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[kpautohome]

I'm having 2 transformers installed for outside lighting, one is 900 watt and another is 300 watt. I want to control them both with X10, but I don't want to cause heat problems with the LM14a in the case of the 900 watt transformer in particular.

Basically the lamp module plugs into the transformer plugin, but I'm not sure the lamp module actually has to "handle" the 900 watt load. I would think the transformer itself is what handles the 900 watt load while the lamp is simply controlling the load coming into the transformer.

Dunno, so any help would be great.

[Charles Sullivan]

I'm having 2 transformers installed for outside lighting, one is 900 watt and another is 300 watt. I want to control them both with X10, but I don't want to cause heat problems with the LM14a in the case of the 900 watt transformer in particular.

Basically the lamp module plugs into the transformer plugin, but I'm not sure the lamp module actually has to "handle" the 900 watt load. I would think the transformer itself is what handles the 900 watt load while the lamp is simply controlling the load coming into the transformer.

Dunno, so any help would be great.

Don't use an LM14A with a transformer - you're likely to burn up the transformer or the LM14A or both.

I have 600 Watt landscape lighting transformers plugged into AM486 Appliance Modules and they've been working fine for 10 years.
I suspect there's enough resistance/inductance that you could use an AM486 for your 900 Watt transformer, and if the module does go bad prematurely you're only out about $10 for a new one.

[gil shultz]

Good Evening,

A lamp adapter with a plug and a relay with a 115V (230V) coil would be very inexpensive.  You could use a low voltage relay and a brick that would work as well. Mount the relay in a 4x4  metal electrical box with a single duplex cover.  Use a box connector to bring in the two wires, one for the coil, the other to power the load.  Hook the green wire to the box and the green screw on the duplex.  Connect the white wire to the white screw an the black to the Common of the relay.  The Normally Open contact is then connected to the brass screw on the duplex receptacle.

You could also use a low voltage plug relay with the appropriate relay voltage.  It is important that the relay pull enough current otherwise it will never drop out because of the quiescent current the lamp module pulls. Using an appliance module eliminates the minimum current problem but will have a click every time it is cycled.  The contact requirement would be a minimum of 10A on a 120V system, a bit larger will give you a bit of room assuming the transformers are fully loaded.

Relays can switch humingous amounts of power with very little control energy.  Remember they are inductive and will sometimes cause interesting problems with lamp modules.  They allow you to put the relays close to the load or power source where the larger wire is, the control wires can normally be of a much smaller gage.  I.e. a 22 gage wire controlling hundreds of amps through a relay.  Your AC compressor is a good example of this.

Have Fun
Gil Shultz

[Puck]

Remember they are inductive and will sometimes cause interesting problems with lamp modules.

Gil,

After all that you state this?

Charles stated that immediately and recommended the CORRECT way to automate low voltage lights.

You have some very good and informative posts, however, I feel ones like this and making regular receptacles dimmable have potentially dangerous consequences.

A lot of people with various electrical skill levels (starting from absolute zero) read these posts, not just the person who asked the question. You never know who will just do it without understanding the dangers.

At the very less I suggest that you start these posts with some type of warning stating the level of knowledge one should possess and the potential dangers of the mod right at the top.

All X10 lamp modules/switches clearly state for incandescent lamps only. Nowhere on this forum should it ever be posted / implied that it's ok to ignore this caution. When someone mentions using a module outside of it's intended electrical environment, they should only be directed to the correct module to use as Charles did.

120VAC is not only an electrical hazard that can kill... it can also starts fires.

Cheers

[Noam]

When I installed my low-voltage lighting, I ran into the same issue. I wanted to use a wall switch to control it, but the transformer didn't work through the wall switch.
I decided instead to use an appliance module. I haven't had a moment's trouble with it (unless you count my gardener running over a few of the lights with his mowers every few weeks) in the three years I have had them installed.

[gil shultz]

Good Evening,

You are correct the 2002, 2005 and 2008 National Electrical Code forbids dimming split outlets in section 404.14.  However I could not find it in the 1993 NEC (I do not have all of them).  I contacted the inspector and asked what code they use.  They use the state Residential Code which does not prohibit dimming.  Consequently what I have is legal and to code in this state.

I did a bit of research and there is a lot about that particular section of code, promoted by Lutron.  A bit of further research shows they have a patent on there system consequently there will not be another brand that is interchangeable.  They also got the UL approval and limited to only there dimmer.  Hmmmm I wonder why?

Any idea how 404.14 became part of the code and who promoted it? 

As far as plugging in laptops, little bricks etc they may or may not work.  If they are UL or CSA approved (they should be) there will be no fire or anything like that although they may get hot and blow there thermal protection. 

It is important to also check local regulations as well.  A lot of communities do not subscribe to the NEC, some are much more stringent some are more lenient but that varies by section.

My post was correct per the building codes in the area I live.

Have Fun
Gil Shultz