Shunt trip

[hhsting]

I have two questions:

1. Do they make shunt trip breaker such that where their is no power to shunt trip breaker terminal breaker trips and where there is power to the terminal breaker remains open?


2. Is shunt trip breaker switch recognized by code and replacement of grouping main service disconnects? Meaning one main service disconnect is remote and has shunt trip button that is grouped with rest of the service disconnects?

 

[gadfly56]

I have two questions:

1. Do they make shunt trip breaker such that where their is no power to shunt trip breaker terminal breaker trips and where there is power to the terminal breaker remains open?


2. Is shunt trip breaker switch recognized by code and replacement of grouping main service disconnects? Meaning one main service disconnect is remote and has shunt trip button that is grouped with rest of the service disconnects?

1. Yes, it's called a "contactor".

2. Sorry, can't help with that one.

 

[augie47]

1. It appears an undervoltage trip accessory would fit your description. See https://www.se.com/us/en/faqs/FA97648/
2. Shunt trip is not a recognized as a service disconnect.

 

[gadfly56]

1. It appears an undervoltage trip accessory would fit your description. See https://www.se.com/us/en/faqs/FA97648/
2. Shunt trip is not a recognized as a service disconnect.

For "1.", wouldn't that work only for the breaker itself, and not for loss of power to the shunt coil? Assuming you're not using the hot leg of the breaker to power the shunt coil.

 

[augie47]

For "1.", wouldn't that work only for the breaker itself, and not for loss of power to the shunt coil? Assuming you're not using the hot leg of the breaker to power the shunt coil.

From my read, it would be low (or no) voltage to the shunt terminals but I may well be misreading.
An undervoltage trip device is an optional accessory in a circuit breaker that mechanically trips the breaker when voltage to the terminals drops below a threshhold level. The power for the undervoltage trip does not come from within the breaker, so it must be supplied from an external source

 

[kwired]

For "1.", wouldn't that work only for the breaker itself, and not for loss of power to the shunt coil? Assuming you're not using the hot leg of the breaker to power the shunt coil.

Did you check out the link he provided? Voltage being monitored is not from the breaker itself.

I would assume more common use would be with use of some sort of undervoltage relay and you would send a signal to the accessory as long as voltage was acceptable. For that matter and if that is correct you could trip that breaker for many various possibilities and not just undervoltage by opening the circuit supplying the trip device.

 

[gadfly56]

Did you check out the link he provided? Voltage being monitored is not from the breaker itself.

I would assume more common use would be with use of some sort of undervoltage relay and you would send a signal to the accessory as long as voltage was acceptable. For that matter and if that is correct you could trip that breaker for many various possibilities and not just undervoltage by opening the circuit supplying the trip device.

I misread the link and assumed it was the breaker line terminals.

So, the second part of your post makes me wonder why you wouldn't do this instead of using a shunt coil? It could be set up as a fail safe operation, like a contactor.

 

[petersonra]

I have two questions:

1. Do they make shunt trip breaker such that where their is no power to shunt trip breaker terminal breaker trips and where there is power to the terminal breaker remains open?


2. Is shunt trip breaker switch recognized by code and replacement of grouping main service disconnects? Meaning one main service disconnect is remote and has shunt trip button that is grouped with rest of the service disconnects?

1. Normally after the breaker trips it has to be reset manually, although some breakers can have motorized operators.

There are various means by which a shunt trip breaker can be tripped on loss of power.

2. The breaker itself is the disconnecting means whether it has a shunt trip on it or not. A pushbutton is not a disconnecting means. It is part of a control circuit.