- Location
- Illinois
- Occupation
- retired electrician
For systems with OCPDs in that size range, the only real way to comply with the selective coordination requirements is to use fuses and not breakers.....again, Bussmann wrote these rules.
The fact that the 20's and 40's won't coordinate makes having the 40A breaker on the load side of the ATS even worse.
If there is any short circuit on any 20A LS branch, there is a very good chance the 40A on the load side of the ATS will also trip, which will completely disconnect the LS panel.
The generator will never get a chance to do its job or to provide power to the LS branch. There will be an open circuit breaker right in the way.
Panels on the load side of ATS's should not have main breakers if it can be avoided. If it can't be avoided, they should be coordinated so they never trip before the upstream breakers.
For systems with OCPDs in that size range, the only real way to comply with the selective coordination requirements is to use fuses and not breakers.....again, Bussmann wrote these rules.
They made a very strong case that selective coordination for Article 700 and 701 systems is serious safety issue. In the event of a fault on those systems, the system must limit the outage as much as possible and selective coordination accomplishes that.Question is, does Bussmann have ground to stand on?
So it’s a pure sub panel, MLO?