Sub-panel control via relay?

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Old 01-07-15, 12:34 PM
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Sub-panel control via relay?

I am considering a simple solution to powering off all the lights in a cottage. If the light loads were all in one sub-panel, is it possible to have a relay control the power to the sub-panel? I have knowledge of low voltage and home automation but little knowledge of high voltage. Thank you.
 
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Old 01-07-15, 02:09 PM
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Yes, it is possible but the "relay", more properly a "contactor" because of the heavy current rating, would be quite expensive and it would also be consuming power while the panel is energized. It may also buzz annoyingly. They do make contactors that only use power when changing state but the cost is even higher than the standard contactor.
 
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Old 01-07-15, 02:12 PM
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How much lighting is in the "cottage"? My vision is would be less than one 15A circuit, not a whole panel? There are a lot of smarthome type switches that could do remote shut-offs.
 
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Old 01-07-15, 07:09 PM
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I would just use and electrically held lighting contactor. How many circuits do you need to control?
 
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Old 01-07-15, 11:57 PM
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I have a subpanel controlled by a 3-pole 60A contactor for my Christmas lights. It's a pretty easy setup, wire your switched lead to the coil, and wire the contactor in-line with the subpanel feed in a 12*12*6 junction box. One of us can give you further diagrams or pictures if that's the route you want to take.

How big is this cabin, and why do you want to turn all the lights off at once?
 
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Old 01-14-15, 03:37 PM
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The cabin is approx 3,800 sq ft on two levels. The idea of turning off all the lights is to make it easy to exit without having to check every room (lazy?). The number of loads to control all the lights is approx 35. Not sure how many amps this will require or how many circuits. The high voltage wiring has not begun.

An alternative is a Lutron Radio RA2 setup or even Insteon controls. What is the price range on the quiet higher end contactor? Some brands and models to look at? Thank you.
 
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Old 01-14-15, 08:08 PM
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Once you determine the number of lighting circuits you want to control, you'll know how many poles you need and then you can call a local supply house. Here is an example of an electrically held lighting contactor. Mechanically held contactors are quite a bit more expensive and require a momentary signal to operate them. If you choose to go with mechanically held, I'd use an Asco 917 series or equivalent from Siemens, GE or Cutler-Hammer (all made by Asco).

Used GE Lighting Contactor CR460B with 12 Pole CR460XP32 | eBay
 
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Old 01-19-15, 12:07 PM
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Thanks for the link. Some more information on the cabin and a typo from before as the cabin is only 1800 square feet.
- 140 fixtures
- at 60w average = 8,400 Watts
- 1440w per 15A circuit = 6 x 15A circuits needed

Mechanical or electrical contactor? Are you able to explain in more detail what I will need to do the job? What are the approx pricing on contactor needed for this? Thanks.
 
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Old 01-19-15, 01:26 PM
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It would definitely be an electrical contractor. Instead of using a large contactor however I would definitely go the Insteon or other home automation system instead. Going this route would also give you some other flexibility which he wouldn't have was the contactor and the costs would be about the same or possibly lower for the home automation solution.
 
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Old 01-19-15, 07:32 PM
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Mechanical or electrical contactor? Are you able to explain in more detail what I will need to do the job? What are the approx pricing on contactor needed for this?
If you decide to go the contactor route, I'd suggest an electrically held contactor. You'll have to purchse in addition to the contactor an enclosure for it that can be mounted at the service panel for the building. Each lighting circuit hot wire is run through a set of contacts on the contactor and the coil on the contactor is controlled by a single pole switch wherever you choose for the control station to be. I'd recommend a 120 volt coil or it could also be done with low voltage, but 120 volts might be easier. I suggest the electrically held over the mechanically held contactor mostly because of cost, a mechanically held contactor is quite a lot more expensive although they usually last 20 or more years with no problems.

I can't help you with pricing. Just call your local supply house and tell them how many circuits you want to control and I am sure they can give you a catalog number and price. OR....you can Google lighting contactor and find one that way.
 
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Old 01-19-15, 09:34 PM
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You can use three pole definite purpose contactors or one like in the link below. In the link is an Asco HD switch that is electro/mechanically engaged. This type generates no hum or buzz when in operation.

91862031C :: Lighting Contactors :: Contactors :: Mr Supply
 
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Old 01-19-15, 11:08 PM
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I would not use an electrically held contactor. Even if the contactor coil only uses ten watts that would amount to over 3.5 kilowatt hours over the course of a month if it was energized 50% of the time.

140 fixtures in an 1800 square foot cabin? I live in a 1500+ square foot house and including the lights in the garage/shop I only have about 14 lighting circuits, defined as having one or more lights controlled by a single switch. I think that the Insteon solution, because if its versatility is probably the best. Otherwise, if the circuit panel(s) is/are near the exit door I might consider a sub-panel with all the lighting circuits and then simply trip the circuit breaker for that sub-panel to turn off all the lighting.

In my previous home I had all relay-controlled lighting and had a single switch at the front door that would turn off all the lights and set the furnace to the lower temperature. Has a second switch at the bedroom door that would do the same. Of course I was able to get all the relays for free or at surplus prices so the cost was not a factor. In my current home I decided that merely walking around turning off the switches was both easier and more cost effective.
 
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Old 01-20-15, 09:11 AM
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You can use three pole definite purpose contactors or one like in the link below. In the link is an Asco HD switch that is electro/mechanically engaged. This type generates no hum or buzz when in operation.
The cheapest way to go is using definite purpose contactors. The only objection I have with them is the noise when they SLAM in. Noise is not objectionable in some cases and I also have used them as lighting contactors. Lighting contactors are silent, no noise when operated. The Asco contactor in PJ's link is mechanically held and will require a momentary switch to operate. It's a good option, but expensive. Whether you use a contactor or home automation solution is entirely your decision.
 
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Old 01-20-15, 11:01 AM
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The only objection I have with them is the noise when they SLAM in.
Considering the OP only wants to use is to make sure everything is turned off when leaving the home I'm quite sure that the noise you're referring to wouldn't even be a consideration!
 
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Old 01-21-15, 07:49 AM
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Considering the OP only wants to use is to make sure everything is turned off when leaving the home I'm quite sure that the noise you're referring to wouldn't even be a consideration!
Only the OP can tell us that.
 
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