I'm realizing this situation wouldn't work the way I described it.
If I power an EPO switch from a breaker in panel contained in a panel with a main shunt trip breaker, this breaker would be shut off after the main shunt trip breaker is turned off. If I were to use this breaker as the source to trigger two shunt trip breakers for HVAC units located in another panel, it wouldn't work since the coils wouldn't energize as the breaker would have no power.
I would have to power EPO from another panel that does not contain the main shunt trip breaker. This way this breaker would be on and able to shunt the HVAC breakers as well.
I- WIRE is correct.
Also, its a good idea to keep the EPO control circuit coming out of the panel that's being shunted.
Around here we are required to do so.
If the power came from a different panel, and someone shut that panel down for some reason, you'd loose your shunt control circuit.
If you've got multiple shunt trip breakers coming out of different panel, you might want to consider a control circuit that doesn't leave all your eggs in one basket.
JAP>
That makes sense about someone potentially shutting off EPO control power without realizing it. Is this a code violation to power the EPO this way though?
I'm worried though that the distance for the main shunt trip breaker to be tripped is less than 5' while to trip the other HVAC breakers in an other panel is about 200' away. I know electricity is fast but is there STILL a possibility of the main shunt trip breaker tripping out first....??? Even if it's a small possibility.
That makes sense about someone potentially shutting off EPO control power without realizing it. Is this a code violation to power the EPO this way though?
I'm worried though that the distance for the main shunt trip breaker to be tripped is less than 5' while to trip the other HVAC breakers in an other panel is about 200' away. I know electricity is fast but is there STILL a possibility of the main shunt trip breaker tripping out first....??? Even if it's a small possibility.
I've also seen instances where they took a 1p breaker in the panel that was being shunted and ran it to the coil on a N/O contactor above the 2nd panel then ran the branch curcuits from the 2nd panel thru the contactor to the HVAC units.
When the 1st panel was shunted it caused the contactor to fall out, thus opening the circuits from the 2nd panel to the units.
Not sure if it's a decent design or not. I've just never been a big fan of knowing a contactor has to be pulled in 24/7 for a scenario like this to work.
JAP>
How much less of a fan would you be if a shunt trip failed to operate because there was no power to the coil? Maybe not a big deal for the first panel that powers the EPO since if the panel is off for some reason then your equipment is already de-energized. The problem would be for other shunts paralleled off the EPO for other panels. If panel "A" is down, or a there's a broken wire, "B" and "C" aren't going to cycle off. These things are typically unmonitored. It's why I prefer contactors that have to be powered on. Constant duty contactors are not hard to find.
For every bad shunt trip you could show me I could probably match it with a burnt out coil.
Jap^
For every bad shunt trip you could show me I could probably match it with a burnt out coil.
Jap^
As gadfly points out, normally open contactors will fail safe and if the control circuit is compromised they will open as well.
With a shunt you have no idea if the control circuit is ok.
No you can't even begin to claim the shut is as reliable as NO contators.
Both have contacts and mechanical parts that can hang up so they are equal there.
In ALL other repects the contractor set up is more reliable and fail safe.