shunt trip breaker/E-stop circuit

[bearcat1]

Hello everyone! I am new to the site and have a problem that I need help with.

I have a 120/208v panel that has a shunt trip breaker in it. the purpose of the breaker is to kill the panel in the event of emergency. the breaker itself has three control wires....a black, a red, and a white. the e-stop circuit consists of a 120v circuit that feeds one side of a n/o momentary contact pushbutton. the other side of that contact returns to the black wire on the breaker to trip it open. there is also a momentary contact n/o keyed switch at the e-stop location that has the same feed as the pushbutton. the other side of that contact returns to the red wire on the breaker to ( i assume) close it after the emergency situation is resolved.

I have two problems with this.
#1 I can't make the breaker shunt open when I apply 120v to either the black or red on the breaker...( the white is landed on the neutral bar)

#2 the 120v for the e-stop circuit is fed from the very panel that the shunt trip breaker is intended to de-energize so if i do get the breaker to open the control power will be gone and that will prevent closing the breaker.

I am finishing a job that someone else started and trying to piece this together without knowing what demoed or why

thanks for any help that can be offered

 

[luckylerado]

What kind of breaker is it? Is the shunt an accessory or is it built right in?
On most larger breakers that are shunt capable there is a small access panel on the front of the breaker into which you field install accessories like shunt coils or dry supervision contacts. It sounds to me based on your description that you have a set of supervision contacts installed rather then a shunt coil. Shunt coils will only have 2 leads, one for neutral and one for control, whereas a supervision relay will have a common n/o and n/c. I have never seen a shunt trip breaker that could be resettable via control wiring. They are always in my experience manual reset only. Also some shunt capable breakers will have multiple configurations for their accessories so I suppose it is possible that the accessory is installed in the wrong slot or the wrong orientation to the trip lever inside the breaker. I may be able to be more help with a part number from the breaker.

The e-stop. Must you turn the key to push it or turn the key to reset it?

 

[sii]

I doubt (although I'm often wrong lately) that the red wire is used to reset the breaker. Breaker reset is usually accomplished with the handle as you would any other breaker.

It is possible that the three wires are so that you may use either 120 or 208/240 volts to trip the shunt. You would use, for example, white/blk for 120 or red/black for higher voltage trip circuit.

 

[jim dungar]

I have never seen a breaker shunt trip coil that has more than 2 wires. Nor can I think of a shunt trip that has different colored wires.

 

[stew]

all the ones I have seen rest manually with the main.

 

[hillbilly1]

What kind of breaker is it? Is the shunt an accessory or is it built right in?
On most larger breakers that are shunt capable there is a small access panel on the front of the breaker into which you field install accessories like shunt coils or dry supervision contacts. It sounds to me based on your description that you have a set of supervision contacts installed rather then a shunt coil. Shunt coils will only have 2 leads, one for neutral and one for control, whereas a supervision relay will have a common n/o and n/c. I have never seen a shunt trip breaker that could be resettable via control wiring. They are always in my experience manual reset only. Also some shunt capable breakers will have multiple configurations for their accessories so I suppose it is possible that the accessory is installed in the wrong slot or the wrong orientation to the trip lever inside the breaker. I may be able to be more help with a part number from the breaker.

The e-stop. Must you turn the key to push it or turn the key to reset it?

I'm thinking your right on it being a contact instead of a shunt trip, I have never seen a shunt trip with more than two wires either, and usually there both black.

 

[chris kennedy]

It sounds to me based on your description that you have a set of supervision contacts installed rather then a shunt coil. Shunt coils will only have 2 leads

I have never seen a shunt trip with more than two wires either, and usually there both black.

Agreed, but it seems like the following experiment would have tripped the control breaker and smoked the aux contacts.

I have two problems with this.
#1 I can't make the breaker shunt open when I apply 120v to either the black or red on the breaker...( the white is landed on the neutral bar)

 

[hillbilly1]

Agreed, but it seems like the following experiment would have tripped the control breaker and smoked the aux contacts.

But if the white is not the common, applying 120 to either the black or red would not complete a circuit. White may be the N/C or N/O, and one of the other colors is the common, as you know, manufactures do not go by the same color codes as we do, just hooked up a level III car charger the other day where white was used as one of the phases.

 

[chris kennedy]

White may be the N/C or N/O, and one of the other colors is the common,

True if white is N/O.

 

[brian john]

With the CB open/off put a meter between the 3 conductors checking for continuity do the same thisg witht eh CB closed on.

Sounds like others said may be contacts.

What is the ohm reading between the red and white? Black and white?

Many manufactures will have a sticker with shunt trip info on the CB.

What brand of CB, have you checked the manufactures web site?

