I need to protect my Emergency system panel which is 480/277v 3phase with surge protection. When you land these wires do you give it is own 3 phase breaker, do you land it under the main lugs (if rated for it) or do you go straight to the busbars on the panel? Looking for some advice keep in mind the Main is coming off the generator so this panels main lugs are protected down stream from the panel but not in the enclosure itself. Let me know what you think thank you.
SPD for Emergency System panel
- Thread starter kjroller
- Start date
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
All the design plans that I have created myself or that others have created and that I reviewed show a 3-phase breaker serving the SPD. It is typically 30 or 60 amps, depending on the installation.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
It usually depends on how many surges you are trying to tolerate not the size of the feeder.
In Minnesota I would go with the lower number, while in Florida I would go with the higher.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
Correct. It is a design decision.
I once saw the disastrous consequences of landing the surge suppressor wires on the main lugs.
Seems like the resistance of the #12 may have prevented enough current flow to clear the fault by tripping the 200 amp main.
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
“you get what you pay for. More is better”
Mike Holt.
More meaning protect sub panels and equipment.
Mike Holt.
More meaning protect sub panels and equipment.