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    Light switching suggestion

    I'm doing some work at an ambulance corps building in my home town. They would like to have the garage lights come on when they are backing the rigs into the garage. They currently have 3 bays where there are a set of three two-lamp 8' T-8 fluorescent lights on either side of each rig. I've already converted one set (6 lamps) to LED's wired direct. The lighting circuit is currently drawing 10+ amps. There are also two 3-ways and two 4-ways in the switching scenario. I was thinking about using a Caseta Pro switch, leaving one 3-way and both 4-ways in place and providing each rig with a visor clip remote. However, the Caseta switch is only rated for 5 amps. Does anyone have any suggestions for another method of switching in this scenario?

    Thanks in advance.

    #2
    I had to do something similar in a garage. I was using a Lutron RF wireless switch (basically the same as Caseta) and soon realized it was too much for the switch. To remedy this, I put in a contactor. I used the wireless switch to energize the coil of the contactor and the contacts to run the lights. You can use the wireless for the 3 & 4-ways, up to ten I think.
    [COLOR=navy]If you aim at nothing, you will hit it every time![/COLOR]

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      #3
      191203-1007

      goldstar:

      Consider a GE RR relay. This is a bistable relay with 24 V coils for set and reset. Coils can ve operated from either DC or AC. I prefer DC. These are strictly momentary. Continuous applied power to a coil can overheat it.

      Control is from paralleled SPDT momentary spring return to center wired switches. There is really no practical limit on the number of paralleled control switches. You can use any RF controlled pair of SPST switches to also control the RR relays, such as garage door openers. Photocells, ultrasonic sensors, and motion sensors can be used as triggers.

      Google has become an almost useless search engine. I can not find a direct link to a GE site that discusses RR relays.

      These are a good device when properly used and understood. But most electricians don't understand the devices.

      .

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        #4
        How are the doors operated? Or are there too many times the doors would be open and you don't want the lights on?

        How many people are in the ambulance? Everyone needs to stay in it while it's backing in?

        Comment


          #5
          Originally posted by goldstar View Post
          I'm doing some work at an ambulance corps building in my home town. They would like to have the garage lights come on when they are backing the rigs into the garage. They currently have 3 bays where there are a set of three two-lamp 8' T-8 fluorescent lights on either side of each rig. I've already converted one set (6 lamps) to LED's wired direct. The lighting circuit is currently drawing 10+ amps. There are also two 3-ways and two 4-ways in the switching scenario. I was thinking about using a Caseta Pro switch, leaving one 3-way and both 4-ways in place and providing each rig with a visor clip remote. However, the Caseta switch is only rated for 5 amps. Does anyone have any suggestions for another method of switching in this scenario?

          Thanks in advance.
          One solution would be to change out your switches to Nlight Air enabled devices (RPOD is a typical switch used for 3 way applications). Throw in an N-Light Air power pack before any fixture if zoning is needed. Use an Nlight Air Occupancy sensor pointing at each garage door to turn on specific fixtures when triggered.

          Comment


            #6
            Before proceeding I suggest doing a test to determine whether the wireless switch system you select has adequate RF coverage for the application, and that it will work during radio transmissions from the ambulance if that is required. Such a test would be done with a remote inside the ambulance and with it backed up from the door at a distance that they would want it to operate reliably. The Caseta or other wireless switch would need to be mounted and powered inside, but it wouldn't necessarily have to have any relays or other wiring to the lights at this point. But at least a test light or meter would be needed to indicate the switch is operating OK.

            I think many ambulances have a metal wall behind the cab which could block or at least attenuate the RF signal some amount. If I remember correctly the Pico/Caseta has a design range of around 30 ft with an ability to penetrate most building materials, but metal can pose a problem if it presents a lot of blockage. Also, would they expect the RF remote to turn on the lights when the (most likely metal) doors of the garage are closed? If so an RF sensor/ switch mounted on the outside of the building might be needed.

            Comment


              #7
              Thank you all for all your suggestions. I came up with another idea. I'm not sure if it going to be Code compliant or not but here goes :

              Each garage door opener has a light on the opener that comes on when the door opens

              That light stays on for let's say 2 minutes

              Each rig has a visor mounted remote that will open the respective door for the bay they park in

              I plan to remove the bulb and insert one of these : https://www.lowes.com/pd/Project-Sou...dapter/3775053

              I can then make up an S/O cord whip with a 2-prong plug at one end that will plug into that receptacle

              The other end will get attached to the coil of a power relay in it's own metal enclosure

              The N/O contacts of all 3 power relays will get connected in parallel to the travelers at the 3-way location in the garage

              All wiring (except for the whip) will be in EMT

              Anyone see anything wrong with this installation ? I figure this way anyone operating the rigs will not have to have a new device to operate or get accustomed to in the rig and can see when they are backing in.
              Last edited by goldstar; 12-04-19, 08:55 AM. Reason: Sorry - bullets didn't show up on the post

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                #8
                That's exactly why I was asking how the doors are operated.

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                  #9
                  I don't know if it technically makes a differerence, but having your S/O cord connect to an inlet would allow the cord to be completely removable and hence a less "permanent" installation.

                  I had a thought that you could use a photocell near the door opener's light to activate the other lights. But commonly available photocells present two issues for your application:
                  1. They are "light off operate" devices and so they effectively close a contact when the light level is low. But you would need the opposite. This polarity issue could be corrected with relay logic.
                  2. Photocells are usually instant-ON when the light level goes low, but have some delay (at least 3 to 5 seconds, sometimes much more) when the light level goes high. I'm sure that there must be ones without delay for industrial controls but they would take some digging to find.

                  Comment


                    #10
                    If you're talking strictly code compliant, then your proposed install is not compliant.
                    1.) Can't use a lamp shell as a receptacle
                    2.) No EGC for the light/relay circuit
                    I know you can use 2-prong cord caps (plugs) on circuits with no EGC. But if there is an EGC, then you must use it.

                    Having said all that, it will work fine, just not code compliant.
                    [COLOR=navy]If you aim at nothing, you will hit it every time![/COLOR]

                    Comment


                      #11
                      Originally posted by Little Bill View Post
                      If you're talking strictly code compliant, then your proposed install is not compliant.
                      1.) Can't use a lamp shell as a receptacle
                      2.) No EGC for the light/relay circuit
                      I know you can use 2-prong cord caps (plugs) on circuits with no EGC. But if there is an EGC, then you must use it.

                      Having said all that, it will work fine, just not code compliant.
                      Thanks Bill. I didn't know you couldn't use a lamp shell as a receptacle. Why do they still make and sell those screw-in inserts ? With respect to grounding, the door openers are grounded via the plug-in cord in the ceiling. The EMT I plan to install housing the relays and power wiring will be grounded once it is connected to the EMT for the 3-way light switch. I didn't think I would be required to ground both ends.

                      Comment


                        #12
                        Might look into using heavy duty reed switches designed for overhead doors. Use those to control relays and/or contactors. Only downside is lights would always be on anytime the door is more than an inch off the floor, unless you put an override switch in.

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