Exhaust fan relay question.

[Diesel Dan]

Look at functional devices. The have RIBs- relay in a box and don’t have a 3 relay version but do have a two relay version as well as the standard siingle relay versions.

Thanks for the suggestion. The RIBs were perfect and props to supplyhouse for fast shipping, I've bought a lot from them over the years. System works as desired.

 

[Diesel Dan]

Ignoring 404.2(C), if 14-2 is run from each switch to the fan could you disconnect power to the switches at the box and use the 14-2 from the switch to the attic as a switchleg? In the attic wire the switches in parallel and connect one leg to the hot, the other leg to the fan and get rid of the relays all together?

The switches had to be isolated from each other because the AFCI breakers will trip each other and one of the 3 is on a different leg in the panel.

 

[mm08822]

The switches had to be isolated from each other because the AFCI breakers will trip each other and one of the 3 is on a different leg in the panel.

AFCIs or not, you don't want to interconnect circuits on the same leg either. If you were to, then you defeat the proper cb rating.

 

[willf650]

I ordered a couple of these for a project today. Maybe they would work for you?

I would avoid buying stuff like that from Amazon. I know it’s cheap but you get what you pay for, just be aware what you are getting.

I’ve bought some name brand DC power supplies from them only to find they did have the brand name but were almost visibly identical but fake.

A lot of stuff you are now getting from Amazon is like eBay. Cheap Chinese stuff with fake “UL” and “CE” labels on the devices.

 

[willf650]

Thanks for the suggestion. The RIBs were perfect and props to supplyhouse for fast shipping, I've bought a lot from them over the years. System works as desired.

Keep functional devices in mind for the future.

They make a lot of innovative devices in regards to relays and power supplies.

 

[Diesel Dan]

If for a standard HVAC system, there is probably an auxiliary relay/output available on your main board or thermostat to control an auxiliary fan.

If a custom system, I would use contactors. Here is an arrangement I have with 4 separate switches, each with a contactor switching on two separate circuits at the same time:

Was thinking of doing similar with a terminal bus bar since I couldn't locally source a insulated bus bar for the parallel outputs. Figured I would get raked across the coals for hack work. So I used 221-415 Wagos. Yours is a simple daisy chain, might upgrade to that. Think I have a couple 8 pole terminal strips kicking around.