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fyritup 12-02-2008 01:34 PM

Hello from the hills
 
Hello everyone,my name is Bill and I was an electrician(Commercial,residential,and industrial) for more than 25 years,now I made my living this way until 1999,when my wife had a brain anuerysm,and everthing changed,now I'm a caregiver for her and do some side work every now and again,I'd like to ask a question that I know the answer to, but cant seem to dig it out of the cobwebs known as my mind,I would like to know what a shunt breaker is and what it's for,now I ask this question on another site and the thread was closed because the guy evidently thought me to be an idiot,but when you dont do things that you normally did on a regular basis and then all of a sudden you dont need to know the answer right away,then sometimes it just slips your mind,can anyone help me please

rgsgww 12-02-2008 02:06 PM

Quote:

Originally Posted by fyritup (Post 192790)
Hello everyone,my name is Bill and I was an electrician(Commercial,residential,and industrial) for more than 25 years,now I made my living this way until 1999,when my wife had a brain anuerysm,and everthing changed,now I'm a caregiver for her and do some side work every now and again,I'd like to ask a question that I know the answer to, but cant seem to dig it out of the cobwebs known as my mind,I would like to know what a shunt breaker is and what it's for,now I ask this question on another site and the thread was closed because the guy evidently thought me to be an idiot,but when you dont do things that you normally did on a regular basis and then all of a sudden you dont need to know the answer right away,then sometimes it just slips your mind,can anyone help me please


I think it is a breaker that can be shut off remotely, the magnetic trip mechanism is wired to an external switch, when the switch is closed, current passes through the magnetic trip mechanism, opening the circuit. It does not turn the breaker to a trip position, but the off.

Billy_Bob 12-02-2008 03:05 PM

I have seen these used as part of fire systems to turn off the main power to a building. For example I have seen this connected to a fire sprinkler flow switch on the riser. A fire sprinkler pops, water flows in the riser, this activates the water flow switch, main power is then shut off to the building via wires going to the shunt trip (and the fire alarm is activated).

I've also heard of them used to shut down power for elevators in a high rise should there be a fire in a shaft. Although the shutdown sequence is quite elaborate because you want the cars to first go to the 1st floor and open their doors before shutting down power (to allow passengers to exit).

fyritup 12-02-2008 04:04 PM

Thanks to everyone,I think my first project is to see where and why they need the thing to begin with,then come back and ask the how fors and so on,you've been allot of help thanks

jbfan 12-02-2008 04:58 PM

We have several in our electronics repair facility.

It turns the main breaker to off at the push of a button.
We also have breakers in the kitchen in case of fire, they shut off.

theatretch85 12-02-2008 09:22 PM

Wow, another topic I was honestly about to post about.

My high school had them in the work shop for the overhead pull-down cords. It was wired as an emergency stop switch to kill the circuits. I've actually been thinking about setting one up in my garage for all the outlets, and keep the lights on a separate 15 amp circuit.

My question since I have not actually installed one before, is what are the rules on wiring one up? Like the remote trip wiring, can I just use some 14/2 for the remote kill wired to a momentary push button for a 20 amp breaker? Of course the circuit would be wired with 12 gauge wire (as it is now), but I am referring to the shunt trip portion of the breaker. Also, if the circuit is shut off remotely like this multiple times, does this degrade the circuit breaker in anyway? (I have heard that a breaker tripping due to over current is no longer fully up to spec on successive trips, maybe I am wrong about this) But I suppose if it does indeed go all the way to off (and not "tripped") then I suppose this would be nothing more than just turning the breaker on and off at the actual breaker itself.

Also, does anyone know what the voltage is to activate the remote trip? I'd assume its line voltage that makes that work and the wire can't be anything smaller than like #14.

InPhase277 12-02-2008 09:46 PM

Shunt trip breakers are used for many applications. As has been stated, they are used where remote disconnection is needed. A low-voltage circuit, 12-24 volts, actuates a solenoid that trips the breaker. Buildings often have a locked button at the entrance where the fire department can kill the power. Often, A/C units will be fed from shunt trip breakers, and the shunt connected to an auxiliary relay in a fire alarm panel. When the fire system goes into alarm, the power to the A/C units is automatically disconnected. Elevators sometimes are wired to shunt trips so that if there is a fire in the elevator shaft, the power is turned off. Etc.

Billy_Bob 12-02-2008 09:48 PM

I'm sure they make anything and everything, but those I have seen were for big monster 3 phase breakers, but the shunt trip wiring was a regular 120V 14 ga. circuit powered by a separate 120V breaker and ran to a switch. So it was just run as any 120V circuit would be run.

InPhase277 12-02-2008 09:49 PM

Quote:

Originally Posted by theatretch85 (Post 192999)
Wow, another topic I was honestly about to post about.

Sure you were:thumbsup:

Quote:

Also, does anyone know what the voltage is to activate the remote trip? I'd assume its line voltage that makes that work and the wire can't be anything smaller than like #14.
Every shunt trip I have ever wired was operated on 12-24 V, and wired to it's button or control circuit with 18-2 data comm cable.

There are 120 V units available, but I have never installed one.

theatretch85 12-02-2008 10:29 PM

Quote:

Originally Posted by InPhase277 (Post 193014)
Sure you were:thumbsup:



Every shunt trip I have ever wired was operated on 12-24 V, and wired to it's button or control circuit with 18-2 data comm cable.

There are 120 V units available, but I have never installed one.

Haha, I really was, I was even watching a 20 amp QO shunt breaker on eBay (it was listed as New in the box and was being listed by a eBay store seller). I was also considering looking for a 2 pole 20 amp shunt so that I could run 2 circuits and have them both controlled by the same shunt switch. From what I can tell, these aren't all that cheap.

frenchelectrican 12-03-2008 02:20 AM

Typically most shunt breaker do have 24 volt circuit however just watchout some do have DC or AC version { most used AC AFAIK}

And the cost wise is not cheap ., :eek: Yeah right ..

Most common appaction of shunt trip breaker is useally founded in Fire Alarm system { useally ANSAL system maybe few others } , Elevator shunt tripping but they have specal control to prevent shunt trip until it get down to first floor then trip the breaker.

The other place I know from time to time they used shunt breaker is for gas pump { that used on main breaker useage }{ the rest of them will have both power and neutal common tripped breaker for gas pump useage.

Merci,Marc


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