 

[Jraef]

Hello everyone! I am new to the site and have a problem that I need help with.

I have a 120/208v panel that has a shunt trip breaker in it. the purpose of the breaker is to kill the panel in the event of emergency. the breaker itself has three control wires....a black, a red, and a white. the e-stop circuit consists of a 120v circuit that feeds one side of a n/o momentary contact pushbutton. the other side of that contact returns to the black wire on the breaker to trip it open. there is also a momentary contact n/o keyed switch at the e-stop location that has the same feed as the pushbutton. the other side of that contact returns to the red wire on the breaker to ( i assume) close it after the emergency situation is resolved.

I have two problems with this.
#1 I can't make the breaker shunt open when I apply 120v to either the black or red on the breaker...( the white is landed on the neutral bar)

As the others have said, I seriosly doubt this is a shunt trip, sounds more like Aux contacts to me too.

#2 the 120v for the e-stop circuit is fed from the very panel that the shunt trip breaker is intended to de-energize so if i do get the breaker to open the control power will be gone and that will prevent closing the breaker.

If it WERE a Shunt Trip circuit, all the ST does is TRIP the breaker, it has no effect on opening or closing it normally. Unlike an Under Voltage trip (UVT), it does not need power on it to allow the breaker to engage.

I am finishing a job that someone else started and trying to piece this together without knowing what demoed or why

thanks for any help that can be offered

Maybe that's why this job was never finished, the original guy thought he had a Shunt Trip too and could never make it work, but as it turns out that's because it never was a Shunt Trip!

 

[skeshesh]

I agree with the previous comments about it not being a shut trip. Pics when you get a chance perhaps?

And welcome to the forum.

 

[petersonra]

all the ones I have seen rest manually with the main.

me too.

i agree with the earlier poster that it is some kind of signal contact.

 

[bearcat1]

thanks to all of you for the input. the breaker is very old and i dont know the manufacturer. for clarification the breaker is between the lines that feed the panel and the bus bars in the panel. also, i took the front of the breaker off and can confirm that the wires go to a coil not aux contacts. the theory that the red and black may be for use with either 120v or 208v seems correct. it may also be true that the breaker has to be closed manually because there is a lever on the side of the breaker. there is a contactor for another panel that is closed with the keyed switch so that must be the only purpose for having the keyed switch.

i will take all of your input to work with me tomorrow and try to figure it out. i will also try to post pics of the device.

thanks

 

[stew]

some seimans breakers are 24 vac as well. got me dang curious.

 

[kwired]

check resistances of these leads with breaker in both open and closed positions.

If you have open circuit for every combination of possibilities you either have smoked shunt coils or smoked contacts.

 

[bearcat1]

i think i have it figured out. further investigation has revealed my ignorance. the device is not a shunt trip breaker, it is an ASCO remote controlled switch. the white wire is a neutral (or common), the black wire is for n/c contacts, and the red wire is for n/o contacts. also, the panel has a split bus so the when the switch opens there will still be control power from the top half of the panel. i haven't had time to test this yet but i will update you guys when i do.

 

[hillbilly1]

Be careful not to get confused on the connections of that type of switch, "L" means line(or neutral if 120 or 277 volt coils) , "O" is open, and "C" is close which is power by the opposite leg depending on which state you want the contactor in. The letters are kinda hard to see, but are near the connections.

 

[bearcat1]

Be careful not to get confused on the connections of that type of switch, "L" means line(or neutral if 120 or 277 volt coils) , "O" is open, and "C" is close which is power by the opposite leg depending on which state you want the contactor in. The letters are kinda hard to see, but are near the connections.

yeah, i saw the letters on there.............thanks

 

[weressl]

I have never seen a breaker shunt trip coil that has more than 2 wires. Nor can I think of a shunt trip that has different colored wires.

The multiple wires are used to either incorporate the integral switch that opens when the breaker is tripped, or to bypass-it. If you bypass it, make sure that the trip signal is momentary so that you don't burn up the coil by keeping power on it.

Hope this link works: http://www.google.com/imgres?q=shunt+trip&hl=en&sa=X&rls=com.microsoft:en-us:IE-SearchBox&tbm=isch&prmd=ivns&tbnid=ZK4o0nfeeThDmM:&imgrefurl=http://www.carlingtech.com/products/circuit-protection/learn_more.asp%253Fpage%253Dcircuit_circuit&docid=vaaxnGdAQfMriM&w=360&h=160&ei=Smk4Tq7aE6r20gGNucCzAw&zoom=1&iact=hc&vpx=723&vpy=262&dur=9547&hovh=128&hovw=288&tx=191&ty=78&page=1&tbnh=72&tbnw=161&start=0&ndsp=35&ved=1t:429,r:11,s:0&biw=1280&bih=853