished completely renovating  our home in Orange County. We were required to have the lights on a separate breaker in all bedrooms and any room that could be used as a bedroom. My train room was interpreted as such a room. Correct on the multiple outlets ony requiring 15A duplex outlets. In my case the inspector required 20A because all four were in one gangbox. 

I did a place in the city of San Diego four years ago and ran into the same requirements in the bedrooms and the den. I never went back to the NEC to double check because the inspector is always right when you need the signoff and the movers are on the way! Thanks for the correction. 

Tom

[lionelsoni]

Although it's called the "National Electrical Code", it is completely optional for local jurisdictions, who may adopt it, amend it, or ignore it completely..

Counting 8 outlets as 1 ignores the diversity principle behind allowing multiple 15-ampere outlets on a 20-ampere circuit.  I had the opposite problem when we built our house.  The NEC deliberately has no limit on how many outlets per circuit, in order to reduce the need for extension cords.  But the city allowed only 12 "outlets" per circuit.  I wanted to make all outlets 2-gang duplex, but the city counted those 4 outlets as 2, limiting me to 5 outlet locations per circuit.  The result is that I have a huge panel of circuit breakers.

Another house that we had for a while did have lights and outlets separated; but I think that was to save the builder the cost of arc-fault circuit breakers for the lights, which do not require them.

 

 

 

[MichRR714]

I went through this earlier this year when I ran the wiring for my train room.  I have two 20 amp circuits that are phased for powering the layout.  Additionally, there are two 15 amp circuits for room outlets, a 15 amp circuit for room lighting and a 20 amp circuit for track lighting.  I think Don gave you good advice above, some others have taken you out into the weeds.

[Laurastom]

Sorry if there is any confusion, sometimes it is too tempting to divert into the weeds. For the benefit of the OP I am in complete agreement with Don's recommendation and it is exactly what is in my new train room. That said I really like the additional circuits you have. My decision was to try to keep the total layout load to 2,000Watts. If I fail at that objective then I will need to run a second 20A circuit. The train room is 16'X20'. 

Tom

[phillyreading]

A 20 amp 120 volt circuit should safelt carry around 2100 watts without any problems. As for the NEC, you may add to it BUT never take away from the NEC!! The National Electric Code must be followed or your power company can legally reject your request for power hook-up and make you re-do the electrical work(sometimes you must start completely over, depends on state or county laws) in your house until it meets the NEC.

[phillyreading]

lionelsoni

Although it's called the "National Electrical Code", it is completely optional for local jurisdictions, who may adopt it, amend it, or ignore it completely..

Counting 8 outlets as 1 ignores the diversity principle behind allowing multiple 15-ampere outlets on a 20-ampere circuit.  I had the opposite problem when we built our house.  The NEC deliberately has no limit on how many outlets per circuit, in order to reduce the need for extension cords.  But the city allowed only 12 "outlets" per circuit.  I wanted to make all outlets 2-gang duplex, but the city counted those 4 outlets as 2, limiting me to 5 outlet locations per circuit.  The result is that I have a huge panel of circuit breakers.

Another house that we had for a while did have lights and outlets separated; but I think that was to save the builder the cost of arc-fault circuit breakers for the lights, which do not require them.

 

 

 

Here in West Palm Beach FL you must go by the NEC or not get any service from Florida Power and Light(FPL).

[lionelsoni]

Most US locations do adopt the NEC, but often with their own amendments (that may or may not be an improvement).  The NEC is updated every three years; but local governments may be one or two versions behind.  For example, although the 2014 code is out, the code in effect in the city of Austin (where I live) is the 2011 one.  They have deleted 38 sections or articles and added dozens of pages of amendments.  Outside of cities in Texas, the state has adopted the NEC, but as it existed in 2001.  The NEC is a good starting point; but you need to find out what your local rules are.

[phillyreading]

Something that I have noticed about the electrical tubing or EMT is that certain places now require a separate insulated ground wire be run inside the EMT as the ground. Noticed it with air conditioning work in West Palm Beach FL. The master electrician said it was because people keep running into the EMT in commercial areas with vehicles or pallet jacks and disconnecting the EMT from the connectors.