So we got this Ansul r-102 fire suppression system at the job and I’ve never done a shunt before let alone a fire suppression system. My question is, with the 2 micro switches can someone tell me how to hook up the fire alarm( NO, NC, C), and same for the shunt wires? I’ve got a brown, (NC), black, (NO), and red, ( C) for the 2 micro switches . Also, I was planning on sending a 12/2 mc for the shunt control wires. Do I need any power to the Ansul? Thanks!
Shunting a single 20a ckt.
- Thread starter Jha
- Start date
- Status
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
If you’re shunting only one circuit, you can use that circuit to power the shunt trip on the breaker thru one set of the N/O contact on the Ansul head. The other set of contacts will be for your fire alarm, you will need to know if it’s a contact closure that triggers the alarm (normally). And yes, the 12-2 is fine, as it is just a switch leg.
So my common and normally open from one ansul micro switch to the control wires of the shunt breaker? And the same on the fire alarm, they told me to use the NO .
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
And the common to the load side on the shunt breaker? Sorry I’m a 5th year and I’m tackling this for the first time. Lol
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
The first one I ever done was back in the 80’s, just out of tech school. I knew in theory how it should work. The foreman wanted me to hook it up, but didn’t have a clue as how. He was even scared to open the cabinet door afraid he would set it off. I read the instructions, it said “Pull pin, strike button” so I figured if I pulled the pin, and was careful not to strike the button, I would be ok! LOL! You can test it by pushing the micro switch without setting off system.
Sorry last question, could I use a 2 pole shunt breaker that way I don’t have to share the same screw with the common from the ansul as the load from the shunt?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
Ok I lied. I got a theoretical question (last one). Couldn’t I shunt a non shunt breaker by coming off of the breaker to my NO contact, and with my other wire I go back to ground on the panel? So it shorts the breaker once the system changes state? What’s the difference?
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
It works, but probably not a great idea, the higher the available fault current the worse of an idea it may be. At very least how do you know you didn't destroy the light duty contact when you test it or it actually functions? May not work next time it is called on. You want low current to assure this doesn't happen.
An idea I never have done but have given some thought to is to use a GFCI breaker and create a neutral to ground fault with the control circuit.
I like that idea, too, I just don’t know if it would pass the inspector
I’m having a hard time finding shunt trip breakers
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Welcome to the forum.
How you connect the microswitches and the power depends on the system you're connecting them to. Some systems have a control box that controls everything, and some have nothing but manual switches.
If there is a control box, it should have a wiring diagram. Many hoods have built-in switches for fans and lights. Some systems need to be wired from scratch. We need to know details about the system you have.
A shunt-trip breaker is not one you wire to be shorted to trip, it's a breaker with an electro-magnet that mechanically trips the breaker. Think of it as a breaker that can be turned off by "remote control."
Some shunt-trip breakers can not withstand the coil being constantly energized. One simple way to do that is to have the tripping current supplied by the circuit the breaker itself is powering.
The breaker will have two (or more if it also contains contacts) wires, one of which is normally connected to the neutral bus, and the other that receives the 120v pulse to make it trip.
There are rules for how the system should behave when there's a trip. They might vary slightly in some localities, but here's the rules in my area:
Exhaust fan must turn on or stay on.
Make-up fan must turn off or stay off
All appliances must lose power
All receptacles must lose power
Hood lights must turn off
Local horn/strobe or building alarm
How you connect the microswitches and the power depends on the system you're connecting them to. Some systems have a control box that controls everything, and some have nothing but manual switches.
If there is a control box, it should have a wiring diagram. Many hoods have built-in switches for fans and lights. Some systems need to be wired from scratch. We need to know details about the system you have.
A shunt-trip breaker is not one you wire to be shorted to trip, it's a breaker with an electro-magnet that mechanically trips the breaker. Think of it as a breaker that can be turned off by "remote control."
Some shunt-trip breakers can not withstand the coil being constantly energized. One simple way to do that is to have the tripping current supplied by the circuit the breaker itself is powering.
The breaker will have two (or more if it also contains contacts) wires, one of which is normally connected to the neutral bus, and the other that receives the 120v pulse to make it trip.
There are rules for how the system should behave when there's a trip. They might vary slightly in some localities, but here's the rules in my area:
Exhaust fan must turn on or stay on.
Make-up fan must turn off or stay off
All appliances must lose power
All receptacles must lose power
Hood lights must turn off
Local horn/strobe or building alarm
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Another option is to use NC contact on the suppression system and open control circuit to a contactor controlling the load(s) under the hood. This generally means that coil is usually energized pretty much all the time. If you need to turn the fan on when unit trips you don't want the control circuit dropping out if it is on same shunt trip breaker as a load under the hood.
Bottom line is there is more than one way to do this. Shunt trip breaker(s) seems to be pretty popular way though.
What kind of breakers? Square D seems to be months out on anything needing factory ordered lately.
- Status