Air Cleaners To Run While Lights Are On

[John Nordyke]

So, to supplement a Jet air cleaner in my shop I'm going to build 1-2 similar units using 110 furnace blower(s) and off the shelf filters. I've seen several DIY plans that I like. These will be wall mounted, and hard-wired. I want them to run any time the lights are on in my shop, but they will be on a separate circuit from my lights-only circuit. What device or gizmo do I need?

[Lisa Starr]

You need relay with a 120 volt trigger coil. An electrical supply house could help you with choosing the exact model.

[Jim Becker]

What Lisa said, but it's called a contactor. These are the best way to control things from other circuits or when you need to control a large, 240v tool from a lower voltage setup. You will want to put in an additional disconnect/switch after the contactor so you can kill the blowers without turning out your lights, too.

[Ron Selzer]

So, to supplement a Jet air cleaner in my shop I'm going to build 1-2 similar units using 110 furnace blower(s) and off the shelf filters. I've seen several DIY plans that I like. These will be wall mounted, and hard-wired. I want them to run any time the lights are on in my shop, but they will be on a separate circuit from my lights-only circuit. What device or gizmo do I need?

Get one or two of these 20amp form c contact, 24vac or dc, 120vac coil mount on a 4sq box or other j box in line with fan power. install a 24vac doorbell transformer powered by lights, run low voltage wire between transformer and relay(s)
https://www.functionaldevices.com/products/building-automation/details/RIB2401B/

[Jim Becker]

Ron, it seems to me that going to low voltage for the control in this specific situation just makes it more complicated since the contactor can be switched with 120v power direct from the light circuit if it has a 120v control side. I would not add a transformer, etc., which is another point of failure. I would use low voltage, however, for a distributed control setup with multiple points around the shop, such as for DC control if one didn't want a central switch.

[Ron Selzer]

Ron, it seems to me that going to low voltage for the control in this specific situation just makes it more complicated since the contactor can be switched with 120v power direct from the light circuit if it has a 120v control side. I would not add a transformer, etc., which is another point of failure. I would use low voltage, however, for a distributed control setup with multiple points around the shop, such as for DC control if one didn't want a central switch.

Jim
the transformer saves having to run the connecting wiring in conduit, as romex or armor cable. Low voltage wiring less than 100ma transformer is allowed to be run in open air.
Could also run wire in conduit, romex, armor cable etc between lights and relay/contactor and not use the transformer. I prefer running low voltage when I can. Multiple ways to do this, each one has pluses and minuses
IF the fan wiring and the light wiring AFTER the switch are in the same j box or other enclosure than the transformer and low voltage cable is not needed.
The RIB relays allow 24vac, dc and 120vac to trigger allowing multiple options with one relay.
Ron

[John Nordyke]

Thanks for the advice. I already use conduit throughout the shop so easy enough to open another knock out in the relevant 4 squares and insert another run, so I'll just get a 120v activated contactor.

[Ron Selzer]

Thanks for the advice. I already use conduit throughout the shop so easy enough to open another knock out in the relevant 4 squares and insert another run, so I'll just get a 120v activated contactor.

the rib relays I linked to come set up for 120vac or 24vac or 24vdc input to the coil and they mount in a knockout on the side of the box. very handy to use
Ron

[John Nordyke]

Thank you, Ron

[Alex Zeller]

Instead of a mechanical relay you can go with a solid state one. When I built my house I really didn't want to spend big bucks on a central vac even though I did plumb the lines in the walls. So I used a Crydom brand (there are other brands) solid state relay. The vacuum uses 120v so I used that signal for the relay. It goes to an outlet that I plug my shop vac into. When the switch on the vacuum hose is turned on the shop vac comes on. I went this route simply because I deal with lots of relays at work. I the last 20 years I can't remember changing out a properly sized SSR but lots of mechanical relays. The contacts get damaged from arcing and the coils burn up. I mounted it inside a metal electrical box so the metal acts like a heat sink.

[Arthur Fleming]

Just a thought....if the new air cleaners are only on one 125 volt circuit, why not swap out the single pole switch for the lights with a two pole switch, and run the hot for the new circuit through this. it will absolutely turn on the new circuit when the lights are turned on.

[Arthur Fleming]

Just a thought....if the new air cleaners are only on one 125 volt circuit, why not swap out the single pole switch for the lights with a two pole switch, and run the hot for the new circuit through this. it will absolutely turn on the new circuit when the lights are turned on.