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02-27-2013, 03:17 PM   #1
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## Current sensing relay - multiple loops

I want to turn on a light and have this also energize a seperate circuit. I was thinking of using a current sensing relay to do this but the one I am looking at has a trip point of 1.5 amps which is greater than the current that the light will draw (0.4 amps). If I loop the wire through the current sensor 4 or 5 times will this work to make the 0.4A current appear to be 1.6-2.0A to the sensor?

02-27-2013, 03:54 PM   #2
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Quote:
 Originally Posted by jboyton I want to turn on a light and have this also energize a seperate circuit. I was thinking of using a current sensing relay to do this but the one I am looking at has a trip point of 1.5 amps which is greater than the current that the light will draw (0.4 amps). If I loop the wire through the current sensor 4 or 5 times will this work to make the 0.4A current appear to be 1.6-2.0A to the sensor?
What is the seperate circuit you wish to trigger?

 02-27-2013, 03:55 PM #3 Semi-Pro Electro-Geek   Join Date: Jul 2009 Location: Arizona, USA Posts: 2,976 Rewards Points: 2,852 Yes, it would. But that is not the easiest way to accomplish this. Do you need the second circuit to come on only when the light is actually lit (in other words, not come on if the lamp is burned out)? If you don't need the second circuit to actually indicate proper function of the light, then you should probably just use a regular relay instead of a current sensing relay. __________________ I am a lawyer, but not your lawyer. And who cares anyways? We're here to talk construction. This is DIY advice, not legal advice.
 The Following User Says Thank You to mpoulton For This Useful Post: diystephen (02-27-2013)
02-27-2013, 08:03 PM   #4
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Quote:
 Originally Posted by jboyton I want to turn on a light and have this also energize a seperate circuit. I was thinking of using a current sensing relay to do this but the one I am looking at has a trip point of 1.5 amps which is greater than the current that the light will draw (0.4 amps). If I loop the wire through the current sensor 4 or 5 times will this work to make the 0.4A current appear to be 1.6-2.0A to the sensor?
Yes, this will work, and is done on a regular basis.

 02-27-2013, 10:55 PM #5 Newbie   Join Date: Feb 2013 Posts: 8 Rewards Points: 10 The seperate circuit is just another light. Basically, I want a second light in another location to go on when I throw one of the two switches (it's a 3-way) that controls an existing light. I could rip out the wall to accomplish this but I'd rather not do it that way. It's easy to access the wiring to one of the switches, but not to the other switch or the existing light. I guess most people would simply install a motion sensor. But I want the light to go on when I flip a switch, not when it senses movement. So can I use a regular relay instead?
 02-27-2013, 11:38 PM #6 Member     Join Date: Apr 2011 Location: Almost Arkansas Posts: 2,764 Rewards Points: 2,000 It will work. I"ve done a similar thing when measuring the amperage of a thermostat wire, which is below the lowest setting on the ammeter. __________________ Do you want it your way or the right way?
02-28-2013, 06:58 PM   #7
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Quote:
 Originally Posted by jboyton If I loop the wire through the current sensor 4 or 5 times will this work to make the 0.4A current appear to be 1.6-2.0A to the sensor?
Yes. and the current sensor directions tell you this.

 03-01-2013, 01:29 PM #8 Newbie   Join Date: Feb 2013 Posts: 8 Rewards Points: 10 Okay, thank you. One person above suggested that a regular relay could be used. Is this true? Wouldn't there be enough of a voltage drop across the relay coil to make it unworkable to put it in series with a light?
 03-01-2013, 02:39 PM #9 Member   Join Date: Jan 2012 Location: IL Posts: 891 Rewards Points: 776 You wouldn't put it in series. Light wouldn't work. You would put coil in parallel with bulb. Since you already have current sense relay you might as well stay on course. Be sure relay is UL listed and properly mounted or enclosed.
03-01-2013, 04:44 PM   #10
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Okay, thanks. That's what I thought.

I can't put a relay in parallel with the bulb without ripping out the wall. If I could put it in parallel I wouldn't need any sort of relay, I'd just put the other light in parallel with the existing one.

It's got the little "UL" on the outside. I'm planning to put it inside a junction box.

Last edited by jboyton; 03-01-2013 at 04:50 PM.

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