Exhaust fan switching
- Thread starter bbuckway
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Jim W in Tampa
Senior Member
- Location
- Tampa Florida
since this is not residential i would use sensers and a relay. Timers would depend on people being smart enough to use them.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
You could still use two 3-ways and a 4-way, along with indicator lights at each switch that don't require additional wiring:
At each switch, wire a pair of 100K 1/4w resistors in series, wire the pair across the travelers, and wire an NE-2 neon bulb between the resistor junction and the neutral.
When the load is on, so are the bulbs. If the bulbs won't go off, the load is open. This is great for remotely-located lights.
At each switch, wire a pair of 100K 1/4w resistors in series, wire the pair across the travelers, and wire an NE-2 neon bulb between the resistor junction and the neutral.
When the load is on, so are the bulbs. If the bulbs won't go off, the load is open. This is great for remotely-located lights.
Cow
Senior Member
- Location
- Eastern Oregon
- Occupation
- Electrician
I have this exact same scenario for 4 bathrooms and one ex. fan for a warehouse. Four single pole switches on switch loops driving a contactor is what I'm going with. Occ. sensors would be ideal, but not if they weren't bid....
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I usually install timer switches but have not used the relay. I used to feed the power in the attic and drop down with switch legs but it is still sending current in 2 directions (paralleling) for a distance when both switches are on. I think the relay or 3 ways is the only way to legitimately do this.
What about using the sp. wind up mechanical timers I used them on tan beds a lot.
To me as far as the paralled switch loops, I dont think this is what the code panel
had in mind when they made this code.They where trying to limit the use of smaller
conductors for feeds if it wheren't for this code instead of running 6/3 to the range
a lot of contractors would probably parallel 3 # 10/3 nm cables what a mess this could be.
But I do like Larry's idea about the neon lamps.
Ronald
To me as far as the paralled switch loops, I dont think this is what the code panel
had in mind when they made this code.They where trying to limit the use of smaller
conductors for feeds if it wheren't for this code instead of running 6/3 to the range
a lot of contractors would probably parallel 3 # 10/3 nm cables what a mess this could be.
But I do like Larry's idea about the neon lamps.
Ronald
Last edited:
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I agree and I really don't have a big issue with it but it can be rejected by an AHJ.
- Location
- Massachusetts
If that is true can you explain the need for an exception allowing us to do it?
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
fishin' electrician
Senior Member
- Location
- Connecticut
Anyone know when and or why they removed "to form a single conductor" from the end of (electrically joined at both ends)? It's in the '99.
Not allowing parallel switching is ridiculous, we're not trying to make a larger conductor here, just operate a fixed load from multiple locations.
I think the OP was wondering if there was anything wrong with energizing the secondary side of the remaining switches when any one of the switches was turned on since they all went to a common load and the answer is no.
As long as the switchlegs are terminated at a common point this is going to be the case whether it is at the motor,or coil on a contactor.
Even on an Occ Sensor with a common power pack.
As far as the parallel conductors issue,this is not a parallel conductor.
You only have 1 conductor leaving the breaker,not 2.
It is a single circuit that has a common load controlled by switching from several locations.
Use a 1p switch but yes it will probably stay running all the time.
Use a spring wound timer if you want at 3 locations, although not standard in a commercial application probably the simplest and will shut off once it times out.
Use Occ Sensors with a common power pack, most common
You could get as fancy or as simple as you need to.
Point is the back feed on the secondary side of the switches is pretty common.
You just need to shut the circuit off before maintaining it so the people turning on the switch in room 2 and 3 dont light you up while your working on switch #1
As long as the switchlegs are terminated at a common point this is going to be the case whether it is at the motor,or coil on a contactor.
Even on an Occ Sensor with a common power pack.
As far as the parallel conductors issue,this is not a parallel conductor.
You only have 1 conductor leaving the breaker,not 2.
It is a single circuit that has a common load controlled by switching from several locations.
Use a 1p switch but yes it will probably stay running all the time.
Use a spring wound timer if you want at 3 locations, although not standard in a commercial application probably the simplest and will shut off once it times out.
Use Occ Sensors with a common power pack, most common
You could get as fancy or as simple as you need to.
Point is the back feed on the secondary side of the switches is pretty common.
You just need to shut the circuit off before maintaining it so the people turning on the switch in room 2 and 3 dont light you up while your working on switch #1
I agree Larry but this not done to increase the capacity but for control reasons.
I sure would not increase the cost, complexity and durablity of the circuits by adding
a relay because of sematics.
Sometime we do need to use common sense.
If you want to use relays why not use touch plate?
Cick here for Example
I don't know if you are familiar with them or not they fit in a 1/2" KO to mount in a metal box ,low voltage side will be out side of box. You may use twisted 18/2 to your low voltage push button switches. You will also need a 40va
120/24 VAC transformer for low voltage AC supply. I also recommend a in line low voltage fuse.
Cick here for Example
I don't know if you are familiar with them or not they fit in a 1/2" KO to mount in a metal box ,low voltage side will be out side of box. You may use twisted 18/2 to your low voltage push button switches. You will also need a 40va
120/24 VAC transformer for low voltage AC supply. I also recommend a in line low voltage fuse.
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