# Triggering 110V with 347V



## brian john (Mar 11, 2007)

2-pole switch
single pole switch to a two pole relay
Current relat triggered on lighting current.
as noted a transformer on the lighting circuit.


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## electric mike (Jun 15, 2009)

perhaps run the 120v thru a contactor controlled by the 347v lighting circuit? When the light switch closes it could also close the contact coil for the fan.


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## RIVETER (Sep 26, 2009)

Photo eye sounds simplest, to me.


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## mattsilkwood (Sep 21, 2008)

I would either go with Brian's Idea of the 2 pole switch, that is probably the simplest, or electric mike's idea of the contactor, But I would take the 347v through the contactor and use the 120v to drive the coil, a 120v coil will be cheaper and easier to find.


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## MDShunk (Jan 7, 2007)

IF the 347 fixtures are existing, AND the fans are the new work, AND without knowing what's readily available in 347 volt, I'm liking the photocell idea very much. Install it proximal to the fixture closest to the first fan.


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## Jlarson (Jun 28, 2009)

Mike in Canada said:


> I wanted to start a 120V ceiling fan whenever the 347V lighting was turned on. I considered various ways to do it, but none were easy to source. I could use a transformer to get 110V from the 347V and wire it in with the lights - no switching required. I could try to find a RIB relay with a 347V coil, or I could put a photo-eye on the ceiling fan. What would be considered the 'standard solution' for this problem?
> 
> Mike


So the idea is to turn on a fan when the lights come on right, and when you say photo-eye I assume you mean a control that turns on when it is dark out.


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## mattsilkwood (Sep 21, 2008)

Jlarson said:


> So the idea is to turn on a fan when the lights come on right, and when you say photo-eye I assume you mean a control that turns on when it is dark out.


 You could do it like that. Use the photocell to drive a relay. Take the fan circuit through normally closed contacts on your relay. So when the lights are off the photocell will pull in the relay and break the fan circuit. When you turn the lights on the photocell opens, the relay falls out and your fan circuit makes.


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## Navyguy (Mar 15, 2010)

I would be using a small 347 volt relay to close the 120 volt circuit.

The two pole switch would be a code violation in Ontario, although I can't quote the specific section from memory.

Do you have a control box for the lighting or is it just regular 347 volt switches?

Cheers


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## Jlarson (Jun 28, 2009)

mattsilkwood said:


> You could do it like that. Use the photocell to drive a relay. Take the fan circuit through normally closed contacts on your relay. So when the lights are off the photocell will pull in the relay and break the fan circuit. When you turn the lights on the photocell opens, the relay falls out and your fan circuit makes.


Yeah, I have done that a lot. I wonder if such a thing as an inverse photocell is made?

I was just pointing out a potential design flaw(read:smart comment):jester:


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## garfield (Jul 30, 2009)

*photocell uses*

I was humored about the photocell because I was thinking of easy ways to reduce my own demand charge and i was thinking of a photocell to a relay to turn off the hot water heater circuit when the shop lights were on. Seemed a little rough around the edges though.


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## Jlarson (Jun 28, 2009)

If it were me I would use a current switch pulling in a small 120v IEC contactor or if I could find one an IEC contactor with a 347v coil saving on the current switch.


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## Mike in Canada (Jun 27, 2010)

mattsilkwood said:


> I would either go with Brian's Idea of the 2 pole switch, that is probably the simplest, or electric mike's idea of the contactor, But I would take the 347v through the contactor and use the 120v to drive the coil, a 120v coil will be cheaper and easier to find.


 That is a very 'out of the box' answer, and I like it! However, the lights are pre-existing and the fan is new. This solution would complicate things a fair bit in this particular case. Great idea, though... I was in a rut thinking that the 347 has to trigger the 110, but really it could be the other way around in the case of a new system.

Mike


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## Mike in Canada (Jun 27, 2010)

Navyguy said:


> I would be using a small 347 volt relay to close the 120 volt circuit.
> 
> The two pole switch would be a code violation in Ontario, although I can't quote the specific section from memory.
> 
> ...


 The problem with the two-pole switch is that it would be two voltages (and sources) in one box, and yes it's just a regular 347V switch. This is just part of a room in a factory office that has been walled off and is becoming a washroom so it needs a vent fan.

Mike


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## Mike in Canada (Jun 27, 2010)

Update: Part of the problem with this.. problem is that my lead time has been very short. I found out on Thursday that the job has to be done by Monday, and that doesn't leave much time to get 'interesting' parts, like 347V coils for relays. My two options right now are a potted 347V-110V transformer which my electrical supply place happens to have on the shelf (it was ordered by mistake years ago) which is relatively spendy at $120-ish, or I can put a device box in the wall with a timer on it (which is 'situation normal' for washroom fans in this facility). The decision now is whether the time is worth the money. I suspect it is... if I like the looks of the potted transformer then I'll go that route, but if I don't then I'll put in a switch.
I was mostly curious what the 'normal' solution would be, as I've never run into this before. I had even seriously considered swapping their troffers for 120V units and just converting their lighting (only two troffers, and I had them in the truck as leftovers from another job) so I could do it 'easily'.

Mike


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## Southeast Power (Jan 18, 2009)

If converting the fixtures with some ballasts you have laying around is a possibility then you are not going to be in a position to solve the problem by inserting another point of failure such as a transformer, relay or photocell.

I would otherwise install (Brian method) a two pole relay to control the lighting and use the 120 volt fan circuit to control it with a single pole switch.


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## Toronto Sparky (Apr 12, 2009)

Solar Powered fan :laughing:


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## Mike in Canada (Jun 27, 2010)

I appreciate all of the answers... in the end I put a new wall-box in with a timer to avoid the problem of linking the two systems. I enjoyed the different ideas of how to do it in the future.

Mike


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## drsparky (Nov 13, 2008)

Mike in Canada said:


> I appreciate all of the answers... in the end I put a new wall-box in with a timer to avoid the problem of linking the two systems. I enjoyed the different ideas of how to do it in the future.
> 
> Mike


Too bad, I was going to suggest hiring a wino to turn on the fan switch every time the main light comes on and wakes him up, they work cheap.:jester:


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## HAND (Jul 15, 2010)

Speedy, you're starting to PMO with your thread closing powers, why dont you close this one, it is the biggest piece of **** I've read so far here.

On the other hand, I am hesitant to go to the diy forum and tell people to mess around with 120v even though they get helped because they are going to do their crap anyway.

proEC, ...whatever.


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## brian john (Mar 11, 2007)

How can something this simple drag on this long?


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## RIVETER (Sep 26, 2009)

brian john said:


> How can something this simple drag on this long?


People keep posting.:whistling2:


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